Quick-Response Technologies for the Colouration of Wool

A thesis submitted to The University of New South Wales for the degree of Doctor of Philosophy

by

Timothy Alan Petterson

Department of Textile Technology School of Fibre Science and Technology The University of New South Wales

December, 1996 Declaration

I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of a university or other institute of higher learning, except where due acknowledgment is made in the text.

I also declare that the intellectual content of this thesis is the product of my own work, even though I may have received assistance from others on style, presentation, and language expression.

Timothy Alan Petterson

-ii- Acknowledgments

Foremost, I would like to express my sincere gratitude to my supervisor, Professor Michael Thomas Pailthorpe, for his advice, direction, and constant encouragement throughout the course of this thesis.

I would also like to thank the International Wool Secretariat, without whose generous sponsorship, this thesis would not have been possible.

Many thanks to all the staff and students of the School of Fibre Science and Technology at the University of New South Wales for their friendship over the past seven years.

I am indebted to my parents for their continual love and support through all my endeavours. I would especially like to acknowledge my father, who has followed my work with great interest, and been a real encouragement to me.

Finally, I would like to thank my wife Susan, who has endured with me for the past three years of this project. Thank you for your friendship, love and support.

-iii- Abstract

In the 1990's, the demand by consumers for quick-response has increased significantly. In order to satisfy these demands, it has been necessary to modify the processes used. The application of colour to wool is one such process that poses a limitation to quick-response, and as such, needs to be modified.

The objective of this project was to develop new and improved methods for applying colour to wool, very quickly. In order to achieve this objective, two very different approaches were used.

The first approach involved a modification of the wool by use of reactive hydrophobes. Two series of hydrophobes were tested. One was based on the 2,4-difluoro-5-chloropyrimidyl-amino reactive group, and the other on the 2-bromopropenamido reactive group. These reactive hydrophobes were fixed to the wool by covalent bonds and hence produced permanent hydrophobic sites in the wool. As the hydrophobic character of wool increased, so too did its affinity for disperse dyes. With this increased affinity comes the ability to utilise heat-transfer printing as a means of applying colour to wool.

Without exception, all the hydrophobes that were tested demonstrated an ability to increase the affinity of the disperse dyes to wool. In particular, the wool samples that were modified with reactive hydrophobe AB (2- bromopropenanilide) resulted in the greatest increase in hydrophobic character, and hence the most successful dye affinity.

-iv- The second approach also involved a modification of the wool, however, this time it was achieved using an oxygen plasma. Wool samples were exposed to an oxygen plasma in an attempt to alter the fibre surface, making them more receptive to dye uptake. Prior to modification, intercellular diffusion was the only means by which dye moved from the dyebath to the fibre interior. Plasma modification created a second diffusion pathway which meant that dye molecules could also diffuse transcellularly, or through the cells of the cuticle. This additional pathway effectively increased the rate of dye uptake.

Representative dyes from each of the appropriate dye classes for wool were considered in this work. For each of the dyes used, the rate of dye uptake, depth of colour, and fastness properties were examined for both treated and untreated wool samples. The reactive dye Procion Navy HE-R, with the monochlorotriazynl reactive group, showed the most significant variation from the untreated sample. For a sample that had been treated with an oxygen plasma for a period of ten minutes, the rate of dye uptake increased by 100%, effectively reducing the dyeing time by half.

Procion Navy HE-R was also used to examine the effects of varying the length of oxygen plasma treatment, and the size of the exposed sample. Once again, the rate of dye uptake and depth of colour was affected, however, fastness properties were largely unchanged.

Both of these approaches enabled the application of colour to wool to occur more quickly and at a late stage. Thus, the objective was achieved.

-v- Table of Contents

Declaration...... ii Acknowledgments...... iii Abstract...... iv Table of Contents...... vi List of Figures...... xii List of Tables...... xvi List ofAbbreviations ...... xviii

Chapter One INTRODUCTION...... 1

1.1. Preface...... 1 1.2. The Morphological Structure of Wool...... 2 1.2.1. The Cuticle...... 2 1.2.2. The Cortex...... 3 1.2.3. The Cell Membrane Complex...... 4 1.3. The Chemistry of Wool...... 4 1.3 .1. The Chemical Composition of Wool...... 5 1.3 .2. Hydrophobic Side Chains...... 7 1.3 .3. Hydrophilic Side Chains...... 7 1.3.3.1. The Amino Acids with Acidic R Groups.. 7 1.3.3.2. The Amino Acids with Neutral R Groups. 7 1.3.3.3. The Amino Acids with Basic R Groups.... 8

-vi- 1.4. Reactions of Wool...... 9 1.4.1. Oxidation...... 9 1.4.2. Reduction...... 10 1.4.2.1. Reduction with Thiols...... 11 1.4.2.2. Reduction with Phosphines...... 12 1.4.2.3. Reduction with Sulphites...... 13 1.4.3. Hydrolysis...... 14 1.4.3.1. Reaction with Acid...... 14 1.4.3 .2. Reaction with Alkali...... 15 1.4.4. Esterification...... 16 1.4.5. Acylation...... 17 1.4.6. Alkylation and Arylation...... 19

Chapter Two QUICK-RESPONSE METHODS...... 20

2.1. Conventional Methods of Applying Colour to Wool...... 20 2.1.1. Dyeing Technologies...... 20 2.1.1.1. Loose Stock Dyeing...... 20 2.1.1.2. Top-Dyeing...... 21 2.1.1.3. Yam-Package Dyeing...... 22 2.1.1.4. Yam-Hank Dyeing...... 23 2.1.1.5. Piece Dyeing...... 24 2.1.1.6. Garment Dyeing...... 24 2.1.2. Printing Technologies...... 25 2.1.2.1. Direct Printing...... 25 2.1.2.2. Discharge Printing...... 26 2.1.2.3. Resist Printing...... 27 2.1.2.4. Vigoureux Printing...... 28

-vii- 2.2. Transfer Printing...... 30 2.2.1. Melt-Transfer Printing...... 30 2.2.2. Film-Release Transfer Printing...... 31 2.2.3. Wet-Transfer Printing...... 31 2.2.4. Heat-Transfer Printing...... 32 2.3. Factors Influencing the Heat-Transfer Printing Process. 32 2.3.1. Textile Substrate...... 32 2. 3. 2. Dyestuffs...... 34 2.3 .3. Process Variables...... 36 2.4. Advantages and Disadvantages of the Heat-Transfer Printing Process...... 37 2.4.1. Advantages...... 37 2.4.2. Disadvantages...... 40 2.5. Basic Operation of Heat-Transfer Printing...... 41 2.6. Application of Heat-Transfer Printing to Wool...... 42 2.7. Increasing Wool's Affinity for Disperse Dyes...... 44 2.8. Reactive Hydrophobes...... 45 2.8.1. Reactive System...... 47 2.8.2. Hydrophobic System...... 48 2.9. The Inorganity-Organity Ratio...... 48 2.10. Plasma Treatment...... 50 2 .10 .1. Corona Discharge...... 50 2.10.2. Glow Discharge...... 51 2.11. Effects of Plasma Treatments on Surfaces...... 52 2.12. Effects of Plasma Treatments on the Properties of Wool 54 2.13. Commercial Benefits of Plasma Treatment in Textiles... 56 2.14. Dyes for Wool...... 58 2.14.1. Acid Dyes...... 58 2.14.2. Chrome Dyes...... 61

-viii- 2.14.3. Metal-ComplexDyes...... 64

2.14.4. Reactive Dyes...... 66

2.14.4.1. Nucleophilic Substitution Reactions...... 66 2.14.4.2. Michael Addition Reactions...... 67 2.14.4.3. Conventional Reactive Dyes for Wool.... 68

Chapter Three EXPERIMENTAL...... 71

3.1. Materials for Heat-Transfer Printing...... 71 3.1.1. Chemicals...... 71 3 .1.2. Disperse Dyes...... 72 3.1.3. Substrates...... 72 3.2. Facilities...... 72 3.3. Synthesis and Authentication of Reactive Hydrophobes.. 73 3.4. Chemical Modification of the Wool Fabric...... 7 4 3.4.1. Method Used to Apply 2,4-Difluoropyrimidyl Amino Hydrophobes...... 75 3.4.2. Method Used to Apply 2-Bromopropen Amido Hydrophobes...... 76 3.5. Assessment of Modified Samples...... 76 3.5.1. The Determination of the Extent of Modification.... 76 3. 5 .1.1. Percentage Weight Gain...... 77 3.5.1.2. Moles of Reactive Hydrophobe Grafted on the Fabric...... 77 3 .5 .1.3. Fabric Handle...... 80 3.6. Transfer Printing...... 80 3.6.1. Stage One: Production of Transfer Paper...... 81 3.6.2. Stage Two: Transfer of Disperse Dye to Wool...... 81

-ix- 3. 7. Assessment of Transfer Printed Samples...... 82 3. 7 .1. Colour Transfer...... 82 3.7.2. Fastness Properties...... 82 3.7.2.1. Colour Fastness to Dry Cleaning...... 83 3.7.2.2. Colour Fastness to Light...... 84 3.8. Materials for Plasma Treatment of Wool...... 85 3.8.1. Substrate ...... 85 3.8.2. Dyes...... 85 3.9. Facilities...... 86 3.10. Modification of the Wool Fabric with Plasma...... 86 3 .10.1. Sample Preparation...... 86 3.10.2. Plasma Apparatus Used...... 87 3.10.3. Plasma Treatment Conditions and Variables...... 87 3.10.4. Treatment Procedure...... 87 3.11. Tests to Observe the Effects of Plasma Treatment...... 88 3.11.1. Test to Determine the Effect of Different Dyes..... 88 3.11.2. Test to Determine the Effect of Different Exposure Times...... 90 3 .11.3. Test to Determine the Effect of Different Treated:Untreated Exposure Areas...... 90 3.12. Assessment of Colour Parameters...... 91 3.12.1. Rate of Dye Uptake ...... 92 3.12.2. Colour Difference...... 92 3 .12.3. Fastness Properties...... 93

Chapter Four RESULTS & DISCUSSION...... 94

4.1. Assessment of the Modified Fabric...... 94

-x- 4.1.1. Weight Gain of Wool Samples...... 94 4.1.2. Moles of Reactive Hydrophobe Grafted onto the Fabric...... 96 4.1.3. The Extent of Modification and Character of Modifiers...... 97 4.1.4. Fabric Handle...... 100 4.1.5. Yellowness Index...... 100 4.2. Assessment of the Transfer Printed Fabric...... 101 4.2.1. Colour Transfer...... 101 4.2.2. Dry-Cleaning Fastness...... 103 4.2.3. Light Fastness...... 104 4.3. Role of Fibre Structure in Wool Dyeing...... 105 4.3 .1. Mechanism of Wool Dyeing...... 105 4.3.2. The Role of the Cuticle in Wool Dyeing...... 106 4.4. Dyeing of Plasma Treated Wool...... 107 4.4.1. Effect of Different Dyes...... 107 4.4.1.1. Discussion...... 109 4.4.2. Effect of Different Exposure Times...... 115 4.4.3. Effect of Different Exposure Areas...... 117

Chapter Five CONCLUSIONS...... 120

5.1. Conclusions...... 120

Bibliography...... 125 Appendices...... 145

-xi- List of Figures

Figure 1.1. Schematic Diagram of the Morphological Components of a Fine Wool Fibre Figure 1.2. Simplified Schematic Diagram of the Cuticle and Cortex of Wool Figure 1.3. Schematic Diagram of Wool Cuticle Figure 1.4. General Formula of a-Amino Acids Figure 1.5. Condensation of Two Amino Acids to Form a Dipeptide Figure 1.6. A Typical Segment of a Protein Chain Figure 1. 7. Oxidation of Cystine Figure 1.8. Reduction of Wool Figure 1.9. Reduction of Wool with Thiols Figure 1.10. Reduction of Wool with Phosphines Figure 1.11. Sulphitolysis of Wool Figure 1.12. Wool Behaves as an Ampholyte Figure 1.13. Acting as an Acceptor in Nucleophilic Substitution Figure 1.14. Acting as a Donor in Nucleophilic Substitution Figure 1.15. Acylation of Wool Figure 1.16. Some of the Reactions Which May Occur During the Acylation of Proteins Figure 1.17. Alkylation of Wool Figure 2.1. Melt Transfer Printing at Different Pressures Figure 2.2. Film-release Transfer Printing Figure 2.3. Disperse Dye with Bulky Substituent Groups Figure 2.4. Disperse Dye Structures showing Inter and Intra Hydrogen Bonding Figure 2.5. Effect of Temperature on Transfer Figure 2.6. Effect of Time on Transfer

-xii- Figure 2. 7. Effect of Pressure on Transfer Figure 2.8. Effect of Time and Temperature on the Base Colour of Various Fibres Figure 2.9. Dye Transfer Mechanism in Heat-Transfer Printing Figure 2.10. Reactions in a Corona Discharge Figure 2.11. Classification of Wool Dyes Figure 2.12. Ion Exchange During the Dyeing of Wool with Acid Dyes Figure 2.13. Representation of the Rate of Adsorption of Ions by Wool from an Acid Dyebath Figure 2.14. Reactions During Afterchrome Dyeing of Wool Figure 2.15. Chemical Structure of C.I. Acid Violet 78 Figure 2.16. Chemical Structure of C.I. Acid Orange 148 Figure 2.17. The Reactive Centers on 2,4-Difluoro-5-Chloropyrimidyl Amino Dyes Figure 2.18. The Reactive Centers on a-Bromoacrylamido Dyes and Vinylsulphonyl Dyes Figure 2.19. Reaction of Lanasol Dyes with Wool Figure 2.20. Reaction with Drimalan F and Verofix Dyes Figure 2.21. Reaction with Hostalan Dyes Figure 3.1. Synthesis Route for Reactive Hydrophobes Containing the 2,4-Difluoro-5-Chloropyrimidyl Amino Group Figure 3.2. Synthesis Route for Reactive Hydrophobes Containing the 2-Bromopropenamido Group Figure 3.3. Reaction Schemes for the Modification of Wool with the Reactive Hydrophobes Used in this Project Figure 3.4. Arrangement of Samples in Preparation for Dry-Cleaning Figure 3.5. Diagrammatic Representation of Aluminium Template 1 and its Placement on the Wool Sample During Plasma Treatment Figure 3.6. Diagrammatic Representation of Aluminium Templates 2 and 3 and their Position on the Wool Sample

-xiii- Figure 4.1. The Extent of Modification Versus Applied 2,4-Difluoro-5- Chloropyrimidyl Amino Hydrophobes Figure 4.2. The Extent of Modification Versus Applied 2-Bromopropen Amido Hydrophobes Figure 4.3. Average Number of Millimoles of 2,4-Difluoro-5- Chloropyrimidyl Amino Hydrophobes Grafted onto the Wool Fabric at Different Concentrations Figure 4.4. Average Number of Millimoles of 2-Bromopropen Amido Hydrophobes Grafted onto the Wool Fabric at Different Concentrations Figure 4.5. Bending Length Versus % Application Level of Reactive Hydrophobe (o.w.f.) on Wool Fabric - Warp Side Figure 4.6. Bending Length Versus % Application Level of Reactive Hydrophobe (o.w.f.) on Wool Fabric - Weft Side Figure 4. 7. Yellowness Index (YIE) Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool

Figure 4.8. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Red BF

Figure 4.9. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Pink FF3B

Figure 4.10. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Turquoise G

Figure 4.11. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool, After Dry-Cleaning - Disperse Red BF

Figure 4.12. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool, After Dry-Cleaning - Disperse Pink FF3B

Figure 4.13. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool, After Dry-Cleaning - Disperse Turquoise G Figure 4.14. Light Fastness Values for Hydrophobe Modified Wool Dyed With Disperse Red BF

-xiv- Figure 4.15. Light Fastness Values for Hydrophobe Modified Wool Dyed With Disperse Pink FF3B Figure 4.16. Light Fastness Values for Hydrophobe Modified Wool Dyed With Disperse Turquoise G Figure 4.17.a Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Acilan Direct Blue A Figure 4.17.b Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Carbolan Blue BS Figure 4.17.c Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Neolan Blue 2G Figure 4.17.d Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - lrgalan Grey BL Figure 4.17.e Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Acidol Dark Blue MTR Figure 4.17.f Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Drimalan Blue F-2GL Figure 4.17.g Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Lanasol Blue 3G Figure 4.17 .h Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Procion Navy HE-R Figure 4.18. Colour Difference Between Treated and Untreated Wool Samples - Oxygen Plasma Treated for 10 Minutes Figure 4.19. Plot of Delta E versus Molecular Weight Figure 4.20. Rate of Dye Uptake for Wool Samples Exposed to an Oxygen Plasma for Different Periods of Time Figure 4.21. Colour Difference Between Treated and Untreated Wool Samples for Differing Periods of Treatment Time Figure 4.22. Rate of Dye Uptake for Samples with Different Ratios of Treated: Untreated - Samples Exposed to an Oxygen Plasma for 10 Minutes and Dyed with 1.0% Procion Navy HE-R Figure 4.23. Effect of Different Plasma Modified Areas on the Colour Difference

-xv- List of Tables

Table 1.1. Morphological Components of Wool Fibres (% o.m.f.) Table 1.2. Structure and Amount of Major Amino Acids in Wool Table 2.1. Recommended Temperature and Time of Heat Transfer Printing of Different Textile Fabrics Table 2.2. Reactive Dyes for Wool Table 3.1. Dyes Used for Transfer Printing Table 3.2. The Structural Formulae of Reactive Hydrophobes Used in this Work Table 3.3. Coefficient b Values for Different Hydrophobes Table 3.4. Dyes Used on Plasma Treated Wool Table 4.1. Average Weight Gain ( %) of Wool Samples for each Hydrophobe at Different Concentrations

Table 4.2. Average Number of Moles of Reactive Hydrophobe (xl04 ) Grafted onto the Wool Fabric at Different Concentrations Table 4.3. The IOR Values of Amines Used Table 4.4. Yellowness Index (YIE) at Different Application Levels of the Four Reactive Hydrophobes Table 4.5. Light Fastness Values for Hydrophobe Modified Wool which has been Transfer Printed with Three Different Disperse Dyes Table 4.6. Colour Difference (~E) Between Untreated and Treated Wool Samples Dyed at 0.2 % and 1.0% Dye Concentrations - Treatment: Exposure to an Oxygen Plasma for 10 Minutes Table 4.7. Comparison of Molecular Weight and ~E Table 4.8. Wash Fastness Ratings for Both Untreated and Ten Minute Oxygen Plasma Treated Wool Samples

-xvi- Table 4.9. Light Fastness Ratings for Both Untreated and Ten Minute Oxygen Plasma Treated Wool Samples Table 4.10. Colour Difference (8.E) Between Untreated and Treated Wool Samples for Differing Periods of Treatment Time - Treatment: Exposure to an Oxygen Plasma and Dyed with a 1.0% Dye Concentration Table 4.11. Wash Fastness and Light Fastness Ratings for Oxygen Plasma Treated Wool Dyed with 1.0% Procion Navy HE-R Table 4.12. Colour Difference Values for Different Ratios of Treated to Untreated Sample Size

-xvn- List ofAbbreviations

AB 2-Bromopropenanilide AP N-2,4-Difluoro-5-Chloropyrimidyl Aniline AOX Absorbable Organic Halogen Compounds Ar Phenyl AS Australian Standard C Celcius CD Corona Discharge Cl Colour Index

CSIRO Commonwealth Scientific and Industrial Research Organisation ~E Colour Difference GD Glow Discharge HTP Heat-Transfer Printing IR Infrared IOR Inorganity-Organity Ratio IWS International Wool Secretariat K Adsorption Coefficient kHz Kilohertz kPa Kilopascals kV Kilovolts KIS Ratio of K to S LR Liquor Ratio LTP Low Temperature Plasma MAP N-2,4-Difluoro-5-Chloropyrimidyl p-Toluidine MW Molecular Weight NNB N-1-N aphthyl-2-Bromopropenamide Nf-(1)- 1-Naphthyl

-xviii- nm Nanometers µm Micrometers o.w.f. Weight of Fibre p 2,4-Difluoro-5-Chloropyrimidyl PERC Perchloroethylene R Side Chain of Amino Acids RF Radio frequency r.m.m. Relative Molecular Mass THP Tris (Hydroxymethyl) Phosphine THPC Tetrakis (Hydroxymethyl) Phosphonium Chloride TLC Thin Layer Chromatography UV Ultraviolet WG Weight Gain WRONZ Wool Research Organisation of New Zealand X Reactive Group XYZ The CIE Tristimulus Values YI Yellowness Index

-xix- Chapter One

INTRODUCTION

1.1. Preface

The advent of a whole range of technologies, from 'drive-thru' fast food, to 'E-mail' for instant interactive communication by computer, challenges any industry with the fact that consumers are demanding faster and faster processes for the goods and services they buy.

The textile industry has not escaped this societal trend, and as a consequence, it has necessitated that producers have an ability to respond quickly to the demands of the consumer. In order to meet these increasing demands for quick-response, many textile processes have had to be modified. These modifications include a move away from batch processing (where possible), in favour of continuous processing, increased automation, reduced operator dependency, and both physical and chemical modifications of the textile substrate.

The application of colour to wool, whether it be by dyeing or printing, presently poses a limitation to quick-response. Many of the technologies available are time consuming, and are not satisfying the demands of the consumer.

-1- Chapter One Introduction

epicuticle exocuticle

low-S high-S nuclear proteins proteins remnant r··high-tyr

left- right-. I handed metrill handed coiled-coil <-helill rope microlibril macrolibril cortell• I I I 2 7 200 2000 20000nm

Figure 1.1. Schematic Diagram of the Morphological Components of a Fine Wool Fibre

Cell membrane complex

Cortical cells

Figure 1.2. Simplified Schematic Diagram of the Cuticle and Cortex of Wool Chapter One Introduction

The aim of this work was to develop new and improved methods for applying colour and patterned effects to wool, very quickly. In order to achieve this aim, several reviews are necessary. These include a comprehensive understanding of the following: wool's morphological structure, the chemistry of wool, and the chemical reactions of wool. A brief overview of the technologies that are presently available for applying colour and patterned effects to wool is also essential.

1.2. The Morphological Structure of Wool

Research has shown that wool fibres are composed of two types of cells: the cells of the external cuticle (cuticle cells), and those of the internal cortex (cortical cells). Figure I. I. 111 clearly shows how the cuticle cells completely encase the inner cortical cells. In addition to these two types of cells there is the presence of a cell membrane complex. (Figure I .2.) 111 It is considered to be of particular importance because it constitutes the only continuous phase in wool.

1.2.1. The Cuticle

The outermost surface of the wool fibre is comprised of cuticle cells, and it is these cells that are responsible for important properties such as felting behaviour, 12•31 wettability, 12•4•51 and tactile properties.'21 Approximately 10% of the whole fibre 161 consists of cuticle cells, and they range in thickness from 0.3 to 0.5µm. The cells overlap and interlock with each other like tiles on a roof, with the exposed edges pointing towards the tip of the fibre.

-2- Chapter One Introduction

Epicuticle (12% half-cystine)

\ Exocuticle-'A' · (35% half-cystine)

Figure 1.3. Schematic Diagram of Wool Cuticle Chapter One Introduction

Wool cuticle cells have three distinct layers, 171 namely the epicuticle, exocuticle, and endocuticle. These layers are shown schematically in Figure 1.3. The epicuticle of wool is strongly hydrophobic in character and, as a

result, forms a resistant barrier to the penetration of dyes. 18•91 The exocuticle is the layer of keratinous protein immediately below the epicuticle, and it is believed to contain the majority of the cystine content of the cuticle. 1101 The endocuticle is a well defined layer lying below the exocuticleP·111 The cell membrane complex surrounds the cortical cells and, in so doing, separates the individual cortical cells. It is believed to be derived from material left over from the developing cell. 17•121 It has a relatively low cystine content, and hence is more susceptible than the exocuticle to chemical attack.

1.2.2. The Cortex

The remaining 90% of the merino wool fibre, the cortex, has a bilateral structure, and can be further subdivided into two parts: the orthocortex and paracortex. Due to the differences in the organisation of the micro fibrils and the relative amounts of matrix proteins between the orthocortex and the paracortex, the orthocortex is more reactive chemically and more accessible to dyes. 1131 Ley 191 has argued that the paracortex consists of a heavily crosslinked matrix, which renders it relatively inaccessible to dyes or chemical reactants.

The cells of the cortex contain around 13% of nonkeratinous proteinsY1 The composition of the nonkeratinous material in the cortical cells is believed to be similar, in many respects, to the endocuticular material described in Section 1.2.1. 171 The manner in which the nonkeratinous material is distributed within the cell helps us to distinguish between

-3- Chapter One Introduction

Non- Non- Component Keratinous Keratinous Protein Proteins Proteins Matter

Cuticle (a ) - exocuticle 6.4 - - - endocuticle - 3.6 -

Cortex (b) - microfibrils 35.6 - - - matrix 38.5 - - - nuclear remnants and intermacrofi bri 11 ar material - 12.6 -

Cell Membrane Complex (c) - soluble proteins from membrane complex - 1.0 -

- resistant membrane (d) 1.5 - - - lipids - - 0.8

Total 82.0 17.2 0.8

Table 1.1. Morphological Components of Wool Fibres(% o.m.f.)

Note: (a) Total Cuticle I 0%, (b) Total Cortex 86.7%, (c) Total Cell Membrane Complex 3.3%, (d) Including the Epicuticle 0.1% . Chapter One Introduction

orthocortical and paracortical cells. 114•151 Paracortical cells are generally more clearly outlined than those of the orthocortex, with the nonkeratinous material concentrated in prominent regions of variable size, called nuclear remnants. (Refer Figure 1.1.) Nuclear remnants are less apparent in the cells of the orthocortex because the nonkeratinous material is distributed rather than being concentrated in specific regions.

1.2.3. The Cell Membrane Complex

In recent times, the cell membrane complex has been the subject of a great deal of research, despite its small presence in the total mass of wool. This is primarily because it is known to have a considerable influence on both the chemical and mechanical properties of the fibre. 116-181 It is now accepted that the cell membrane complex is a region of relatively low mechanical strength. 117•181 The strength of this region is further decreased by prolonged dyeing at low pH or chemical finishing operations, 116•19-211 but is actually increased by extraction with certain organic solvents. The morphological components of wool fibres are listed in Table 1.1.

1.3. The Chemistry of Wool

The experimental work outlined in this thesis is primarily concerned with the modification of both the chemical and physical components of the wool fibre, so as to obtain a quick-response technique for late stage colouration. In order to devise these modifications, a comprehensive understanding of the reactions of wool is essential. It is, therefore, highly appropriate to review the present state of knowledge regarding the chemistry of wool.

-4- Chapter One Introduction

Amino Acids Structure of Side-Chain Mol% Nature of (-R) r2s, 261 Side-Chain

Aspartic Acid - CH2 - C - OH 6.4 Acidic II 0

Glutamic Acid - CH2CH2- C- OH 11.9 Acidic II 0

Histidine ~CH-NH 0.9 Basic -CH2 -C1/ I '----- N =CH

H NH Basic Arginine I II 6.8 -CH2CH2CH2NC'-. NH2

Basic Lysine - CH2CH2CH2CH2NH2 3.1

Sulphur-Containing Methionine - CH2CH2 - S - CH3 0.5

Sulphur- Containing Cystine - CH2 - S - S - CH2 - 10.5

0.5 Heterocyclic Tryptophan -CH2w

NH

Heterocyclic Proline H2C--CH2 5.9 (Complete I I formula) H2C CHCOOH V NH

Table 1.2. Continued Chapter One Introduction

Amino Acid Structure of Side- Mol% Nature of Chain (-R) [25,261 Side-Chain

Glycine -H 8.6 Hydrogen

Alanine -CH3 5.3 Hydrocarbon

Phenylanaline 2.9 Hydrocarbon -CH2--@

Valine _..-CH3 5.5 Hydrocarbon -CH -...... CH3

Leucine _..-CH3 7.7 Hydrocarbon -CH2CH -...... CH3

Isoleucine ----CH] 3.1 Hydrocarbon -CH --- CH2CH3 Serine -CH20H 10.3 Polar

Threonine /OH 6.5 Polar -CH "- CH3

Tyrosine 4.0 Polar -CH2--@0H

Table 1.2. Structure and Amount of Major Amino Acids in Wool Chapter One Introduction

1.3.1. The Chemical Composition of Wool

The chemical composition of the wool fibre is equally as complex as its morphological structure. It is composed of highly crosslinked keratin proteins, and when it is hydrolysed with either acid or alkali, it yields a mixture of 18 a-amino acids of the general formula H2N-CHR­ COOH.122'231 (Refer Figure 1.4.)

Figure 1.4. General Formula of a-Amino Acids

From this general formula, it can be seen that the common groups in amino acids are a carboxyl group (-COOH) which is acidic, an amino group (­ NH2) which is basic, and a hydrogen atom. Variations in the structures of these amino acids occur in the side chains (-R). Risa group of atoms and it may be aliphatic or aromatic, hydroxylic, acidic, basic, heterocyclic, or sulphur-containing. Only about 20 different R groups are presently known to occur in proteins. The structure, nature of the side-chain, and the amount of the major amino acids in wool (expressed in grams per 100g of dry wool), are given in Table 1.2.

Any two amino acids can condense together to form a dipeptide by splitting off a molecule of water from the -NH2 group of one amino acid and the -COOH group of another.'261 (Refer Figure 1.5.)

-5- Chapter One Introduction

H R1 H R2 \I \/ C + C /\ /\ COOH CONH COOH Figure 1.5. Condensation of Two Amino Acids to Form a Di peptide

This dipeptide can further condense at each end with other amino acids. As more and more amino acids condense, the molecular chain increases, and it quickly becomes a polypeptide. It is this polypeptide chain that forms the basis of the protein structure. Figure 1.6. gives a simplified representation of a polypeptide chain, consisting of five different amino acids.

H R2 H R4 H I I I I I -NH-C-CO-NH-C-CO-NH-C-CO-NH-C-CO-NH-C-C0-

1 I I R1 H R3 H Rs

Figure 1.6. A Typical Segment of a Protein Chain

To fully comprehend the reactivity of wool, the individual character of each side chain (-R) of the amino acids needs to be studied. For ease of discussion, all the side chains can be divided into two distinct groups according to their polarity; i.e. they are either hydrophobic or hydrophilic in nature.

-6- Chapter One Introduction

1.3.2. Hydrophobic Side Chains

Glycine, alanine, phenylalanine, valine, leucine and isoleucine, all have R groups which are non-polar. Consequently, they have low affinity for polar molecules such as water, acids, alkalis and salts, but have affinity for non­ polar molecules such as hydrocarbons. With the exception of glycine, they are all made up of hydrocarbons, and they all provide hydrophobic side groups in the protein chain.

1.3.3. Hydrophilic Side Chains

All of the hydrophilic side chains are polar. Within this group, the side chains can be further divided into acids, neutral or basic groups.

1.3.3.1. The Amino Acids with Acidic R Groups

This group comprises glutamic acid and aspartic acid. Both of these amino acids also occur in a modified form in wool, where -NH2 replaces the -OH group of the carboxylic acid. Consequently, the -R groups of both glutamic and aspartic acid become -CH2CH2CONH2 (glutamine), and -CH2CONH2 (asparagine). This is considered to be the amide form of the acids. Aspartic acid in wool is predominantly found in its amide form whereas glutamic acid is mostly in the carboxylic acid form. 127-291

1.3.3.2. The Amino Acids with Neutral R Groups

There are many amino acids which make up this group. Within this group, further subdivisions can be made.

-7- Chapter One Introduction

[1] Serine, threonine and tyrosine. These three amino acids can be grouped together because all three have -R groups which contain hydroxyl groups. They all attract polar molecules due to the presence of polar side groups in the protein chain.

[2] Tryptophan. This amino acid has a heterocyclic ring in its - Rgroup.

[3] Proline. This amino acid is quite unique. It does not have the normal side chain -R which projects from the main polypeptide chain. The five-membered ring was formed during the biosynthesis of the fibre.

[4] Methionine and cystine. These two ammo acids are characterised by the presence of sulphur. Of the two, cystine is of most interest, because of its special significance in the chemistry of wool. It makes up approximately 10% of wool, and is largely responsible for the high sulphur content of wool.

1.3.3.3. The Amino Acids with Basic R Groups

This group comprises histidine, argmme and lysine. All three of these amino acid groups in the protein chain are protonated at low pH and hence can attach acid dyes. In addition, reactive dyes can be covalently attached to the side chains of histidine and lysine residues. It is now appropriate to review the chemical reactions which wool can undertake.

-8- Chapter One Introduction

1.4. Reactions of Wool

It is generally recognised that wool fibres, by their nature and origin, are among the most heterogeneous materials to be subjected to physical and chemical studies. 1301 The majority of protein reactions depend on the nucleophilicity of the side chain groups or on their ability to undergo oxidation or reduction. These reactions have been the subject of several valuable reviews 1311 and books 1321 , and have been outlined below.

1.4.1. Oxidation

The amino acid residues cystine, cysteine, methionine and tryptophan are the most susceptible to oxidation in wool and other proteins. Of these, the cystine residues are the most abundant. Consequently, the most significant modifications of the wool occur when cystine is oxidised. Complete oxidation of cystine residues results in disruption of cross linking and the formation of cysteic acid residues as the final product. Intermediate oxidation products may result under controlled conditions of oxidation as shown in the reactions in Figure 1. 7.

[O] [O] RSSR---RSOSR --•

CH2 I Where: R = Wool - NH - CH - CO - Wool

Figure 1.7. Oxidation of Cystine

-9- Chapter One Introduction

These intermediate oxidation products of cystine may themselves behave as reactive centres, rapidly reacting with thiols to form unsymmetrical disulphide derivatives. Large amounts of thiol (up to 600 µM/g) may be bound to mildly oxidised wool in this way. 1321

The main types of agents used for oxidising wool include peroxyacids, hydrogen peroxide, chlorine, oxy-chlorine or oxy-bromine compounds, N­ chloro or N-bromo compounds and permanganate.'321 Although oxidising agents react predominantly with the thiol and disulphide groups in wool, they may also modify other groups. For example, oxidants generally convert the sulphide group of the methionine residue to the corresponding sulphoxide or sulphone. Tryptophan residues are also converted to N­ formylkynurenine residues and other products.

1.4.2. Reduction

The behaviour of the disulphide bonds has been the predominant focus of studies concerning the effects of reducing agents on keratin fibres. The cystine content and the large number of disulphide bonds is what makes keratin fibres easily distinguishable. It is the disulphide bonds that are prone to reduction. Treatment of wool with reducing agents converts disulphide bonds to thiol groups, each cystine residue forming two cysteine residues. 1331

[H) RSSR --• RSH + RSH Where: R = Wool - NH - CH - CO - Wool I CH2 I

Figure 1.8. Reduction of Wool

-10- Chapter One Introduction

Although many reagents are capable of reducing disulphides, few have the required reactivity and specificity under conditions which do not cause protein damage. The most common classes of reducing agents for wool are thiols, phosphines and sulphites. 1331

1.4.2.1. Reduction with Thiols

Many different thiols have been used to reduce wool. Thioglycollic acid, 2- hydroxyethanethiol (mercaptoethanol) and toluene-ro-thiol (benzylmercap­ tan) are among the most useful. 1331 Reaction takes place via two reversible nucleophilic displacement reactions. 1341

NH co NH co I I I I HCCH2S - SCH2CH + RSH +----+ HCCH2S-SR + HS-CH2CH I I I I co NH co NH I I I I

NH NH I I HCCH2 - S - S - R + RSH 411 ., HCCH2SH + R-S-S-R I I co co I I

Figure 1.9. Reduction of Wool with Thiols

-11- Chapter One Introduction

1.4.2.2. Reduction with Phosphines

The most effective tertiary phosphine for reducing wool is the water­ insoluble tri-n-butylphosphine. 135.361 It reduces the disulphide groups of wool to thiol groups in near-quantitative yield at room temperature in the pH range l-8; no fibre disruption occurs under these conditions. 1331 The possible mechanism for the reduction of disulphides by phosphines involves an initial nucleophilic attack at a sulphur atom by the tertiary phosphine, followed by a nucleophilic displacement. 1301

NH CO NH co I I I I HCCH2 - S - S - CH2CH + I I co NH I I

co I

Figure 1.10. Reduction of Wool with Phosphines

This reaction is irreversible, unlike that between disulphides and thiols. Consequently only a small excess of phosphine is required for complete

-12- Chapter One Introduction reduction. A further advantage of phosphines as reductants for wool is that they react with alkylating agents much less rapidly than do thiols. Therefore, it is possible to treat wool with a phosphine and an alkylating agent, such as chloroacetate, in the same solution. 1371 This gives both reduced and alkylated wool in the one step. Other tertiary phosphines useful for reducing disulphide bonds in keratin include tris (hydroxymethyl) phosphine (THP) dissociated from tetrakis (hydroxymethyl) phosphonium chloride (THPC). l3S.39l

1.4.2.3. Reduction with Sulphites

Sodium bisulphite can also be used to reduce the disulphide bond in wool. Cleavage of the disulphide bond in wool at equilibrium reaches a maximum at about pH 4.6 in various buffer solutions and reaction is greatly increased if aqueous alcohol solutions are used. Reduction by sodium bisulphite of the disulphide bond of wool produces a thiol and S-sulphocysteine.

NH co NH co I I

HCCH2 - S - S -CH2CH + NaHSO3 <=:> HCCH2SH + NaOSO2S - CH2 - CH I I co NH co NH I I I I

Figure 1.11. Sulphitolysis of Wool

-13- Chapter One Introduction

1.4.3. Hydrolysis

Hydrolysis of the peptide chain involves a nucleophilic substitution reaction, in which the -NH- group is replaced by -OH. Under acid conditions, hydrolysis involves attack by the water molecule on the protonated amide while, under alkaline conditions, hydrolysis involves attack by the strongly nucleophilic hydroxyl ion on the amide itself. Martin1401 and O'Connor1411 have agreed that protonation of the carbonyl oxygen, rather than the amide nitrogen, is predominant during the acid hydrolysis of amides.

1.4.3.1. Reaction with Acid

The addition of acid to wool results in the progressive conversion of carboxylate anions to carboxylic acid groups. In this case, wool behaves as an ampholyte and equilibrium is reached for each pH condition.

Figure 1.12. Wool Behaves as an Ampholyte

Amide bonds are the most acid-labile groups in wool. Thus, in the acid hydrolysis of wool, the amide groups are attacked first by the acid, then followed by the hydrolysis of certain amino acids in the main chain.

-14- Chapter One Introduction

Degradation of wool by the acid hydrolysis of peptide bonds is indicated by the loss of tensile strength. Four reactions can occur during the treatment of wool with acids: 1421

(1) Cleavage of amino acid side chains, such as sensitive glutamine. (2) Cleavage of peptide bonds. After aspartic acid, glycine and serine are the most readily released amino acids.

(3) N ~ 0 migration (acyl shift) at serine and threonine residues. ( 4) Disulphide interchange.

1.4.3.2. Reaction with Alkali

The technical problems associated with alkaline hydrolysis are more significant than with acid hydrolysis. It is known to be more destructive and less selective. All proteins are vulnerable to degradation by alkali due to the hydrolysis of peptide bonds and amide side chains. The cystine residues in wool are also particularly prone to alkali damage since disulphide bonds readily undergo reaction with alkali to produce the active intermediates dehydroalanine, bound cysteinate ions and sulphur atoms.

Hydrolysis of proteins with alkali results in extensive decomposition of the serine, threonine, cysteine, cystine and arginine residues. However, tryptophan residue is relatively stable to alkali, and hydrolysis with sodium or barium hydroxide has been recommended as a preliminary step to the analysis of tryptophan in wool 1431 and other proteins. Lanthionine is the major product formed by the reaction of wool with alkali, since cystine is abundant in wool.

-15- Chapter One Introduction

1.4.4. Esterification

Esterification is the most popular method for modifying carboxylic acids in general, and it is also the most satisfactory for modifying carboxyl groups in wool. Wool has a relatively high carboxylic acid content (800µmol.g- 1) provided by the side chains of aspartic and glutamic acids, as well as by terminal carboxyl groups. 1441 Esterification of these carboxylic acid groups is achieved by nucleophilic attack by Ro- on the carbonyl carbon of the carboxylic acid residues, resulting in the displacement of an OH-.

I I HC(CH2)1,2 COOH + RO- ~ HC(CH2)1,2 COOR + OH- I I

Figure 1.13. Acting as an Acceptor in Nucleophilic Substitution

In some cases esterification may occur by nucleophilic attack by the -Coo­ of the protein on suitable reagents, such as epoxides, active halogen containing compounds or dimethyl sulphates.

I HC(CH2)1,2 coo- + R-L ~ I

Figure 1.14. Acting as a Donor in Nucleophilic Substitution

The mechanical stability of wool is drastically reduced by esterification. 1451 This is by no means surprising, as it is consistent with evidence that shows

-16- Chapter One Introduction

\ \ NH NH I I H2N(CH2)4CH RCONH(CH2)4CH \ \ co co I I HN NH HN NCOR \ II \ II HC(CH2)3NHC HC(CH2)3NHC I \ I \ OC NH2 OC NH2 \ \ NH HN~ I RCON ~H \_O,rCH2CH \_oJ- CH2CH N \ N \ co co I I HN HN \ \ HCCH2OH HCCH2OOCR I I oc oc \ \ HO NH RCOO NH I i I i CH3CHCH CH3CHCH \ \ co co I I HN HN \ \ H~CH2@-0H H~CH2@-00CR oc oc \ \ NH NH I I HSCH2CH RCOSCH2CH \ \ co co I I

Figure 1.16. Some of the Reactions Which May Occur During the Acylation of Proteins Chapter One Introduction the importance of carboxyl groups (or their anions) in stabilising the wool fibre. The resultant removal of carboxylate anions increases the uptake of acid dyes by wool, although this dye assist effect is not practical, as wool loses a substantial degree of strength on esterification. The main types of reagent used for esterifying wool include alcohols, epoxides, carbodi-imides, diazo-methanes, ethyl chloro-formates, methyl halides and dimethyl sulphates.

1.4.5. Acylation

Four main types of reagent have been used for acylating wool, namely, acid anhydrides, acid chlorides, active esters and active amides. 1441 The reaction involves attack by a nucleophilic residue of wool (NUH-) at the electron deficient carbon atom of the acylating agent, as can be seen in Figure 1.15.

o· 0 - 0- - 0 ( 11 II R- C - L+ :NuH - W <=:> R- C - L <=:> R - C - L => R - C - Nu - W + L. 3+~ I I Nu+H-W Nu-W - - - -

Where: W = Wool, L = Leaving Group, and Nu = Nucleophilic Group in Wool

Figure 1.15. Acylation of Wool

In principle the lysine, arginine, histidine, serine, threonine, tyrosine and cysteine residues are all capable of being acylated. (Refer Figure 1.16. t 41

-17- Chapter One Introduction

Asquith1301 emphasised two principles m formulating conditions for acylation:

(1) Nucleophiles are more effective in their unprotonated forms such as RNH2, Aro-, RS-, hence a higher reactivity of the nucleophile is usually associated with a low pK.

(2) Greater selectivity during acetylation of a nucleophile is often observed by using a highly reactive acylating agent at a low pH or a weak acylating agent at a high pH.

The acylating agent typically undergoes nucleophilic substitution where the leaving group ( e.g. -OOCR) is replaced by a basic amino group of wool

( :NH2-Wool). 1461 The reaction consists of two steps:

(1) addition of the nucleophile to the carbonyl group, and, (2) elimination of the leaving group.

The ease with which the leaving group (:L) is lost depends upon its basicity; the weaker the base, the better the leaving group.

Acylation alters the balance of electrostatic charges on the wool fibre, replaces hydrogen bond donors with acceptors, and introduces additional hydrophobic interactions. The introduction of large amounts of bulky acyl groups may convert wool from a hydrophilic to a partly hydrophobic fibre. So large numbers of bulky acyl groups are believed to be largely responsible for the dramatic increase in the resistance of wool to acids and alkalis. Acylated wool has a much lower basic group content than untreated wool, and thus weakly resists the uptake of acid dyes. The introduction of acidic groups, on the other hand, is known to provide stronger acid dye resist affects.

-18- Chapter One Introduction

1.4.6. Alkylation and Arylation

Many different functional side-chains in wool and other proteins can be modified by alkylation or arylation. Cysteine, lysine, histidine, methionine, serine, threonine, tyrosine, aspartic acid, and glutamic acid residues are all prone to attack, although there are large differences in their reactivities. Of these, cysteine residues are the most reactive. 1471 The thiol groups in reduced wool are reconverted rapidly to disulfide groups by oxidation in air. The autoxidation can be prevented by blocking the thiol groups, generally by alkylation. 1331 Figure 1.17. illustrates this reaction.

W- :NuH

Where: W=Wool

Figure 1.17. Alkylation of Wool

Treatment with acrylonitrile in the presence of sodium hydroxide causes a substantial increase in the rate of uptake of both acidic and basic dyes. 1481 A similar effect is produced if wool is first treated with a solution containing sodium bisulphite and urea, and then exposed to acrylonitrile in the presence of catalytic amounts of potassium cyanide or acetic acid. 1491

-19- Chapter Two

QUICK-RESPONSE METHODS

2.1. Conventional Methods of Applying Colour to Wool

Before considering the possibilities of developing a quick-response technology, it is essential to examine the technologies that presently exist for the application of colour to wool. For ease of discussion, these technologies have been briefly outlined and considered in one of two categories; dyeing or printing.

2.1.1. Dyeing Technologies

The technology that is available today enables wool to be dyed at almost every stage in the textile pipeline. These stages include: loose stock, top, yam-hank, yam-package, piece and garment dyeing.

2.1.1.1. Loose Stock Dyeing

Various types of machines are used for dyeing wool in loose stock form. These include conical pan, pear-shaped and radial flow machines. In the first two types of machine, the liquor is pumped through the pack of wool, which is packed relatively loosely in the container. This loose packing

-20- Chapter Two Quick-Response Methods results in a relatively low pressure requirement to produce adequate flow and penetration of the dye liquor through the pack. Unfortunately, productivity is low, however, damage to the wool fibre is minimal. 1501

In the radial flow machines, a cage with a central perforated column accommodates the loose wool, which is usually press-packed into the cage by stamper loading to give a density of approximately 0.25gcm-3•1501 The packed cage is loaded into a large steel container or kier, and dye liquor is circulated at a high rate to ensure level dyeing. Unfortunately, this method increases the degree of fibre damage due to the stamper loading.

In order to reduce the mechanical damage during loose stock dyeing, the WRONZ Soft Flo System was developed by the Wool Research Organisation of New Zealand. In this system, fibre damage is minimised by dyeing at a constant minimum flow pressure throughout the entire dyeing cycle sufficient to give level dyeing, but with reduced mechanical damage to the wool. 1501

2.1.1.2. Top-Dyeing

Wool tops are generally dyed in radial flow machines, the same as outlined in Section 2.1.1.1., but with a different material carrier. The trend in wool top dyeing is to process bumps instead of balled tops. A bump top is a package made by press-packing layers of coiled sliver whereas a ball top is a cross-wound self supporting package of combed sliver produced on the worsted system. 1511

Although bump tops of 5 to 22kg are dyed, those above 10kg are difficult to handle manually and are normally only dyed in fully automated dyehouses. Bump top dyeing has the advantage of eliminating the re-balling process and

-21- Chapter Two Quick-Response Methods bumps of the correct weight for dyeing may be supplied directly from the comber. Additionally, the higher weight of bumps, in comparison with ball tops, means that greater machine loading and therefore process efficiency can be achieved with bumps. 1521

2.1.1.3. Yarn-Package Dyeing

Yam-package dyeing provides the textile industry with an opportunity to colour yam at the latest possible stage prior to fabric manufacture. It is being increasingly used in the wool industry, for the production of colour woven fabrics. It also provides greater flexibility of design than top dyeing, since batch sizes can be varied more widely.

Three basic types of machinery are currently being used for the package­ dyeing of wool yams: horizontal-spindle, vertical-spindle and tube-type machines. 1501

Horizontal-Spindle Machines: There are two main types. A typical example of the first is the Pegg GSH which is usually used for dyeing high­ bulk yams, which are soft-wound to give a low-density package. The Thies Eco-bloc machine is representative of the second type of horizontal-spindle machine. It is a horizontal autoclave, into which is wheeled the carrier containing the horizontal-spindles. 1501 As the name implies, the yam packages are loaded into each of these two machines on horizontal-spindles.

Vertical-Spindle Machines: These are the most commonly available and widely used machines for package dyeing. The packages are loaded using overhead hoists and placed on vertical-spindles. Press-packing is possible, with the resultant advantage of higher payloads and minimum liquor-to­ goods ratio, with subsequent savings in resources and energy.

-22- Chapter Two Quick-Response Methods

Tube-Type Machines: There are two types of tube machine. One has vertical spindles on to which tubes are lowered ( e.g. Flainox Economy Sistem F-1/AT-140) and the other has horizontal tubes into which full spindles are loaded (e.g. Ohern APl/O). Both types can be operated at liquor-to-wool ratios as low as 4: 1, enabling reductions in energy, water, effluent and chemicals to be made. The other main advantages of this type of machine are: (i) The machines are installed at floor level without the need for pits, platforms or overhead cranes. (ii) Circulation of dye liquor through the yarn is increased due to the lower volume of dye liquor. (iii) Multiple-tube machines are capable of having tubes blocked off. (iv) Can be operated at liquor-to-wool ratios as low as 4: 1. (v) Loading and unloading is much simpler and hence down-time

of the machines between batches is significantly reduced. [SOJ

2.1.1.4. Yarn-Hank Dyeing

Yam for carpets, hand knitting and machine knitting is still predominantly dyed in hank form, although there are developments taking place which will allow these yarns to be package-dyed.

Most carpet yarn is dyed on single-stick Hussong machines. [SOJ The yam is suspended on the stick and the dye liquor is circulated through it. A recent development has seen the introduction of a second stick at the bottom of the hank, which prevents the mass being lifted by the dye liquor and allows a greater rate of flow to be used without severe tangling.

A more recent development is the cabinet hank dyeing machine. In these machines the hank carrier, mounted on a trolley, is loaded outside the dyeing

-23- Chapter Two Quick-Response Methods cabinet and is then wheeled into the cabinet for dyeing. At least two hank carriers are required for each cabinet, enabling the operator to load and unload the carrier whilst the alternate lot is being dyed. This ensures that down-time is kept to a minimum.

2.1.1.5. Piece Dyeing

Wool fabrics have been traditionally dyed in open winch machines, which, despite their limitations, are still successfully used for some wool and wool blend qualities. However, developments in piece dyeing machinery have ensured that wool fabrics of all types can now be dyed level, and retain good surface appearance. Most modem overflow/jet piece dyeing machines operate at lower liquor to wool ratios than traditional winches and are equipped with process controllers. These factors lead to greater shade reproducibility and therefore improved production efficiency. Good levelness is achieved because of the high level of liquor/fabric interchange that is possible in these machines, when compared with winches. 1521

Both woollen and worsted fabrics can be piece-dyed on beam dyeing machines. The beam dyeing process is a form of package dyeing in which the fabric is dyed in open width on a perforated cylinder. Atmospheric- and high-temperature machines are available, the direction of the liquor flow can be reversed and a high degree of automation can be achieved. 1501

2.1.1.6. Garment Dyeing

Fully fashioned garments and body blanks for the cut-and-sew industry are increasingly dyed in garment form, as this allows the supplier to delay the

-24- Chapter Two Quick-Response Methods choice of shade until the latest possible time before the garments appear on retail counters. 1501

Side- and overhead-paddle machines have been traditionally used for dyeing and finishing wool knitwear. Such machines are labour-intensive because the degree of process control is limited: all additions must be made manually, and loading and unloading are time-consuming. 1501

Since the late 1970's the type of machinery used in wool garment dyehouses has changed, with the introduction of front-loading rotary-drum machines. These machines operate at a much lower liquor-to-goods ratio than the side­ paddle machines, and consequently offer cost savings through reduced water, energy and manpower requirements. 1501

2.1.2. Printing Technologies

There are four mam technologies that are presently available on a commercial scale for the printing of wool. These are direct, discharge, resist and Vigoureux printing. The first three are designed to be applied to the wool in fabric form, whereas Vigoureux printing is specifically applied to the wool when it is in sliver form. Below is a brief summary of these technologies.

2.1.2.1. Direct Printing

Direct printing represents the most straightforward and widely used printing style on wool,even though prechlorination is usually necessary. It involves

-25- Chapter Two Quick-Response Methods the use of a flat-bed or rotary screen printer, screens which have had the designs etched onto them, a squeegee, a drying oven, and selected dyes and chemicals. The most widely used dyes are the nonreactives (i.e. acid milling and metal-complex). These dyes are favoured by the wool printer, because between them they provide economy, good fastness, high solubility, and bright shades. Reactive dyes are also used for wool printing, but their use is mainly limited to when very high wet fastness standards are required. These dyes also offer other advantages such as better solubility than acid dyes, and a shorter steaming time. The use of pigments is not generally encountered in wool printing due to the considerable modification of the fabric handle by the binders. 1531

After printing and drying, the dye is deposited on the fibre surface, within a thickener film, in a highly aggregated form. A steaming operation is therefore necessary to swell the thickener film and dissolve the dye, swell the wool fibre to allow penetration of the dye, and elevate the temperature of the fibre to effect fixation of the dye. Typical steaming times are 10-15 minutes for reactive dyes, and 30-45 minutes for metal-complex and acid milling dyes. 1531

Fallowing steaming is a wash-off step. The aim of this process is to remove thickeners, chemicals and unfixed dyes. This has to be achieved without detriment to the goods and without staining of unprinted or pale-coloured areas.

2.1.2.2. Discharge Printing

Classical discharge printing is widely practised despite its many drawbacks and problems. In discharge printing, a predyed fabric is printed with a reducing agent which destroys the ground shade dyeing. The result is a

-26- Chapter Two Quick-Response Methods pattern with great clarity, sharpness and fit, and with strongly contrasting grounds. Unfortunately, little has been published during the last decade on the discharge printing of wool, reflecting perhaps the difficulties involved in the process. 1531

Discharge printing involves the actual chemical destruction of the original dye in the printed areas. This chemical destruction requires the use of a reducing agent and sodium and zinc formaldehyde sulphoxylates are the most commonly used. Once this chemical is printed onto the fabric, it should be dried as quickly as possible, but not at too high a temperature. 1541 Dyes can be selected for their stability to the reductive discharge chemicals. Such dyes will achieve illuminated discharge prints.

Steaming of the fabric is then carried out for 10-20 minutes at l00-120°C, with air-free steam being essential. It is also important that the required steaming temperature is attained as quickly as possible, since the formaldehyde sulphoxylate begins to break down at about 50-60°C. Finally, washing-off is carried out under mild conditions, as the dyes used for coloured discharge generally possess poor wet fastness properties. 1531

2.1.2.3. Resist Printing

Batik is an example of traditional resist printing. The design is printed on the fabric in wax or other dye resistant paste, and the fabric is then dyed. After dyeing, the resist is then removed, leaving the white areas of the design. 1551 Despite using a different processing route, the end result of resist printing is very similar to that of discharge printing. Whilst commonly employed in the traditional printing of cotton, batik printing is not practised on wool.

-27- Chapter Two Quick-Response Methods

Several methods have been suggested for rendering wool nondyeable with acid dyes, the first practical proposition being the use of a reactive resist agent resembling a colourless reactive dye. One such product was Sandospace R from Sandoz, which is a highly reactive water-soluble anionic product. The resist arises both from blocking of reactive amino sites on the fibre, and by anionic repulsion. 1531

2.1.2.4. Vigoureux Printing

The Vigoureux printing process is primarily used to produce a multi-colour or melange effect in quality worsted fabrics for apparel use. It is predominantly used on wool sliver, and very rarely on synthetics. The process consists of the printing of parallel bands at an angle of 30-40° to the direction of the sliver of combed wool. After fixation, washing and drying, the worsted tops are mixed at the gill-box to make a variegated effect. 1561

The ratio of percentage surface printed to percentage surface unprinted is determined by the width of the bands. In order to keep the Vigoureux effect, the maximum relative surface area printed must not exceed 85%. To obtain medium shades, rollers with from 10-25% surface area are used. Pale shades require the use of a fluted roller with a small surface area, ranging from 6-8%.

A steaming of the wool slivers follows immediately after the printing process, without intermediate drying. Up until recently, the autoclave was the most commonly used steamer, which made the process into a batch system. However, recent modifications have resulted in the development of

-28- Chapter Two Quick-Response Methods a continuous system, where the printed sliver travels straight through an open steamer. Following steaming, the slivers are washed in 4-5 wash boxes and then dried. The process is completed by putting the dried and combed wool through the gill-box, where the fibres are drawn, mixed and orientated, and then are wound onto bobbins.

There are a number of factors which determine how much dye will be deposited onto the web of slivers, namely: 1561

- the relative surface area of the impression roller, - the pressure that is applied to the impression roller, - the thickness and quality of the felt, - the viscosity of the paste, and, - the nature of the thickener and the wetting agent used.

This brief summary of dyeing and printing technologies clearly indicates that much has already been done to ensure quick and efficient colouration of wool in its various forms. However, the advancements that have been made so far are by no means complete. The challenge still remains for the textile technologist to further develop these technologies or even create completely new ones. The mounting pressure from the consumer to supply high quality textile goods, at a competitive price, upon demand, will ensure through necessity, that these advancements continue to occur.

The above challenge forms the basis of this thesis. Two specific areas have been examined in detail and these are: firstly, modification of the wool fibre with reactive hydrophobes, and secondly modification with plasma treatment.

-29- Chapter Two Quick-Response Methods

Paper Support + Ink Layer

------+-Cloth

Light Pressure Heavy Pressure &Heat &Heat

Separation

Inefficient Transfer Efficient Transfer

Figure 2.1. Melt-Transfer Printing at Different Pressures Chapter Two Quick-Response Methods

2.2. Transfer Printing

Transfer printing is defined as any process by which a design is transferred from paper to another substrate. 1571 Fundamentally, the process occurs in two stages. The initial stage involves the printing of a selected design onto a special transfer paper. The final stage sees this design on the paper being transferred onto the fabric, using a specific method. This form of printing was first patented in the l 960's by Filatures Prouvost Masurel, 1591 and later, it was successfully adopted for the printing of polyester and triacetate fabrics. There are at present, four distinct transfer printing processes used in practice. These include:

- melt-transfer, - film-release, - wet-transfer, and - heat-transfer (sublimation).

Heat-transfer printing is the most commonly used in industry, and has been used in this work.

2.2.1. Melt-Transfer Printing

In this process, a hard permanent print is applied to the transfer paper with an ink that is wax based. The fabric is then brought into contact with this printed paper, and both heat and pressure are applied. The heat causes the wax to melt, and a partial transfer of the design occurs. The extent to which the molten ink layer is picked up by the fabric depends not only on the temperature, but also on the applied pressure. The effect of using different

pressures is shown diagrammatically in Figure 2.1. 159•601

-30- Chapter Two Quick-Response Methods

~ Paper Release -~------~- Film ~ l______J - ~Ink Layer

Cloth ~ Heat& l Pressure

---~ ---

[ Separation

l Fixation

Figure 2.2. Film-Release Transfer Printing Chapter Two Quick-Response Methods

2.2.2. Film-Release Transfer Printing

This process involves the application of a heat tack resin film to the transfer paper and then, with the use of a pigmented ink containing dye fixing auxiliaries, the design is printed on top. The printed paper is then brought into contact with the fabric, and is heated under pressure. 1591 (see Figure 2.2.) This causes the film to become tacky and it adheres readily to the substrate pressed against it. The design pattern and some of the resin film remain on the fabric when the paper is removed. After this process has taken place, the textile fabric is subjected to a conventional dye fixation step followed by washing. It is during this washing stage that any release film that was transferred onto the fabric is removed, leaving only the dyestuff on the fabric. 159•601

2.2.3. Wet-Transfer Printing

The concept of wet-transfer printing was first introduced by Dawson International in the late 1960's, and was the subject of two patents and publications. 161•621 It was based on the use of transfer papers printed with Lanasol reactive ( cx-bromoacrylamido) dyes, which were brought into contact with the substrate, which had been prepadded with a thickened acid liquor. The mechanism of dye transfer from the paper to the fabric consists of initial dissolution of dye in the water film, migration through the film to the fabric surface and finally absorption and fixation of the dye in the fabric, all of which take place under the combined effects of moisture, temperature, pressure and time of contact. 160•631

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2.2.4. Heat-Transfer Printing

The basic process of heat-transfer printing (HTP) involves the transfer of selected disperse dyes, by sublimation, from preprinted paper to the fabric surface. The paper support is printed with a specially formulated ink containing sublimable dyestuffs. The methods available for paper printing include:

(a) Gravure Printing,164-681

(b) Flexography, 164-66• 69-721 (c) Letterpress and Lithography, 1661 and,

( d) Flat-Bed or Rotary Screen Printing. 165•66•72 -76I

The substrate may be in several forms, but is most commonly found in either a continuous roll of fabric, or in a made-up garment. The disperse dyes which are used all have the ability to sublime within the temperature range of 180°C to 240°C, condense on the fibre surface, and then diffuse into the fibre via the solid state. The entire process occurs without the use of a solvent. The most commonly used substrates are polyester, and polyester blend fabrics. Typical conditions for HTP are:

- temperature, 200-210°C, - duration, 30-40 seconds.

2.3. Factors Influencing the Heat-Transfer Printing Process

2.3.1. Textile Substrate

Not all textile substrates are suitable for HTP as they have low affinity for disperse dyes. Those substrates which are suitable include polyesters,

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cellulose diacetate, cellulose triacetate, polyamides and acrylics. 165•77-801 Of these, polyester and cellulose triacetate exhibit the best wash fastness properties.

Natural fibres such as wool or cotton, having little, if any, affinity for disperse dyes, may be included in blend fabrics, particularly in conjunction with polyester, provided that they do not contribute more than 25-30% to the total fabric weight. 1771

The substrate to be printed must be both chemically and dimensionally stable at the printing temperature. A loss of print definition will result if dimensional changes greater than 2% occur during printing. Therefore, it is essential to ensure dimensional stability either by a prior heat setting process at a temperature slightly above that of printing or by a scouring treatment which allows sufficient structural relaxation to confer heat stability. Scouring also removes spinning and knitting oils which could affect the printing.

The textile substrate should be capable of undergoing morphological changes under transfer conditions. This is a necessity if one is to achieve an increase in free volume and hence obtain diffusion of the dye molecules into the fibre, thus obtaining good depth of colour. Both the swelling of the fibres and the softening of the polymeric chains enhances the diffusion of the dye into the substrate. Natural fibres like wool and cotton do not soften during transfer and, as a result, inhibit the diffusion of dye molecules into these fibres. In addition, water is driven out of these natural fibres due to the high temperatures employed in the HTP process. The absence of water prevents the fibres from swelling and, consequently, inhibits dye diffusion into the fibres. 1801 Therefore, the natural fibres are unsuitable for HTP as they are not capable of undergoing the desired structural changes under the transfer conditions.

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CN

0 N

Bulky Substituent Groups Molecular Weight of Disperse Dye= 393 Good sublimation property. Suitable for transfer printing.

Figure 2.3. Disperse Dye with Bulky Substituent Groups

H '\. 0 0-H ....

.... H-0 0 0 I 0 H

Intramolecular Hydrogen Bonding Intermolecular Hydrogen Bonding

Good Sublimation Property Poor Sublimation Property

Suitable for Transfer Printing Unsuitable for Transfer Printing

Figure 2.4. Disperse Dye Structures Showing Inter and Intra Hydrogen Bonding Chapter Two Quick-Response Methods

2.3.2. Dyestuffs

The ability to vaporise, or sublime, is an essential property for dyes which are used in the HTP process. The presence of cationic or anionic groups inhibits sublimation and, therefore, only nonionic dyes such as disperse dyes are capable of vaporising, and hence are suitable for HTP.

The disperse dyes most extensively used in transfer printing are those of the diazo and anthraquinone type. Studies carried out on the former, 181 •821 and latter,1831 show that the tendency of a dye to sublime decreases with an increase in molecular weight, molecular volume, and the presence of polar groups. It has been stated that the most suitable dyestuffs for transfer printing are those with a molecular weight of between 240-340, 1751 and it is important to work with groups of dyes having similar sublimation characteristics.

The number of polarisable groups (e.g. -N02, -CN, -S02R, -NH2, and -NHR) should not be excessive since the tendency to sublime decreases with an increase in polarity. Ionised groups such as sulphonic acid residues, should be absent. 1601

There are two structural features that appear to contribute to the volatility of the disperse dyes in addition to a relatively low molecular weight. The presence of bulky substituent groups, as in Figure 2.3 ., 1601 can prevent close molecular packing and strong intermolecular bonding from occurring in the dye solid. This will result in a relative decrease in sublimation energy in spite of a higher molecular weight, and hence confer good transferability. Secondly, the presence of polarisable groups capable of hydrogen bonding is acceptable only where the resultant H-bond is intramolecular in nature. 1601 (see Figure 2.4.)

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There are a number of specific properties which are desirable for disperse dyes employed in the HTP process. These properties include:

(i) excellent colour yield, (ii) excellent heat transfer dyeing properties (transferability), (iii) excellent colour fastness other than sublimation, and, (iv) excellent printing ink suitability. 1841

The selection of suitable dyes is limited by certain constraints placed upon it by factors which are inherent in the process. 185•861 The dyes must:

(i) Sublime at a rate suitable for the fabric. (ii) Sublime in a temperature range which is low enough to prevent melting or discoloration of the fibres (150-220°C). (iii) Have little or no substantivity for the cellulose-based papers used as the support but be readily absorbed by the synthetic­ polymer fibres to give adequate depth and sufficient colour fastness to light, washing, etc., for the intended end-use of the fabric. (iv) Sublime in mixtures with other dyes with similar rates of vaporisation. 1771

The uptake of a particular dye varies enormously with the type of fibre. 187•881 So, the problem consists of finding a range of dyes with similar vaporisation rates suitable for a particular type of synthetic-polymer fibre or blend. Also, they must be dyes which do not change their physical form or undergo chemical reaction during sublimation with deterioration of transfer

properties. 189•901

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,,-----a T b R A C N s F E R ------d

170 180 190 200 210 220 Degrees Celcius Figure 2.5. Effect of Temperature on Transfer

,,., ,,.,b T ----=-;r---a R A N s F E R

0 10 20 30 40 50 60 Time (seconds) Figure 2.6. Effect of Time on Transfer

D E p T H

of s H A D E 3 6 9 12 15 18 kilopascals (kPa)

Figure 2.7. Effect of Pressure on Transfer Chapter Two Quick-Response Methods

2.3.3. Process Variables

Three items, namely temperature, time and pressure, can be listed as variable conditions in conducting heat-transfer printing. The type of substrate will largely determine the time and temperature of the dye transfer. For instance, under identical transfer conditions, the same dye on paper may not give the same depth of shade on different fibres, or on the same fibre type in different physical forms or weaves.

Figures 2.5., 2.6., and 2.7. graphically illustrate the effects of temperature, time and pressure on dye transfer.

Effect of Temperature: Sample (a) represents a dye which is highly sublimable; samples (b) and (c) represent the region of acceptability and sample ( d) possesses a vaporisation characteristic which is too low. 1911 (Figure 2.5.)

Effect of Time: Curve (a) represents the behaviour of a normal dye. When this curve is plotted against the "square of the time", a straight line results - (b). 1911 (Figure 2.6.)

Effect of Pressure: The depth of shade produced rises rapidly with increasing pressure to a maximum at about 1OkPa. Any increase in pressure above this level gives no further increase in depth. 1911 (Figure 2.7.)

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20 Seconds Exposure y 60 E L L 0 50 w N E s 40 s

I 30 N D E X 20

10 Nylon 6.6

Polyester 0 1------~ 170 180 190 200 210

Temperature in Degrees Celcius

Figure 2.8. Effect of Time and Temperature on the Yellowness Index of Various Fibres Chapter Two Quick-Response Methods

Fabric Calender Machine Vacuum Machine Softening Fabric Temp.(CC)

Temp. Time Temp. Time (OC) (Sec.) (OC) (Sec.)

Secondary 190-205 185-195 10-25 185-195 8-12 Acetate

Triacetate 140-200 185-200 20-30 185-200 10-15

Nylon 6 180 185-195 10-15 185-195 5-8

Nylon 6.6 230 185-195 15-20 185-195 8-10

Acrylic 190-240 185-195 10-15 200-205 10-15

Polyester 230-240 200-230 20-40 210-220 10-20

Polyester/ Nil 200-230 20-40 200-230 10-20

Cotton

Polyester/ Nil 200-230 20-40 200-230 10-20

Wool

Table 2.1. Recommended Temperature and Time for the Heat Transfer Printing of Different Textile Fabrics Chapter Two Quick-Response Methods

It is fundamentally important to monitor the temperature and time of transfer to avoid distortion of the fabric properties. Both a loss of fabric handle, and a distinct yellowing can occur if these two variables are left unchecked. The recommended time and temperature for the transfer printing of different fabric types are listed in Table 2.1 .,'92•931 while the effect of temperature on the yellowness index (YI) of various textiles is shown in Figure 2.8. 1941 The diffusion of dye into the fibre, and hence the dye transfer, generally increases with an increase in the transfer temperature and transfer time. The wash fastness also improves with higher temperature and/or longer transfer times. 1871

2.4. Advantages and Disadvantages of the Heat-Transfer Printing Process

When considering the HTP process as a quick-response technology, it is fundamentally important to weigh up both the advantages and disadvantages of the process. At first glance, it appears that the obvious benefits of a quick colouration technology far outweigh the costs. By outlining both the benefits and the costs, it is clear that HTP most certainly holds great promise as a quick-response technology. The advantages and disadvantages of the HTP process, as compared with conventional screen or roller printing processes, are outlined below.

2.4.1. Advantages

1. Transfer printing completely eliminates the problems of pollution.

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- Water base inks are used for the printing of the paper, and no water used in the textile printing stages of the process. l95I

- It is a dry heat process that requires no aftertreatments such as steaming, rinsing, or reduction clearing. 1751

- At no stage during the process are toxic fumes produced and, consequently, no measurable air pollution is produced. 1961

2. Transfer printing is more economically viable.

- Transfer printing requires a minimum of manufacturing space as compared with conventional printing. 1951

- The capital investment for HTP is relatively small compared with other forms of textile printing. Today, one would expect to pay 10 times more to set up a roller or screen printing system than an HTP process. 1971

- There is no need for high-cost, skilled artisans to run a transfer calender; 1971 semi-skilled labour can be rapidly trained to use the machine. 1751

- Heat transfer printing requires a small fraction of the labour needed for direct printing. 1951

- The HTP process offers significant savings in the cost of energy, as it only requires a fraction of the energy that is needed for conventional wet printing. 1951

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- A considerable saving occurs by eliminating faulty printing at the paper stage. Faulty prints on fabric are usually sold for a fraction of the price that they would normally command.

- Fabric wastage from transfer printing is usually less than 1%. In comparison, it has been traditional for wet printers to allow between 5-12% wastage for shrinkage and seconds. 1951

3. Transfer printing has many technological advantages.

- With transfer printing, there is virtually no downtime when changing a colour scheme or a pattern. 1751 The changeover at the transfer calender from one design to the next is almost immediate. The new pattern is taped on to the old transfer paper which is then cut off. This can be done without slowing down or stopping the machine. Design or colour change has even been automated to the point where patterns can be changed at the push of a button. This makes the transfer cost difference between small and large runs very small. 1951

- Paper is simply easier to print than fabric. It does not stretch or bow and permits perfect registration possibilities with any number of colours. Paper further allows for endless design capabilities. It is also relatively cheap and thereby drastically reduces the cost of seconds. 1951

- A wide range of synthetic materials can be printed. 1751

- Problems associated with colour matching are eliminated. 1751

- Stock-holding costs are lower since the cost of storing printed fabric is 2-5 times that of storing an equal quantity of printed paper. 1851 In

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addition, standard fabric qualities, e.g. woven and knitted suitings, can be warehoused and printed as required, facilitating a quick­ response to changing fashion needs. 1771

- The process can be carried out m a continuous manner or with individual garments. 1751

2.4.2. Disadvantages

To be fair and honest, transfer printing also has its drawbacks. It is not completely suitable for short runs, which are common for wool. The need to produce long lengths of transfer paper leads to loss of exclusivity in design. Exclusivity is an important feature of printing on wool.

The paper itself

The production of transfer paper is costly, and only long printing runs offset the set-up costs. As beautiful as it is as a printing substrate, paper is also a non-reusable raw material. After it has served its purpose, the used paper is either thrown away or sold cheaply as gift wrapping. Unfortunately, the paper can not be reused or recycled. 1951

The transfer step

This is an additional stage which is not present in the direct printing process. New calenders have made transferring faster and cheaper, but it is still there. This last step, plus the paper costs, places an economic lower limit as to what transfer printing can do. 1951

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Paper

.____D_y_e_C_ry_s_ta_I_ __.I · ·

1' I [1] I I 1SubUmatfon I j '+' Diffusion in Dye Vapour .______._ I : : ::: ' Gas 1' I I [2] I Condensation I I 'V

Fibre Surface 1- ...•

1' I I Diffusion in [3] I I Polymer I '¥

Fibre Interior

Figure 2.9. Dye Transfer Mechanism in Heat-Transfer Printing Chapter Two Quick-Response Methods

The dyes used

Only disperse dyes with good sublimation properties are suitable for the process. Consequently, only those textiles such as polyester, cellulose diacetate, cellulose triacetate etc., which have an affinity for this class of dyestuff, can be transfer printed. Natural fibres such as cotton, wool etc., which have low affinity for the disperse dyes, can not be transfer printed successfully. 1601

The fabric properties

Due to high pressures and elevated temperatures, in some cases, there is distortion of the fabric construction and a loss of certain fibre properties. I75I

2.5. Basic Operation of Heat-Transfer Printing

There are three main stages in the HTP process. Figure 2.9. 1981 gives a diagrammatic representation of these stages.

1. Initially, when heat is applied to the reverse side of the transfer paper, the disperse dyes sublime. This vaporised form of the dye molecules is then situated in the air gap between the transfer paper and the substrate. This air gap exists simply because it is impossible to deform the transfer paper to give a perfect contact between the fibres of the fabric surface. This air gap varies in size depending on the mechanical pressure applied, the filament diameter and/or the construction of the fabric. 1991

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2. Secondly, the dye molecules in the air gap then condenses onto the surface of the fibre. This condensation begins to occur when the dye vapour atmosphere above the paper reaches supersaturation. Also, as soon as the fibre temperature approaches the applied temperature, there is an immediate absorption of the dye vapour at, or just beneath the surface. 1991

3. Finally, the dye which is situated on the surface of the fibre then diffuses into the fibre. This is a slow process, and is the rate determining step. The rate at which the dye molecules diffuse through the polymer chains increases greatly with increasing temperature. 1981 This is because at the higher temperatures, greater segmental chain motion within the polymer occurs which results in a greater free volume.

The process continues until an equilibrium is established between dye molecules in the fabric, air gap and ink, all of which, at this time, are at the same temperature. 11001

2.6. Application of Heat-Transfer Printing to Wool

Only a very small percentage of all the wool that is processed is printed. A recent survey has shown this figure to be about 1.5% of the total world Merino wool production each year. 11011 Due to the many advantages of the HTP process mentioned earlier, it makes good sense to consider how this technology could be applied to the printing of wool. A considerable effort

-42- Chapter Two Quick-Response Methods has been devoted to the adaptation of this technique to wool, with both the International Wool Secretariat (IWS) in the United Kingdom and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia being particularly active in this field. However, due to the chemical properties of the wool, a number of problems have arisen which have made the application of HTP onto wool quite difficult.

There are two major problems associated with the application of this process to wool. Firstly, the anionic dyes that are generally used for the dyeing and printing of wool are not sublimable, and thus are not suitable for the HTP process. Therefore, these dyes can not be substituted for disperse dyes in heat-transfer printing, because the dyes employed in this process should have the ability to sublime within the temperature range 180 - 240°C.

Secondly, untreated wool has low affinity for the disperse dyes used in HTP. Due to this lack of affinity, there is very little transfer of the dye from the paper to the fabric. The transferred dyestuff is not fixed and is readily washed out during the first washing process. Accordingly, during the HTP of polyester/wool blend fabrics, the polyester fibre part is effectively printed but the wool fibre part remains essentially undyed. This results in very light or thin colour as a whole, and as a result, a solid shade can not be obtained. Therefore, for this technique to be employed in the printing of wool, it is necessary to increase the affinity between the wool fibre and the disperse dyes. An added bonus as a result of this increased affinity between the wool fibre and the disperse dyes is the prospect of being able to dye wool blends in the one dye bath. This would result in a considerable saving of time, money and resources.

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2.7. Increasing Wool's Affinity for Disperse Dyes

For a number of years now, there has been a considerable interest in the pretreatment of fabric in an attempt to alter the chemical properties of the wool, so as to utilise the HTP process. This has primarily resulted in efforts to increase the affinity of the wool fibre for conventional disperse dyes. The basic principle is similar to that of the Shikbo Mermaid Uni. process, 1102•1031 that is, an increased hydrophobic character of wool should impart an increased disperse dye affinity for wool and, as a result, should make wool suitable for disperse dyeing or HTP.

Several methods for increasing this affinity have been proposed. Some of the pretreatments that have been studied include:

- Pre-impregnation with high concentrations (20% o.w.f.) of simple polar organic compounds such as urea, thiodiglycol, or lactic acid. 11041

- Pre-impregnation with anionic surfactants at moderate levels (2-6% o.w.f.). 11051 This method has subsequently been developed as the CSIRO-IWS Keratrans process usmg

specially developed metallizable disperse dyes. 1106•1071

- Benzoylation of wool. 11081 This process has similarities with the Shikbo Mermaid Uni. process and allows the subsequent successful employment of disperse dye printed papers.

- Modification of Wool with Hydrophobic Compounds containing the (di) Chloro - s - Triazinyl Reactive Group. 11091

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Research has shown11101 that the s-triazinyl reactive dyes produced unlevel wool modification. Consequently, poor disperse dyeing and HTP resulted. However, more recent work11111 has shown that other reactive hydrophobes are more suitable for increasing wool's affinity for disperse dyes.

Although some disadvantages are evident in the above-mentioned processes for increasing wool's affinity for disperse dyes, they have supported the proposition that an increased hydrophobic character of wool should impart an increased disperse dye affinity for wool and, as a result, should make wool suitable for disperse dyeing or HTP. This new concept showed much promise and will hopefully lead to a transfer printing process for wool and wool-blend fabrics employing conventional disperse dye transfer printing paper. 11121

2.8. Reactive Hydrophobes

Wool is a nonhomogeneous polymer, because the chemical structures of the side-chains in the repeating units of the wool fibre are different. As a result, some regions of the wool fibre may show hydrophobic character, while others may show hydrophilic character. Hydrophobic regions are formed by hydrocarbon groups. Hydrophilic regions of the wool fibre are formed by groups having inorganity.

In natural wool, there are so many hydrophilic regions and their affinity for disperse dyes is low. Consequently, the affinity of disperse dyes for the hydrophobic regions of wool is greatly reduced by the high proportion of hydrophilic regions in wool.

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To be able to disperse dye wool, either the hydrophobic character of wool must be increased or its hydrophilic character must be diminished. One such method involves the blocking of the hydrophilic groups and increasing the proportion of hydrophobic regions by modification of natural wool. However, the chemical modification should be carefully controlled so as to keep wool's other properties intact, and of course, this alteration should be permanent.

The following points were considered in the design of the modifier. 11131

(1) The modification should be confined to hydrophilic side­ chains as far as is possible and both the amide bonds in the main chains and the disulphide side-chains should be kept intact.

(2) The modifier should be able to react and form covalent bonds with most hydrophilic side-chains in wool.

(3) The modifier should be colourless and should have a relatively high proportion of hydrophobic groups.

Reactive hydrophobes are modifiers which are used to increase the hydrophobic character of wool. Their structure is similar to that of reactive dyes, however, the basic difference is that instead of a chromophore being linked to the reactive system as in the case of reactive dyes, a hydrophobic group is linked to the reactive system. Their basic structures can be represented by the following formulas.

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D--B--R L--B--R

Reactive Dye Reactive Hydrophobe

Where, R = Reactive System B = Bridging Group D = Chromophore L = Hydrophobic Group

2.8.1. Reactive System

Any reactive group which is capable of combining with inert and colourless hydrophobic group(s) via a bridge, is a potential reactive system for reactive hydrophobes. The desirable reactive systems incorporated in the reactive dyes for wool exhaust dyeing should satisfy the following criteria. 11141

1. The synthesis of corresponding reactive hydrophobes should be easy and economical.

2. It should possess significant resistance to hydrolysis both during storage as a dry powder and during application to wool in weakly acid dyebaths.

3. The reactive system should have high reactivity so that a sufficient degree of modification can be achieved. Also, its reactivity should ensure maximum wet fastness.

4. The dye-fibre covalent bonds should be sufficiently stable after they are formed.

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5. Since our primary aim is to render wool hydrophobic, the reactive system selected should possess minimum hydrophilic character.

2.8.2. Hydrophobic System

The desirable hydrophobic systems incorporated in the reactive dyes for wool exhaust dyeing should satisfy the following criteria. 11151

1. It should be colourless.

2. It should have sufficient hydrophobic character.

3. It should be inert, i.e. it should be devoid of any water solubilising groups, polar groups and any reactive groups (other than what is necessary for linking with the reactive system).

2.9. The Inorganity-Organity Ratio

As mentioned earlier, the hydrophilic regions of the wool fibre are formed by groups having inorganity. The contributions of different groups to wool's hydrophilic character can be assessed by the Inorganity-Organity Ratio (IOR) method. Professor Fujita of Kumamoto University proposed the concept of the ratio of inorganicity to organicity of organic compounds. 11161 He identified that every organic compound has inorganitic and/or organitic character. Therefore, IOR is defined as the ratio of the inorganitic value to organitic value for a given organic compound. The ratio is easily determined with the use of the following formula:

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IOR Inorganitic Value Organitic Value

Where,

Organity :::::} Is mainly controlled by the part capable of reducing the action of the substituting group. In some cases, the contribution may come from substituting groups having both organity and inorganity. It corresponds to the hydrophobicity of an organic compound.

Inorganity :::::} Is controlled by an opposite part, i.e. substituting group and abnormal part having static character. It corresponds to the hydrophilicity of an organic compound.

Note: Substituting groups refer to the groups stemming from inorganic compounds, such as H20, H2C03, NH3, and H2S04. The formation of common organic compounds can be regarded as the combination of methylene with inorganic compounds.

The IOR method assigns 20 to each carbon atom representing elementary hydrocarbon, (-CH2-). So, the organity of a compound can be expressed by the multiplication of 20 and the number of carbon atoms. The IOR method assigns 100 to hydroxyl in correspondence with the organitic value of a carbon atom. The value of other substituting groups and abnormal parts are then decided on the basis of the values of methylene and hydroxyl groups. Some of these are listed in Appendix 2.1.

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= Photons

CD = Oxygen (02) C. = Radicals

ELECTRODE

d3 +-- ,-~

~- tb (D___ _

iR Wool

Treater Roller Dielectric

- +-- Common Ground

Figure 2.10. Reactions in a Corona Discharge Chapter Two Quick-Response Methods

2.10. Plasma Treatment

The physics definition of a "plasma" is an ionized gas with an essentially equal density of positive and negative charges.'1 171 The most suitable way to generate a plasma is through an electrical discharge, and this effect can be achieved either under atmospheric conditions, in which case it is termed Corona Discharge (CD), or under a vacuum, when it is termed Glow Discharge (GD). Both types of discharge are described as Low Temperature Plasma (L TP), although in practice, the temperature may vary from room temperature to 300°C.'1 181

It has been known for at least sixty years that a plasma could produce desirable changes in the surface properties of materials. As far as wool is concerned, plasma treatment reduces its tendency to felt and shrink, improves its printability and accelerates its dyeability. Before focusing on these advantages, it is important to consider the various forms of electrical discharge which can be used to achieve these effects.

2.10.1. Corona Discharge

A weak-current discharge under atmospheric conditions, is described as a corona discharge. 11191 The CD technique operates by generating a high frequency electric spark discharge. In general, a corona treater consists of a generator, an electrode, a treater roller and a dielectric between the electrode

and treater roller, as indicated by Figure 2.10.'1 18' 1201 The generator is necessary, in order to produce an alternating current at a frequency of between 20-40kHz and an output of 12-20kV. It is this potential that

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enables a corona to be established between the electrodes. 11201 The electrons produced at the electrode are accelerated by a high voltage in the direction of the dielectric which is situated immediately below the substrate being treated, e.g. a wool fabric. On their way to the substrate, the electrons collide repeatedly with air molecules, leading to the production of ozone and oxides of nitrogen. 11181

Due to their high energy (approximately 5eV), those electrons which reach the substrate are able to transfer their energy to covalent linkages such as C­ O (3.6eV), C-C (3.7eV), and C-H (4.3eV). In doing so, radicals are created on the fibre surface which react with ozone or nitric oxides, i.e. the fibre surface is being oxidised and thereby becomes more polar. This increase in both the surface energy and polarisation, is responsible for the increased wettability, accelerated dyeability and improved printability of wool.

2.10.2. Glow Discharge

Glow discharge plasma generation is carried out under a vacuum of 0.1-0.2 Torr with the actual discharge being promoted by the use of a capacitively coupled flow system and power source, typically operating at a frequency of 13.5 MHz. The signal from the oscillator is amplified and coupled to the discharge area either by a capacitor plate or an inductor coil. 11181 The electrons produced in a GD are of higher energy than those in a CD, as they are not slowed down by collisions with air molecules. Thus, GD electrons can better penetrate the surface of the fibre.

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Consequently, in the plasma treatment of materials, all significant reactions are generated by high energy electrons without excessive heating. Free electrons receive energy from the radiofrequency (RF) electric field and through collisions with neutral gas molecules, generate new chemically­ active species of atoms, ions and free radicals. In contrast to thermally­ induced reactions, where energy is usually equally distributed among all particles in the system, energy in plasma reactions is supplied principally to the free electrons. 11211

2.11. Effects of Plasma Treatments on Surfaces

Four major effects of plasma on surfaces are normally observed. Each is always present to some degree; however, one effect may be favoured over another depending on substrate chemistry, reactor design, gas chemistry, and processing conditions. Liston11171 divided these four effects into the following categories:

i) cleaning of organic contamination from the surfaces,

ii) material removal by ablation (micro-etching) to increase surface area, iii) crosslinking or branching to strengthen the surface cohesively, and, iv) surface chemistry modification.

-52- Chapter Two Quick-Response Methods i) Cleaning: - Cleaning of surfaces is one of the major reasons for improved bonding to plasma treated surfaces. Most other types of cleaning procedures leave a layer of organic contamination that interferes with adhesion processes. Plasma is capable of removing molecular layers from polymers and all organic contamination from inorganic surfaces. This results in hyperclean inorganic surfaces and polymer surfaces that are really the polymer and not the surface of some contamination on the polymer. Therefore, these surfaces give very reproducible bonds and, in many cases, make stronger bonds than normally "cleaned" surfaces. 11171 ii) Ablation: - Ablation is important for the cleaning of badly contaminated surfaces, for removal of weak boundary layers formed during the fabrication of a part, and for the treatment of filled or semicrystalline materials. Amorphous polymer is removed many times faster than either crystalline polymer or inorganic material. Consequently, a surface topography can be generated with the amorphous zone appearing as valleys. 11221 This change in surface can improve mechanical bonding as well as increase the area available for chemical interactionsY 171 iii) Crosslinking: - Crosslinking occurs in polymer surfaces exposed to plasmas which are effective at creating free radicals in the polymer. The electronically excited atoms and the vacuum ultraviolet light attack the polymer surface and break C-C and C-H bonds, leaving radicals in the surface. 11231 Once free radicals are created in the surface they may react with species which are present at the surface. Another effect may be to improve the heat resistance and cohesive strength of the surface, and it may also act as a barrier layer, hindering diffusion across the interfaceY 171

-53- Chapter Two Quick-Response Methods iv) Surface Chemistry Modification: - The most dramatic and widely-used effect of plasma is the surface modification of polymers, where the surface layer of a polymer is altered to create chemical groups capable of interacting with an adhesive. The inherently low surface-energy of untreated polymers hinders the wetting and interaction with adhesive systems. Typically, plasma is used to add polar functional groups which dramatically increase the surface energy of polymers.'1 171

2.12. Effects of Plasma Treatments on the Properties of Wool

The primary physical and chemical effects of the oxidative plasma treatment on wool fibres include a conversion of the fibre surface from hydrophobic to hydrophilic1124'1251 , an increase in fibre cohesion11261 , and the production of shrink-resistance. 1124•125•1271 These effects are consistent with those obtained by using conventional oxidising agents such as chlorine or potassium permonosulphate11281 and one might therefore expect the chemical reactions occurring in the presence of an oxidative plasma to be similar. 11181

Scanning electron micrographs have been used extensively to examine the physical attributes of the plasma treated wool fibre, and have conclusively revealed that macroscopic degradation is minimal. This is not at all surprising as it is consistent with the surface-specific nature of the treatment.

The chemical effects of plasma treatment are dependent on the gas or vapour introduced during the treatment process. Whereas tetrafluoroethane will result in the incorporation of difluoromethylene groups into the surface of the fibre11291 , the use of an oxidative plasma will produce both oxidised

-54- Chapter Two Quick-Response Methods carbon species and sulphonic acid residues, both of which are consistent with the production of shrink-resistance and a hydrophilic surface more suitable for printing. 11181

A significant alteration which is also apparent is the change in inter-fibre friction 11301 for plasma treated wool. The treatment produces an increase in fibre cohesion and has been used to improve the spinning performance of plasma treated top and to produce significant improvements in yarn properties such as extensibility and strength.

In addition to the marked effects on the frictional properties of the fibre and the increase in wettability, it is also possible to achieve a degree of shrink.­ resistance. This effect, which is well documented1128•131-1331 , is of particular significance since it is achieved without the chemical damage which is traditionally associated with chemical oxidative treatments.

Bradley et al. 11341 , through the use of an oxygen plasma, discovered that plasma treatment produced a significant increase in the carbon-oxygen functionality of the surface of wool. They further stated that the levels of surface oxygen achieved using the plasma technique were similar to those from wet processes. Thus, the surface of plasma treated fabrics, in this case, becomes anionic. The anionic character is believed to be due to the production of sulphonic acid and carboxylic acid groups in the epicuticle of the wool. 11351 This finding is also supported by other researchers who found that various electric discharge treatments improve dyeing. 1124•126•1361 Notable improvements in the dyeing behaviour of plasma treated wool have also been reported by Thomas et a/.. 11371 They found that dyestuff absorption by the plasma treated material is more rapid than for material which has not been pretreated.

-55- Chapter Two Quick-Response Methods

2.13. Commercial Benefits of Plasma Treatment in Textiles

The widespread introduction of legislation governing the discharge of AOX­ containing effluent is likely to cause the eventual demise of chlorination as a basis for either the shrink-proofing of wool or preparation of fabrics for printing. Consequently, there is now considerable interest in the potential of environmentally acceptable alternatives. Additional criteria, and ones which will progressively assume more significance, are the high water and energy costs associated with such traditional techniques, and this has prompted the examination of a number of dry gaseous systems including ozone, laser and plasma.

Of these, the most widely documented is the plasma treatment, and considerable progress has recently been made in terms of adapting this technology for full scale industrial production. Preliminary results from a number of sources strongly suggest that the commercial potential of such technologies will be realised, although a cost advantage over conventional techniques has yet to be demonstrated. 11181

Goto et al. 11381 have stated that the plasma method has very interesting advantages as follows:

a) Dry process; no environmental pollution, energy and water savmgs.

b) As the reaction of textiles with low temperature plasma takes place only on the very thin outer layer of the fibre, there is no effect on the bulk properties of both fibre and fabrics.

-56- Chapter Two Quick-Response Methods

c) As the energy level of the gas in low temperature plasma is so high, a variety of reactions such as etching, incorporation, crosslinkage (or chain breakage), plasma polymerisation etc. can be applied to textiles.

Based on these advantages, many researchers have examined the suitability of the low temperature plasma method for the modification of natural

fibres. !139-1411 Goto et al. 11381 , for example, have used the plasma method for the scouring of greige cotton fabric.

Most relevant to this project is the potential commercial benefit obtained from a greater dyeing efficiency. Research1124•126•1361 has shown that plasma treated wool samples require a shorter dyeing time compared to untreated wool samples. When both a treated sample and an untreated sample are dyed in competition with each other, the treated sample adopts a much greater depth of colour, irrespective of the dye class selected. The obvious advantages include: greater productivity, reduced costs per batch, and quicker customer response.

The observations outlined above in respect to dyeing advantages are indeed conducive to the development of a quick-response colouration technology. The different degrees of dye uptake by the treated and untreated wool samples also opens up possibilities of late-stage colouration effects. The combination of these two observations has resulted in research which utilises a plasma treatment to achieve a quick-response late-stage colouration effect. The main focus of the work was to determine which class of dye produced the most significant colouration effect. It is therefore appropriate at this stage to give a brief outline of the relevant dye classes and their attributes.

-57- Chapter Two Quick-Response Methods

Levelling Acid

Moderately Acid

Milling Acid

Super Milling Acid

Mordant Chrome Dyes Metachrome Wool Dyeing Afterchrome

Metal-< 1: 1 Premetallised Complex Dyes 2: 1 Premetallised

Mono/unctional Reactive< Dyes Multifunctional (X - Linking)

Figure 2.11. Classification of Wool Dyes Chapter Two Quick-Response Methods

2.14. Dyes for Wool

To be able to deal with the large number of dyes that are available for dyeing wool, it is best to classify them. For the purposes of this thesis, four broad classifications have been used, each with its own sub-classes. Figure 2.11. diagrammatically represents these categories. It is the role of the following section to describe the dyes in each class, and to detail the mechanisms of dye fibre interaction for each type of dye.

2.14.1. Acid Dyes

Acid dyes are the most economical and therefore by far the most popular dyes amongst those used to colour wool. 11421 They are so called because they are applied to wool from dyebaths in acidic or neutral (~pH 8.5) conditions. Acid dyes are usually of low to moderate molecular weight (300-600), and usually feature one or more sulphonic acid, or sodium salt of sulphonic acid groups. The number of these groups within a dye molecule is the "degree of sulphonation". The number of sulphonic acid salt groups and the hydrophobic/hydrophilic balance in combination largely determine the dye's solubility in water and it's affinity towards wool. Acid dyes are usually mono or disulphonated and can be classified into four groups. 1142•1431 i) Levelling Acid Dyes: Even within this one group, there are two main subdivisions: monosulphonated and disulphonated. They both have very good levelling and migration properties, however, their wet fastness is no better than moderate, and in some cases it is poor. The monosulphonated dyes have a relative molecular mass (r.m.m.) in the 300-500 range, migrate

-58- Chapter Two Quick-Response Methods well, and give good coverage of dyeability differences within the fibre. Their wet fastness is slightly higher than that of the disulphonated dyes. 11441

Disulphonated dyes have somewhat higher r.m.m. values (400-600) but do not cover dyeability differences quite so well as the monosulphonates do. Since the general trend with acid dyes is for migration to fall and wet fastness to increase as r.m.m. rises, it can be concluded that the additional sulphonate group in these dyes is responsible for the difference in properties from the monosulphonated dyes, despite their slightly higher r.m.m. 11441 ii) Moderately Acid Dyes: These dyes are sometimes referred to as "Half­ Milling" dyes, or "Perspiration-Fast" dyes. They are generally monosulph­ onated molecules with molecular weight in the range 500-600. These dyes are applied from liquors of pH 3.5-4.5 with the aid of sodium sulphate. They exhibit superior wet fastness properties to levelling acid dyes, but retain some of the migration properties. 11441 iii) Milling Acid Dyes: These are typically disulphonated molecules with high molecular weight. (In the range 600-900). Therefore, they have a much higher affinity to the wool fibre than their affinity towards aqueous solution. Compared to the other dyes already described, the pH of application is higher. (Approx. 4.5-5.5) This increase in pH results in a slower dye diffusion and migration through the fibre which, in turn, improves the levelness. iv) Super Milling Acid Dyes: These dyes are similar in molecular weight and degree of sulphonation to milling dyes. Their superior fastness properties are a consequence of the presence of alkyl groups within the

-59- Chapter Two Quick-Response Methods

Concentration of Hydrogen, Chloride & Dye Dye ions Ions in Bath Hydrogen ions

Time

Figure 2.13. Representation of the Rate of Adsorption of Ions by Wool from an Acid Dyebath Chapter Two Quick-Response Methods

~ Normal wool before dyeing.

Acid is always added to the wool first.

The acid frees up the NH3 + by titrating the COO-.

The counter ion from the acid diffuses into the wool.

( 10 minute period to allow even acid penetration and adsorption).

Dye is then added (anion).

~ Chloride is released.

Figure 2.12. Ion Exchange During the Dyeing of Wool with Acid Dyes Chapter Two Quick-Response Methods molecule, which render the dye hydrophobic. Level results are harder to achieve using these dyes, and a pH in the range of 6.0-8.5 must be used to apply them. 1:2 Metal Complex or "Pre-metallised" dyes fall under the super milling acid dye category also. These dyes are usually chromium chelates with either one or two sulphonyl groups to increase solubility and fibre affinity. 1: 1 pre-metallised dyes are also in existence, but their use is limited because they require extremely low pH of application, causing unacceptable levels of fibre degradation.

Acid dyes are only applied to wool and polyamide fibres because they both contain internal sites that can accept a positive charge in acid solutions. Both of these fibres have -NH2 groups which, in the presence of Ir (acid), can become -NH/. Therefore, they can be dyed successfully by acid dyes from an acidic dyebath. Without the presence of acid, the dye will not be attracted as strongly to the wool. Figure 2.12. gives a schematic representation of the ion exchange that occurs when the acid dye is added to the wool.

Put simply, the dye molecule is hydrophobic in character, and hence prefers to be on the fibre, whereas er likes H20 better. When wool is immersed in the dyebath, it would be expected that the smallest and most rapidly diffusing ions would be quickly adsorbed while the larger and more slowly diffusing dye anions would follow more slowly.

Figure 2.13. gives a simplistic representation of the rate of adsorption of ions by wool from an acid dye bath.'1 451 The diagram shows that initially, there is very rapid adsorption of hydrogen ions and chloride anions. As time proceeds, the more slowly diffusing dye anions displace the chloride ions

-60- Chapter Two Quick-Response Methods from the wool, as demonstrated by the increase in the concentration of chloride ions in the bath.

In order to slow down the rate at which the negatively charged dye molecules are attracted to the positive dye sites on the wool, other negatively charged molecules are added to the dyebath solution. These negative ions (usually sol- from Glaubers salt - Na2S04) are small and therefore highly mobile. They reach the positive dye sites on the fibre before the slower moving, larger dye molecules. Since now there are fewer positive charges on the fibre, adsorption of the dye is slowed down. With slower adsorption, there is more time for the dye molecules to be evenly distributed throughout the fibre. The large, slow-moving dye molecule can displace a small sulphate ion from the salt away from the dye site, but is less easily dislodged in turn because of its hydrophobic nature.

After the dye molecule has been adsorbed, it is held in place with Van der Waals bonds as well as by ionic attractions. Therefore, it will not be dislodged by other molecules. The charge on the dye molecule has been canceled by its adsorption to the opposite charged site on the fibre. This cancellation of charge is very important for holding acid dyes inside the fibre.

2.14.2. Chrome Dyes

Chrome dyes are essentially acid dyes and they are applied in a similar way. They exhibit very good level-dyeing and migration properties and, following chroming, excellent wet fastness. The main difference between chrome dyes

-61- Chapter Two Quick-Response Methods

Oxidation of Cr (VI) ----- Cr (IV) Cystine

Oxidation of Cr (IV) ----- Cr (II) Cystine & Tyrosine

Wool-COOH Cr (II) ----- Wool-COO.Cr (II)

Air Wool - COO.Cr (II) ----- Wool - COO.Cr (III) Oxidation

2 (Dye) Wool - COO.Cr (III) --- Wool - COOH + Dye.Cr (111).Dye

For Example: J

Solochrome Navy 2R

Figure 2.14. Reactions During Afterchrome Dyeing of Wool Chapter Two Quick-Response Methods and acid dyes is that the former have molecular structures that enable them to form chelates with chromium (III) ions. 11461 Towards the completion of the dyeing cycle, appropriate levels of potassium dichromate are added. Figure 2.14. depicts the reactions that are taking place in a chrome dyeing. Firstly, the chromium is reduced from Cr(VI) - (dichromate) - to Cr(III) in a multi-step process, with some of the steps involving interactions with the fibre. 11471 The end result is a chromium (III) - dye chelate which is more than twice the size and molecular weight of the original dye.

Figure 2.11. shows a further classification of chrome dyes into one of three groups, based primarily on their method of application. These groups are mordant, metachrome and afterchrome. i) The chrome mordant method: This method involves the prechroming of the wool prior to the application of dye. This technique results in a good coverage of wools of different dye affinity and permits simple shade matching. However, a disadvantage of the chrome mordant process is that it requires two separate baths, and is consequently expensive on time, energy and water. ii) The metachrome method: This method involves the simultaneous application of both the dye and the chromium into the dyebath at neutral pH (6.0-7.0). This restricts the method to those dyes which have reasonable neutral affinity for wool. Within the neutral pH range, both iron and copper contaminants in the water are insoluble, resulting in little interference with the chroming. (Most mordant dyes are polychromatic, that is, they give different colours when complexed with different metals.) Complex formation between the dye and a mordant other than chromium would lead to a different dyed shade and also different fastness properties. 11441

-62- Chapter Two Quick-Response Methods

The disadvantages of simultaneous dyeing and chroming are:

- The limited number of suitable dyes. - The inability to achieve very heavy shades, because of limited exhaustion at neutral pH values. - High residual levels of chromium, resulting from less than optimum dye bath exhaustion of the mordant at neutral pH. iii) The afterchrome method: This method is now the most widely adopted technique for the application of chrome dyes. The dyeing and chroming processes, although separate steps, are often carried out in the same bath, thereby reducing dyeing times, water and energy requirements. With this method, the dye is fully exhausted into the wool fibres before the addition of dichromate. Afterchrome dyeing gives better fastness properties than either of the other two chrome dyeing techniques, and there is no restriction on shade. The main disadvantage of afterchrome dyeing is the difficulty in shade matching, since the final colour is not developed until the chroming stage. 11441

The afterchrome method has now become the sole technique for applying chrome dyes, as it offers better levelling, greater fastness, as well as lower levels of chromium in effluents. The other two methods are outlined only for historical interest. Chromium dyes are cheap to use and display extremely high wet fastness. Therefore, they are still very popular, particularly for heavy shades such as blacks, dark browns and navy blues. However, their popularity is slowly diminishing due to the high level of oxidative degradation of the wool fibre caused by their method of application, and the tightening of environmental laws regarding disposal of chromium-containing waste waters.

-63- Chapter Two Quick-Response Methods

2.14.3. Metal-Complex Dyes

In metal-complex dyes one metal atom, commonly chromium, is complexed with either one (1:1 metal-complex dye) or two (2:1 metal-complex dye) molecules of a typically monoazo dye that contains groups (such as hydroxyl, carboxyl, or amino groups) that are capable of coordinating with the metal. Generally, the shades that are achieved by metal-complex dyes on wool are duller than those given by non-metallised acid dyes, but slightly brighter than those obtained using mordant dyes. 11481 i) 1:1 Premetallised Dyes: These dyes exhibit excellent level-dyeing and penetration characteristics and are especially suitable for dyeing unneutralised carbonised and acid-milled wool. They have the ability to cover irregularities in the substrate and produce dyeings on untreated wool of good to very good light fastness and moderate to good fastness to wet treatments, even in deep shades.

Strongly acidic dyebaths are commonly used to apply 1: 1 premetallised dyes (pH approximately 2). Under these conditions, the dyes possess excellent migrating and thus levelling characteristics. Because prolonged boiling under such low pH conditions can cause fibre damage, either reduced amounts of sulphuric acid or other acids such as formic acid or a proprietary levelling agent can be used. The dyes can also be applied at 80°C so as to reduce fibre damage.

Maximum exhaustion of the dyes is achieved in the pH range 3 to 5, depending on the dye, but these conditions give rise to tippy dyeings of poor wet fastness. Under such pH conditions, the dye will interact with the fibre by virtue of:

-64- Chapter Two Quick-Response Methods

Figure 2.15. Chemical Structure of C.I. Acid Violet 78

-

-

Figure 2.16. Chemical Structure of C.I. Acid Orange 148 Chapter Two Quick-Response Methods

a) ion - ion (electrostatic) forces operating between the anionic dye and protonated amino (-NH/) groups in the fibre,

b) coordination of the chromium ion in the dye with appropriate ligands (such as carboxyl or imino groups) in the substrate, and,

c) ion - dipole, dipole - dipole and related forces. 11481

ii) 2:1 Premetallised Dyes: These dyes are usually applied under weakly acidic or neutral pH conditions, and as a consequence, are sometimes referred to as 'neutral-dyeing' metal-complex dyes. Within this category there are a further two sub-categories namely: weakly polar and strongly polar 2: 1 metal-complex dyes.

a) Weakly polar 2:1 metal-complex dyes: This category implies that the metal-complexes are free of strongly polar, ionic

solubilising groups such as -S03H or -COOH. Weakly polar 2: 1 metal-complex dyes display very good to excellent light fastness and very good fastness to wet treatments on wool in pale to medium depths. The dyes exhibit good levelling and penetration properties and typically yield nonskittery dyeings. Levelling is dependent on the pH and temperature of application, and is enhanced by a proprietary levelling agent and the addition of Glauber' s salt. Figure 2.15. is an example of this type of dye. 11481

b) Strongly polar 2:1 metal-complex dyes: As exemplified by

Figure 2.16. 11481 , these dyes exhibit very good to excellent light fastness, and very good fastness to wet treatments on wool.

-65- Chapter Two Quick-Response Methods

Generally, they display higher fastness to wet treatments on wool than do their weakly polar counterparts. Application of the dyes is carried out in the pH range 5 to 7 although a pH of 4 may be used. The use of a proprietary levelling agent is essential to prevent skitteriness.

2.14.4. Reactive Dyes

Reactive dyes are umque among other dyes in that they are covalently bonded to the substrate. They are known and used for their excellent wet fastness properties and bright colours. However, they are notoriously expensive, and although current application methods achieve good levelness, they are avoided when colouring piece goods, where levelling is extremely important. 11421

When reactive dyes are applied to wool, they react with the functional side chains and terminal amino groups in wool. The mechanism of reaction, in which they react and form covalent bonds with wool, can be divided into two types: the nucleophilic substitution reaction and the Michael addition reaction. 1601

2.14.4.1. Nucleophilic Substitution Reactions

The reactive system which is capable of undertaking this type of reaction,

usually has a leaving group such as halogen (-X), sulpho (-SO3H) or quaternary nitrogen (-N+R1R2R3Cr). The reactive center on the carbon atom should be activated by an electron-withdrawing group adjacent to it,

-66- Chapter Two Quick-Response Methods

Figure 2.17. The Reactive Centers on 2,4-Difluoro-5- Chloropyrimidyl Amino Dyes

0 0 \II .._ ir 0+ \JI.._ 0· 0+ Dye - C-C = CH2 Dye-S- CH=CH2 +I * (II * Br 0

Figure 2.18. The Reactive Centers on a-Bromoacrylamido Dyes and Vinylsulphonyl Dyes Chapter Two Quick-Response Methods

such as sulphonyl (-S02-), carbonyl (-C=O) or a nitrogen atom in the aromatic ring, and by the leaving group attached to it. For example, the reactive group marketed in 2,4-difluoro-5-chloropyrimidyl amino dyes is displayed in Figure 2.17.

Consequently, the electron-deficient carbon atom easily attracts the free lone pair of electrons on the nucleophile and undergoes a biomolecular nucleophilic substitution reaction (SN2) as follows:'1 491

Dye - X- L + NuH- protein Dye - X- Nu - protein + HL

where NuH- = -SH, -NH2, or -OH; L = leaving group; and X = activated group.

2.14.4.2. Michael Addition Reactions

The reactive system which is capable of undertaking this type of reaction, usually has an unsaturated carbon-carbon double bond. The reactive center on the carbon-carbon double bond should be polarized by electron­ withdrawing groups adjacent to it, such as carbonyl (-C=O) or sulphonyl (-S02-). For example, the reactive group marketed in ex - bromoacrylamido dyes and vinylsulphonyl dyes formed gradually from N-methyltaurine­ ethylsulphonyl dyes during exhaustion dyeing are displayed in Figure 2.18. Consequently, the electron-deficient carbon atom easily attracts the free lone pair of electrons on the nucleophile and undergoes a 1,2 transnucleophilic addition.

-67- Chapter Two Quick-Response Methods

0 Br II I + Peptide-NH2 D-NH-C=CH2

(I) (II)

0 Br NH - Peptide 0 NH - Peptide II I I II I D - NH - C - C - CH2 D-NH-C-C = CH2

(Addition Product) (Substitution Product)

Peptide (III) I 0 N II I \ D - NH - C - C - CH2

(Aziridine Ring)

i + Peptide - NH2

Peptide (IV) I 0 NH II I D - NH - C - C - CH2 - NH - Peptide

Figure 2.19. Reaction ofLanasol Dyes with Wool Chapter Two Quick-Response Methods

Commercial Reactive Group Reaction Name: Structure: Mechanism:

Br I Michael Addition Lanasol -NH-CO-C=CH2 (Ciba Geigy) Nucleophilic Substitution ( a-bromoacrylamido)

-NH Drimalan F N~F (Sandoz) or ON Nucleophilic Substitution Verofix Cl (Bayer) F

(2-4-d i fl uor-5-ch loropyrimidy I)

CH3 I -SO2-CH2-CH2-N-CH2-CH2-SO3H

Hostalan (N-methyltaurine-ethylsulphone) Michael Addition Hostalan E or (Hoechst) -SO2-CH2-CH2-O-SO3H

(P-sulphatoethylsulphone)

Table 2.2. Reactive Dyes for Wool Chapter Two Quick-Response Methods

Dye - X - CH= CH2 + NuH- protein ----+ Dye - CH2CH2 - Nu - protein

2.14.4.3. Conventional Reactive Dyes for Wool

The main type of conventional reactive dyes include vinyl sulphone, (a­ chloro) acrylamide, w-chloroacetamide and heterocyclic (chlorotriazine or chlorofluoropyrimidine) dyes. However, only three ranges of reactive dyes, namely, a-bromoacrylamido (Lanasol), 2,4-difluoro-5-chloropyrimidyl amino (Drimalan F, Verof,x or Reactolan) and N-methyltaurinoethyl­ sulphone (Hostalan) dyes, are able to really satisfy wool dyeing requirements up to now. These can be viewed in Table 2.2. 1149•1501

Lanasol dyes have been the most successful class of reactive dyes for wool. They contain one or more a-bromoacrylamido reactive groups, and are postulated to react with the wool fibre via the reaction sequence shown in Figure 2.19. The reaction sequence depicts different stages by the use of Roman numerals. Mosimann11511 postulated the reaction up to (III) shortly after the dyes were introduced in 1966. Lewis11521 further assumed that the aziridine derivative (III) is capable of further reaction with nucleophilic groups within the fibre, forming crosslinks (IV). Even without the formation of the aziridine intermediate crosslinking can occur, as intermediates (I) and (II) are also capable of reaction with nucleophiles. This has led to the conclusion that the a-bromoacrylamide dyes are essentially bifunctional in nature - subject to steric hindrance and the availability of nucleophilic groups in close proximity to the reactive site.

-68- Chapter Two Quick-Response Methods

,

D - S02 - CH = CH2

l + Peptide - NH,

D-S02-CH2 I CH2 I NH I Peptide

Figure 2.21. Reaction with Hostalan Dyes Chapter Two Quick-Response Methods

D-NH

Cl

F

l + Peptide - NH2

D-NH ONN~F Cl

Peptide-ND

l + Peptide - NH,

D-NH N NH - Peptide ON~ Cl

Peptide-NB

Figure 2.20. Reaction with Drimalan F and Verofix Dyes Chapter Two Quick-Response Methods

Drimalan F and V erofix dyes are considered to be bifunctional in their substitution reactions with the nucleophilic sites in wool, since both fluorine atoms are capable of reaction. The bifunctional character, coupled with exceptional resistance to hydrolysis in the pH region 5-7, leads to a very high degree of dye-fibre covalent bonding and hence to very good wet­ fastness properties of the dyeings. Figure 2.20. shows the simple nucleophilic substitution that occurs. The fluorine atom at the 4 position is more reactive and therefore reacts first, but the reactivity of the fluorine atom at the 2 position is also high enough for further substitution to take place. 11521 Therefore, Drimalan F and Verofix dyes can also produce crosslinks.

With reactive dyes it is very important that they do not react too quickly, and that they achieve a high level of fixation. The level of fixation determines both wet fastness and the economy of application. A slow speed of reaction is required to ensure that the dye is absorbed evenly throughout the fibre prior to fixation occurring. With Lanasol, Verofix and Drimalan Dyes, this occurs via temperature programming of the dyeing cycle. The dyes are not very reactive below 70°C, but they are highly reactive at the boil. Therefore, the dyes are exhausted from the dyebath held at approximately 65°C and when adequate dye absorption has been achieved, the temperature is raised to the boil to promote both reaction and adsorption of the dye remaining in solution. 11531

Hostalan dyes rely on the slow conversion of N-methyltaurine-ethylsulphone to the reactive vinyl-sulphone (Figure 2.21.), which proceeds to completion only at pH 4.5 - 5.5 at 100°C, after one hour. Therefore, Hostalan dyes give very level results, since fixation only occurs gradually at high temperatures. 11521

-69- Chapter Two Quick-Response Methods

The three dye systems outlined above generally satisfy the following criteria:

(a) A high degree of dye-fibre covalent bonding is achieved at the end of the dyeing process, minimising the clearing treatment required to give maximum wet fastness.

(b) The rates of adsorption and of reaction are such that the former is always greater than the latter; otherwise dyeing will be uneven. A dye that is too highly reactive will react rapidly with the fibre even at low temperatures, reducing the possibility for dye levelling or migration; conversely, a dye that is of too low a reactivity will require extended dyeing times at the boil, to ensure adequate covalent bonding and optimum wet fastness. 11491

-70- Chapter Three

EXPERIMENTAL

This chapter summarises the materials, facilities and experimental methods employed in this project.

3.1. Materials for Heat-Transfer Printing

3.1.1. Chemicals

The reactive hydrophobes used in this work were synthesized by Dr C.G. Wang and the methods used can be seen in his work. 11541 The following four reactive hydrophobes were used and examined during this project:

• 2-Bromopropenanilide (AB), • N-1-Naphthyl-2-Bromopropenamide (NNB), • N-2,4-Difluoro-5-Chloropyrimidyl Aniline (AP), and, • N-2,4-Difluoro-5-Chloropyrimidyl p-Toluidine (MAP).

Table A of Appendix 3.1. lists the amines that were employed to form the hydrophobic components of the reactive hydrophobes. Table B of Appendix 3.1. lists the reagents that were used to disperse the reactive hydrophobes in water. Other chemicals used during the application of reactive hydrophobes

-71- Chapter Three Experimental

Commercial Name: C.LName& Molecular Weight Number

Bafixan Red BF Disperse Red 60 317.2

Bafixan Pink FF3B Disperse Red 11 240.2

Bafixan Turquoise G Disperse Blue 347 Not Available

Table 3.1. Dyes Used for Transfer Printing Chapter Three Experimental onto the wool fabric include Lissapol TN450 (ICI) (used as a levelling agent), Drimagen F (Sandoz) and Albegal B (CIBA) (both were used as auxiliary agents and separately recommended as levelling agents). Acetic Acid (80%) (Ajax Chemicals) was also used.

3.1.2. Disperse Dyes

The disperse dyes used to evaluate the transfer printability of the modified wool fabrics were Bafixan Red BF, Bafixan Pink FF3B, and Bafixan Turquoise G. These dyes were chosen because they are in use commercially for the transfer printing of 100% polyester fabrics. The dyes were of commercial grade and were supplied in the liquid form by BASF (Australia). The commercial names of the dyes, along with their colour index names, numbers, and molecular weights are presented in Table 3.1. The chemical structures of the dyes are listed in Appendix 3 .2.

3.1.3. Substrates

The fabric used was 100% wool. The wool was scoured and decatised. The fabric construction was 2/2 Twill botany serge of weight 300 g/m2• The fabric was supplied by John Vickers, Sydney, Australia.

3.2. Facilities

The following is a list of the equipment which was required to carry out the experimentation and to analyse the results.

-72- Chapter Three Experimental

0 Cl N Cl II ~ Ch HN NH OY POCh Cl PCh 0 0 Et3N Cl 300°c NaF 32 atm l

L-NH N F F N F OY L-NH2 OY Cl Cl

F F In which L is the hydrophobic group

Figure 3.1. Synthesis Route for Reactive Hydrophobes Containing the 2,4-Difluoro-5-Chloropyrimidyl Amino Group

(1) Condensation:

CH2Br-CHBr-COCI + NHi-(L) ~ CH2Br-CHBr-CO-NH-(L) + HCI

(2) Dehydrohalogenation:

CH2Br-CHBr-CO-NH-(L) + KOH ~ CH2=CBr-CO-NH-(L) + KBr + H20

in which (L) is a hydrophobic group

Figure 3.2. Synthesis Route for Reactive Hydrophobes Containing the 2-Bromopropenamido Group Chapter Three Experimental

- Dyemaster Laboratory Dyeing Machine (John Jeffreys Engineering Co. Ltd) - LABEC Circulating Oven - Macbeth 2020 Spectrophotometer - Elna Press 3000 - Firsan Thermo Fusing Press Model E6 - Breville Kenwood Chef Mixer Model KM201 C - Mettler Balance - K Hand Coater

3.3. Synthesis and Authentication of Reactive Hydrophobes

As mentioned in Section 3.1.1., the reactive hydrophobes used in this work were synthesised by Dr C.G. Wang, and the methods used are outlined in his work. However, it is beneficial to see the synthesis routes that were used to produce the different hydrophobes. Figure 3.1. and Figure 3.2. give a simple representation of these routes.

The melting points of the reactive hydrophobes were determined under a hot stage microscope. Chemical analysis (C, H, and N), mass spectra and 13C NMR spectra were all carried out by the School of Chemistry, University of New South Wales. Thin Layer Chromatography was carried out using

Merck 60F254 Silica Gel TLC Foils with acetone and butanol (1 :2) as eluents. The chromatograms were observed under UV light in a multilight viewing cabinet (Multilight Ltd., England). The authenticity of these hydrophobes can be seen from the results of these tests. 11551

-73- Chapter Three Experimental

Code: Name: Structure:

N-2 4-Difluoro-5- ' AP Chloropyrimidyl Ar-NH-P Aniline

N-2 4-Difluoro-5- MAP ' Chloropyrimidyl p- CH3-Ar-NH-P Toluidine

AB 2-Bromopropenanilide Ar-NH-COCBr=CH2

NNB N-1-Naphthyl-2- Bromopropenamide C10HrNH-COCBr=CH2

Where: Ar= Phenyl and P = 2,4-Difluoro-5-Chloropyrimidyl

Table 3.2. The Structural Formulae of Reactive Hydrophobes Used in this Work Chapter Three Experimental

3.4. Chemical Modification of the Wool Fabric

The reactive hydrophobes that were synthesised are examples of substantially hydrophobic compounds which consist of both reactive group(s) and hydrophobic groups(s). The chemical structures of these synthesised compounds (Table 3.2.) prevents them from dissolving in water and, consequently, it was necessary to create a dispersion. After considering many experimental recipes it was found that dispersions of moderate viscosity, which could be effectively milled, could be produced using the following formulation: 11091

-10% wt/wt Reactive Hydrophobe -25% wt/wt Matexil DA-AC -8.5% wt/wt Teric PE 68 - 56.5% wt/wt Water

To simulate the milling process, the above components were mixed together in a Breville Kenwood Chef Mixer, Model KM201C. To ensure that the reactive hydrophobes did not melt, intermittent use of the mixer was employed. (i.e. 30 seconds on, 90 seconds off)

Matexil DA-AC (ICI) is an anionic dispersing agent which consists of the di-sodium salt of methylene di-naphthalene sulphonic acid. It is of particular use when dyeing synthetic fibres with disperse dyes. Teric PE 68 (ICI) is a non-ionic dispersing agent of the fatty alcohol poly (ethylene glycol) type.

The recipe that was used to apply the reactive hydrophobes to wool was

-74- Chapter Three Experimental

derived from the methods used by Lewis and Pailthorpe11091 , CIBA11561 , and Sandoz. 11571

-x% o.w.f. Reactive Hydrophobe (from milled dispersion) -4%0.w.f. Acetic Acid (80%) -2% o.w.f. Auxiliary Agent - 6 g/litre Lissapol TN450

The dispersing agent that was employed was Lissapol TN450 (ICI). The auxiliary agents used were Albegal B for the application of 2,4-difluoro-5- chloropyrimdyl amino hydrophobes, and Miralan TOP for the application of 2-bromopropenamide hydrophobes.

3.4.1. Method Used to Apply 2,4-Difluoro-5-Chloropyrimidyl Amino Hydrophobes

The Dyemaster Laboratory Dyeing Machine was heated to a temperature of 40°C. In each dyeing cylinder, 200ml of water, acetic acid (80%), Albegal B and a fabric sample were added. The approximate weight of each sample was 1.9g. The sample was run in the dyebath for 10 minutes and then the well-dispersed 2,4-difluoro-5-chloropyrimdyl amino hydrophobe was added. Over a period of 20 minutes, the temperature of the dyebath was raised to 65°C, and once obtained, was held at this temperature for 2.5 hours. This period of time was considered to be the optimum fixation time. Every half hour or so, water was added to the dye cylinders in order to compensate for that lost due to evaporation. Following fixation, the fabric sample was placed in another bath and soaped. The soaping process employed 1 g/1 Lissapol N for 10 minutes at 99°C and finally the samples were washed off with warm water until free from foam.

-75- Chapter Three Experimental

L-NH F 0 II L - NH - C - C = CH2 I Br Cl

HiN-Wool F Hi}I-Wool -HBr

-HF

L-NH NH-Wool 0 II L - NH - C - HC -CH2 V N Cl I Wool F HiN-Wool l HiN-Wool -HF

L-NH N NH-Wool 0 Wool-NH II I OY L - NH - C - CH - CH2 Cl I NH- Wool

NH-Wool

2,4-Difluoro-5-Chloropyrimidyl Amino 2-Bromopropen Amido (In which L is the hydrophobic group)

Figure 3.3. Reaction Schemes for the Modification of Wool with the Reactive Hydrophobes Used in this Project Chapter Three Experimental

3.4.2. Method Used to Apply 2-Bromopropen Amido Hydrophobes

There are only two differences between this method and the one stated above. Firstly, the initial temperature of the dyeing machine and cylinders was 50°C not 40°C. Secondly, the auxiliary agent added to the dyebath was Miralan TOP not Albegal B. Essentially the timings and temperatures for this method are the same as that for applying the 2,4-difluoro-5- chloropyrimdyl amino hydrophobes.

All of the fabric samples, after they had been rinsed from the soapmg process, were placed in a circulating oven, which was set at a temperature of 95°C, until they were dry. Once dried, they were placed on shelves and left overnight in a humidified room, and weighed 24 hours later.

The reactions of 2,4-difluoro-5-chloropyrimdyl ammo and 2- bromopropenamide hydrophobes with the nucleophilic groups in wool can be seen in Figure 3.3.

3.5. Assessment of Modified Samples

3.5.1. The Determination of the Extent of Modification

Due to the substantially water-insoluble nature of the reactive hydrophobes, they can not be easily measured spectrophotometrically. As a result, the extent of modification was judged from the Weight Gain (WG%) of the fabric and then by determining the moles of reactive hydrophobe grafted on the fabric.

-76- Chapter Three Experimental

3.5.1.1. Percentage Weight Gain

The weight gain (%) can be calculated using the following equation:

Weight Gain(%) = (Wri - Wn) x 100 (3.1) Wn

Wfl and Wa represent respectively the weights of conditioned fabric measured before and after the application of the reactive hydrophobes. As mentioned earlier, all the treated fabric samples were dried to constant weight in a circulating oven at 90°C, and were then left to stand over night in a humidified room. A paper by Lewis and Pailthorpe11681 indicates that for samples with weight gains below 15%, the error is negligible. This proved to be the case for all the wool samples tested.

3.5.1.2. Moles of Reactive Hydrophobes Grafted on the Fabric

In order to determine the moles of reactive hydrophobe grafted onto the wool fabric, it is important to understand a basic law of chemistry, and a simplified model of the reaction that is taking place. Firstly, the basic law:

In any chemical reaction, matter is neither created nor destroyed Therefore, it is possible to conclude that the total weight of the products from the reaction will be exactly equal to that ofthe reactants.

Secondly, the simplified model:

Wool-H + X-M ~ Wool-M + H-X

-77- Chapter Three Experimental

Where: Wool = Wool-H M = Modifier Group H = Hydrogen atom, and X = Leaving Group (halogen atom)

Combining this model with the above law, we can conclude that:

W (Wool-H) + W(X-M) = W (Wool-M) + W(H-X) (3.2)

in which: W(Wool-H) = Initial fabric weight before modification

W(X-M) = Weight of reactive hydrophobe

W(Wool-M) = Final weight of fabric after modification

W(H-X) = Weight ofhaloid acid

From Section 3.5.1.1. we can now conclude that Wn = W(Woot-H) and Wr2

= W (Woot-M)· Or in other words, the increment of fabric weight can be determined thus:

Wn-Wn = W(Wool-M) - W(Wool-H)

= w(X-M) - w(H-X) (3.3)

It is now possible to calculate the quantity of haloid acid [W(H-X)] produced in the reaction:

W(H-X) = Moles of Acid Formed x Molecular Weight of Acid

= Moles of Hydrophobe Reacted x Molecular Weight of Acid

-78- Chapter Three Experimental

b M(X-M) - M(H-X)

M(HF) = 20.0 M(HBr) = 80.9

Modifier M(X-M) b Modifier M(X-M) b

AP 241.6 1.09 AB 226.1 1.56

MAP 255.7 1.08 NNB 276.1 1.41

Table 3.3. Coefficient b Values Chapter Three Experimental

Weight of Hydrophobe X M(H-X) Molecular Weight of Hydrophobe

= w (3.4)

M(X-M)

Where M(H-X) = 20.0 for HF and 80.9 for HBr

Since: Wr2 - Wn = w(X-M) - w(H-X)

= w(X-M) - (W(x-M/M(X-M) X M(H-X)) = w - {W x M)

= W(X-M) X (1 - M(H-X)/M(X-M)) (3.5)

Therefore,

w(X-M) = {Wr2- Wn} x (M(x-M/(M(X-M) - M(H-X))) (3.6)

The coefficients b, for the individual reactive hydrophobes, are given in Table 3.3. Therefore, by using the following formula, it is now possible to calculate the total number of moles of reactive hydrophobe that reacted with a wool fabric of unit weight at any moment.

Moles(X-M) = W

= (Wr2-Wn) x b (3.7)

M(X-M)

-79- Chapter Three Experimental

By rearranging equation 3.1 we obtain:

(Wn-Wn) = WG% x Wn 100%

Substituting this into equation 3.7, we can generate an equation which will determine the moles of reactive hydrophobe grafted on the fabric.

Moles

3.5.1.3. Fabric Handle

Fabric handle is usually assessed by the reaction obtained from the sense of touch. 11581 However, for this experimentation, the bending length values were used as a means of judging the draping quality of the fabric and the change in stiffness after modification. 1159' 1601 The bending length of the samples was determined on a Shirley Stiffness Tester, Serial No. 57 (Shirley Developments Ltd., England), and the bending length of both the warp and weft threads were examined. The dimensions of the samples were 20cm x 2.5cm, and they were all pre-dried in a circulating oven at 100°C for 2 hours. After drying, the samples were conditioned for a period of 24 hours before the fabric samples were tested.

3.6. Transfer Printing

The heat-transfer printing process was divided into two distinct stages. First of all was the production of the transfer paper and secondly, the transfer of the dye from the transfer paper to the modified wool fabric.

-80- Chapter Three Experimental

3.6.1. Stage One: Production of Transfer Paper

Any material that has low substantivity for disperse dyes can be used as a support in the transfer printing process, but the choice falls naturally on paper because of its low cost. The paper surface should be smooth and non­ fibrous and the paper should contain no heavy metals which might act selectively on the dyes. 1771 The paper that was used for this project was bond paper without filling, that had a base weight of 80g/m2• It was supplied by Hexham Textiles Pty. Ltd. [685A Gardeners Road., Mascot, N.S.W., 2020, Australia.]

This paper was then cut into strips, approximately 25cm x 10 cm, in preparation for print paste application. The dyes used were supplied by BASF, (as outlined in Section 3.1.2.) and were mixed with an extender known as Lefixal, (also supplied by BASF) in a ratio of 1:3 (Dye:Extender).

The print paste was then applied to the glazed side of the transfer paper, with the use of a k-hand coater. Draw-downs were then made with a 12µm k-bar (RK Print-Coat Instruments Ltd.) for each of the three colours. These draw­ downs were then allowed to dry, before being cut into squares of dimensions 5cm x 5cm.

3.6.2. Stage Two: Transfer of Disperse Dye to Wool

The transfer paper was then used to apply the disperse dye to the modified wool samples. Both sample and transfer paper were placed in a Firsan Thermo Fusing Press Model E6 for a period of 30 seconds, and at a temperature of 200°C.

-81- Chapter Three Experimental

3. 7. Assessment of Transfer Printed Samples

Having chemically modified the wool fabric and applied the disperse dye to the wool, it is now appropriate to consider the degree of colour transfer and fastness properties.

3.7.1. Colour Transfer

The Kubeika-Munk equation is very useful for determining the degree of colour transfer. It gives the relationship between the ratio K/S and the reflectance R of the substrate. (Where K = Absorption Coefficient, S = Scattering Coefficient, and R = Reflectance). This relationship can be seen in the following equation:

K/S = (l-R)2l2R = kC (3.9)

Therefore, the reflectance can be used to obtain the ratio K/S of the sample. The reflectance (R) of the printed sample was determined on a Macbeth 2020 Spectrophotometer (Petlee Pty. Ltd., 94-98 O'Riordan St, Alexandria, N.S.W., 2015, Australia) which had been calibrated with the following settings: CIE 10 Degree Observer, CIE Lab Colour Scale and CIE D65 Illuminant. An average of ten readings for each sample was used for the calculations.

3.7.2. Fastness Properties

Two fastness properties were examined in this work being fastness to dry cleaning and fastness to light. Wash fastness was not considered, as woollen

-82- Chapter Three Experimental

5% AP AB MAP NNB

10%

...... 15%

------······· · ···· ...... ························ 20% [!] [!] [!] [!]

25%

Figure 3.4. Arrangement of Samples in Preparation for Dry Cleaning Chapter Three Experimental garments are most likely to be dry cleaned. A total of sixty samples were subjected to each test.

3.7.2.1. Colourfastness to Dry Cleaning

The principle behind the dry cleaning fastness test is to examine the loss of colour from the sample and the degree of staining on the undyed cloths attached to the sample. In this case, the degree of staining on the attached wool and cotton fabrics. Initially, a single sample was tested using the Australian Standard AS 2001.4.16, entitled "Determination of Colourfastness to Dry Cleaning Solvents", to determine if the dye would stay fixed to the wool. The dry cleaning process involves the agitation of the sample being tested, with stainless steel balls, in a dry cleaning solvent. The solvent which was used for this test was tetrachloroethylene. The excess solvent was removed from the fabric sample by centrifuging and was dried in air at a temperature of 55°C.

Following this initial test, the sixty fabric samples were divided into three distinct groups, based on the transfer colour of the sample. (i.e. red, pink, and turquoise) Each sample was sewn onto a piece of cotton fabric, with the transfer printed side of the sample facing away from the cotton. The samples were arranged on the cotton fabric in the manner depicted in Figure 3.4. Once the samples were attached to the cotton fabric, a piece of wool fabric of similar size to that of the cotton, was sewn on top of the samples, enclosing them between the cotton and the wool. This was done for each of the three colours. These three fabric samples were then taken to Westley Dry Cleaners and Launderers Pty. Ltd., (154 Barker St, Randwick, N.S.W., 2031, Australia) and subjected to an industrial dry cleaning process using PERC (perchloroethylene ).

-83- Chapter Three Experimental

After allowing the sample and the undyed cloths to return to equilibrium with ambient conditions, it is then possible to assess each sample with a numerical rating.

3.7.2.2. Colourfastness to Light

The principle of the light fastness test is to assess the colour change of fabric samples that have been exposed to an artificial light source, as compared with the colour change of ISO blue light fastness standards. The Australian Standard that was used in this work was AS 2001.4.21., entitled "Determination of Colourfastness to Light Using an Artificial Light Source". Each sample was mounted on a specimen carrier. This is simply a device that provides a suitable means of suspending the test sample and the blue light fastness standards in front of the light source. Half of each sample and the blue standards were covered with an opaque substance. For this work, aluminium foil was used.

The light source that was used for the test was a 500 Watt mercury vapour, tungsten filament, internally phosphor-coated, fluorescent lamp. The specimen carriers were attached to the inside of a black aluminium cylinder, in such a way that they did not overlap each other, and were no closer to the light source than 200mm. It was important to centrally mount the light source in the cylinder so as to ensure a constant distribution of the light around the circumference of the aluminium cylinder.

As irradiation proceeded, the appearance of these samples was observed and compared with the blue standards. Since there were seven blue standards, numbered one through to seven, each of which faded at a different rate, it was possible to match each of the transfer printed samples to the appropriate

-84- Chapter Three Experimental

Dye Class: Trade Name: Colour Index Manufacturer: Number: Acid Acilan Levelling Direct Blue A Acid Blue 25 Bayer

Acid Carbo/an Milling Blue BS Acid Blue 138 ICI

1:1 Metal- Neolan Complex Blue 2G Acid Blue 158 Ciba-Geigy

2:1 Metal- Irgalan Complex Grey BL Acid Black 58 CIBA (Unsulphonated) 2:1 Metal- Acidol Complex Dark Blue Acid Blue 193 BASF (Disulphonated) MTR Reactive Drimalan (dijluorochloro- Blue F-2GL Reactive Blue 94 Sandoz pyrimidyl group} Reactive Lanasol ( a-bromoacryl- Blue 3G Reactive Blue 69 Ciba-Geigy amido group}

Reactive Procion (monochlorotri- Navy HE-R Reactive Blue l 7 l ICI azinyl group)

Table 3.4. Dyes Used On Plasma Treated Wool Chapter Three Experimental standard. Standards one and two showed the first sign of change, and this occurred within 24 hours of the initial exposure of samples to the light source. Standards six and seven were much more resistant to fading, and even after one week, were only slightly affected by the exposure. The samples were exposed to the light source until standard seven showed a change in colour equivalent to grade four on the grey scale for evaluating change in colour. The colourfastness for each of the sixty samples was given a numerical rating between one and seven, depending upon which of the standards it most closely corresponded to.

3.8. Materials for Plasma Treatment of Wool

3.8.1. Substrate

The wool used was the same as that used for the heat-transfer printing work: a 2/2 Twill Botany serge, scoured and decatised, of weight 300g/m2. The 100% wool fabric was supplied by John Vickers, Sydney, Australia.

3.8.2. Dyes

A total of eight dyes were used during this work. As outlined in Section 2.14., there are several dye classes which are capable of dyeing wool. These are acid dyes, chrome dyes, reactive dyes and metal-complex dyes. Within these classes, there are further sub-classes. The dyes selected for this work are representative of the major sub-classes. Table 3.4. outlines the Dye Class, Trade Name, Colour Index Number, and Manufacturer of all the dyes used. Appendix 3.2. shows the dye structures, and Appendix 3.3. outlines

-85- Chapter Three Experimental the auxiliaries and dyeing procedures recommended by the respective dye manufacturers.

3.9. Facilities

The following is a list of the equipment which was required to carry out the experimentation and to analyse the results for the plasma treatment of wool.

- Dyemaster Laboratory Dyeing Machine (John Jeffreys Engineering Co. Ltd) - LABEC Circulating Oven - Macbeth 2020 Spectrophotometer - Conventional Asymmetric Diode Reactive Ion Etching System - Circular Fabric Cutter (Grams Tester)

3.10. Modification of the Wool Fabric with Plasma

3.10.1. Sample Preparation

Before modification could occur, the samples had to be prepared. Several hundred samples were cut using a specially designed fabric cutter, which produced circular fabric samples of diameter 113mm. The water content of the fibres was then minimised by placing the wool samples in a LABEC circulating oven for a period of 24 hours, at a temperature of 40°C. After drying, the samples were sealed in plastic bags until required for plasma treatment.

-86- Chapter Three Experimental

3.10.2. Plasma Apparatus Used

The plasma apparatus employed was a conventional asymmetric diode reactive ion etching system arrangement operating at 8MHz, and using an aluminium chamber with an internal electrode of 120mm diameter. The chamber diameter was 220mm with a height of 50mm. This plasma apparatus was located in the School of Electrical Engineering, University of New South Wales, Sydney, Australia.

3.10.3. Plasma Treatment Conditions and Variables

The wool samples were treated at a pressure of 1 Torr (133 Pascals) with a bias voltage of 120 V de and a flow rate of 400cc/mm oxygen. The two major variables that existed during the plasma treatment of the samples were: i) the length of exposure to the plasma, and, ii) the area of the exposed sample.

Oxygen was the only gas that was used in this work. The plasma exposure times were 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18 and 20 minutes. Three replicate samples were treated for the above mentioned periods of time.

3.10.4. Treatment Procedure

The wool samples were placed inside the aluminium chamber, flat, on the internal electrode. For most of the samples, a rectangular piece of

-87- Chapter Three Experimental aluminium was placed on the surface of the wool as depicted in Figure 3.5. Initially, the dimensions of this aluminium template were 100mm x 50mm. After placing the wool sample and aluminium template in the chamber, the lid was put into place, and the chamber was sealed. The conditions outlined above were then employed, and finally, the wool samples were exposed to the plasma treatment for the required period of time. Following the plasma treatment, the samples were removed from the chamber, clearly labeled, and placed back into sealed plastic bags.

3.11. Tests to Observe the Effects of Plasma Treatment

In order to determine the suitability of the plasma treatment of wool as a realistic possibility for late-stage colouration and quick-response, various tests were essential. These tests revolved around the effects achieved by the use of different dyes, different exposure times, and different ratios of treated to untreated surface areas. The tests that were used are outlined below.

3.11.1. Test to Determine the Effect of Different Dyes

Each particular dye class has a specific recipe for its application. This has been determined in each case by the manufacturer of the dye. The dyeing methods which are outlined in Appendix 3 .3. are those recommended by the manufacturer, and when followed, should result in the optimum dyeing conditions. For each of the dyes used, the following information is given.

-88- Chapter Three Experimental

Firstly, a graphical representation of the temperature in °C of the dyeing at any time. It clearly illustrates the different phases of the dyeing, showing the initial temperature, the rate of temperature increase, and the time required at the boil.

Secondly, there is a written description of the dyeing method which clearly indicates the required conditions, including pH, temperature, ingredients required, and time of application to the dyebath. If these instructions are carefully followed, then optimum dyeing conditions for that particular dye will result.

Finally, there is a short list of calculations for that dye. All the calculations listed are based on a wool sample of 1.75 grams (Average Weight). For each dye used, two concentrations were tested: 0.2% dye and 1.0% dye. The Liquor Ratio (LR) in each case was 50:1 (all percentages on weight of wool).

Since the total weight of wool dyed in each case = 1. 75 grams, then the Total Volume= 50 x 1.75 grams= 87.5 ml.

The initial test conducted on the plasma treated wool was designed to determine which dyes produced the greatest degree of contrast between the treated and untreated sections of the sample. All the samples used for this section of the work were exposed to an oxygen plasma for a period of ten minutes. The samples were dyed in accordance with the relevant procedures outlined in Appendix 3.3., and upon completion of dyeing, were rinsed and then dried in a LABEC circulating oven.

-89- Chapter Three Experimental

50mm

Wool Sample

50% Untreated Aluminium Template

Figure 3.5. Diagrammatic Representation of Aluminium Template 1 and its Placement on the Wool Sample During Plasma Treatment Chapter Three Experimental

3.11.2. Test to Determine the Effect of Different Exposure Times

This test was devised in order to determine the optimum period of exposure for plasma treatment of the wool sample. Procion Navy HE-R was the only dye that was used, and the basis for its selection was that it showed the greatest degree of contrast from the above mentioned test (Section 3.11.1.).

In this test, the wool samples were exposed to an oxygen plasma for the following periods of time: 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18 and 20 minutes. They were all dyed simultaneously with the same auxiliaries and under the same conditions (Refer Appendix 3.3.).

3.11.3. Test to Determine the Effect of Different Treated:Untreated Exposure Areas

This test was devised to observe whether the degree of contrast was affected by the ratio of treated to untreated areas. Initially, a ratio of 1: 1 was employed (i.e. 50% of the sample was treated, and 50% untreated). From the dimensions of the sample observed in Figure 3.5., it is possible to determine the area of the wool sample.

Diameter= 113mm or 11.3cm Radius is therefore = 11.3/2 = 5.65cm Area can be calculated by use of the formula: A = nr2

Therefore, area of wool sample = 7t x ( 5.65cm)2

= 7t x 31.9225cm2 =100cm 2

-90- Chapter Three Experimental

WoolSamvle

56.5mm

______...._ __ ····················

75% Untreated

Woo/Sample

100mm /

Template 3 25% Untreated

Figure 3.6. Diagrammatic Representation of Aluminium Templates 2 and 3 and their Position on the Wool Sample Chapter Three Experimental

In order to achieve a ratio of 1: 1, 50% of the sample needed to be untreated, or in other words, 50cm2• The aluminium template used initially was designed to satisfy this area requirement, and its dimensions were 10cm x 5cm, as depicted in Figure 3.5.

Two other templates were designed in order to observe any trends that may have been evident as a result of different treated:untreated areas. The ratios of all three templates were:

Untreated Treated

Template 1: 1 1 (50cm2:50cm2)

Template 2: 3 1 (75cm2:25cm2)

Template 3: 1 3 (25cm2:75cm2)

The dimensions of the templates relative to the wool samples can be observed in Figure 3.6. Once again, a single dye was used to conduct these tests and it was Procion Navy HE-R. All samples were exposed to an oxygen plasma for a period of 10 minutes.

3.12. Assessment of Colour Parameters

To assess the suitability of plasma treatment as a means of achieving quick­ response and colouration effects, three factors had to be considered. These factors were:

i) the rate of dye uptake of the modified sample compared to that of the untreated sample,

-91- Chapter Three Experimental

ii) the colour difference (~E) between the two, and iii) the fastness properties of them both.

3.12.1. Rate of Dye Uptake

In order to assess the rate of dye uptake, special samples had to be prepared. In this case, an untreated wool sample and a sample which had been exposed to an oxygen plasma for 10 minutes were compared to each other. (The treated sample was modified on one surface only and no templates were used.) A portion of each dyebath was removed for analysis as soon as the wool sample was placed in it, and further portions were removed after 5, 10, 15, 30, 45, 60, 75, 90 and 120 minutes. This was done for all eight dyes. These portions were measured usmg a Cary 3 UV -Visible Spectrophotometer, producing an absorbance value. These values were then used to assess the rate of dye uptake.

3.12.2. Colour Difference

In order to determine the difference in colour between the untreated and treated areas of the wool fabric, the colour was measured using the same Macbeth 2020 spectrophotometer which was referred to in Section 3. 7 .1. CIE Lab colour parameters were calculated for the CIE 10° observer and CIE Illuminant D6s,

The total colour difference (~E) was calculated according to the following equation:

-92- Chapter Three Experimental

8E = 'V (8L *)2 + (8a*)2 + (8b*)2

Where L *, a*, and b*, are the co-ordinates of the CIE Lab colour system. The colour difference (8E) values reported are the means of five readings.

3.12.3. Fastness Properties

Two fastness properties were examined in this work; fastness to washing and fastness to light. Colour fastness to washing was determined by the method specified in AS 2001.4.15-1987, Test B, "Determination of Colour Fastness to Washing - Mild Conditions of Machine Laundering in the Presence of Soap". Assessment of the change in colour of the samples and the staining of the undyed samples was rated using the Grey Scales as specified in AS 2001.4.1-1987. The Australian Standard that was used to test the "Determination of Colour Fastness to Light Using an Artificial Light Source" was AS 2001.4.21., and the procedure was the same as that outlined in Section 3. 7 .2.2.

-93- Chapter Four

RESULTS & DISCUSSION

Two distinct sets of results were obtained for the heat-transfer printing of wool. The first set of results were primarily concerned with how the properties of the wool had altered prior to HTP, whereas the second set of results were more concerned with the level of success of the transfer printing on the wool.

4.1. Assessment of the Modified Fabric

4.1.1. Weight Gain of Wool Samples

From previous work done by Wang11541 , it was found that the maximum weight gain of a sample occurred after a fixation period of 150 minutes. Therefore, in order to obtain this maximum fixation, all the samples treated with the hydrophobes in this work were subjected to this time of fixation.

By using Equation 3.1 in Chapter 3, it was possible to determine the percentage weight gain of all the samples. The weight gains achieved after applying various amounts of 2,4-difluoro-5-chloropyrimidyl amino and 2- bromopropenamido hydrophobes to wool are given in Appendix 4.1.

-94- Chapter Four Results & Discussion

8

7

6

5

~ -0 -....= ~= 4 .c ....-bl) ~ ~ 3

-AB -NNB 2

1

o------+------0 5 10 15 20 25 Reactive Hydrophobe (% o.w.f.)

Figure 4.2. The Extent of Modification versus Applied 2-Bromopropen Amido Hydrophobes Chapter Four Results & Discussion

8

7

6

5 ~ -Q -....= ~ C, 4 ...... c ....t)J) -AP ~ ...... MAP ~ 3

2

1

o------+----- 0 5 10 15 20 25 Reactive Hydrophobe (% o.w.f.)

Figure 4.1. The Extent of Modification versus Applied 2, 4-difluoro-5-chloropyrimidyl Amino Hydrophobes Chapter Four Results & Discussion

Reactive Hydrophobes

Percentage Concentration (o.w.f.) AP MAP AB NNB

5% 3.8% 3.6% 3.1% 2.6% (95% Con f. L.) 0.2% 0.2% 0.2% 0.1%

10% 6.0% 5.1% 4.8% 3.9% (95% Con f. L.) 0.1% 0.1% 0.1% 0.1%

15% 7.1% 5.6% 6.0% 4.8% (95% Conf. L.) 0.2% 0.1% 0.1% 0.2%

20% 7.6% 5.8% 6.9% 5.3% (95% Con f. L.) 0.1% 0.2% 0.1% 0.1%

25% 7.7% 5.9% 7.4% 5.6% (95% Conf. L.) 0.1% 0.1% 0.2% 0.1%

Table 4.1. Average Weight Gain(%) of Wool Samples for each Hydrophobe at Different Concentrations Chapter Four Results & Discussion

(Note: Interpretation of sample codes in Appendix 4.1. The letters A,B,C, and D are representative of the four hydrophobes AP, MAP, AB, and NNB respectively. At any one time, fifteen samples were treated with the reactive hydrophobe, i.e. three samples for each concentration. This meant that two distinct dyeings took place for each hydrophobe, i.e. 2 lots of 15 samples. Therefore, Figures 1 and 2 are representative of either the first dyeing or the second dyeing. Finally, the letters R, P and T are indicative of the colours transferred onto the wool samples, i.e. R = Red, P = Pink, and T = Turquoise.)

Table 4.1. shows an average of these results, and these in tum have been represented graphically in Figures 4.1. and 4.2.

From an examination of the data presented in the table and the graphs, it can clearly be seen that the percentage weight gain of the samples increases as the applied concentration of reactive hydrophobe increases. This is by no means surprising as a greater concentration of hydrophobe in the dyebath would encourage greater levels of hydrophobe fixation on the wool. This in tum would increase the percentage weight gain. It should also be noted that as the concentration of the hydrophobe added to the dyebath increases, the degree of percentage weight gain increase diminishes. That is, a linear relationship does not exist. This can be seen quite clearly by the curve of the graphs, and is also not surprising. As the hydrophobe exhausts and fixes onto the wool, it has the effect of blocking the hydrophilic sites in the wool. As more and more hydrophobe exhausts onto the wool, the number of hydrophilic sites available diminishes. Consequently, with fewer sites, less hydrophobe is grafted onto the wool, and this results in a smaller increase in percentage weight gain. The presence of competing reactions such as hydrolysis, where the reactive compound has hydrolysed due to the presence of water, may have contributed to the poor uptake of reactive hydrophobe.

-95- Chapter Four Results & Discussion

10

9

8

7

e 6 =,. bi)

~ --~ 5 -0 ....e ....- ~ 4

3 -AB -+-NNB

2

1

0 ----+---+----1------ir-----l 0 5 10 15 20 25 Reactive Hydrophobe (% o.w.f.)

Figure 4.4. Average Number of Millimoles of 2-Bromopropen Amido Hydrophobes Grafted onto the Wool Fabric at Different Concentrations Chapter Four Results & Discussion

7

6

5

4 !r.. ~ ~ ~ 0 -....5 -i 3 -AP ~MAP

2

1

0------0 5 10 15 20 25 Reactive Hydrophobe (% o.w.f.)

Figure 4.3. Average Number of Millimoles of 2, 4-difluoro-5-chloropyrimidy I Amino Hydrophobes Grafted onto the Wool Fabric at Different Concentrations Chapter Four Results & Discussion

Reactive Hydrophobes

Percentage Concentration (o.w.f.) AP MAP AB NNB

5% 3.3 2.9 4.1 2.6 (95% Conf. L.) 0.2 0.1 0.2 0.1

10°/o 5.2 4.2 6.4 3.8 (95% Conf. L.) 0.1 0.1 0.2 0.2

15% 6.2 4.6 8.0 4.7 (95% Con f. L.) 0.2 0.2 0.2 0.1

20% 6.6 4.7 9.2 5.2 (95% Conf. L.) 0.1 0.1 0.2 0.1

25% 6.6 4.8 9.8 5.5 (95% Conf. L.) 0.1 0.1 0.2 0.2

Table 4.2. Average Number of Moles of Reactive Hydrophobe (x 10-3) Grafted onto the Wool Fabric at Different Concentrations Chapter Four Results & Discussion

4.1.2. Moles of Reactive Hydrophobe Grafted onto the Fabric

The percentage weight gam due to the modification of wool can be converted into moles of reactive hydrophobe grafted onto the wool fabric on the basis of Equation 3.8. This equation states:

Moles(X-M) - WG% x Wn x b

M(X-M) x 100%

The complete results from this calculation can be seen in Appendix 4.2. Table 4.2. shows the average of these results, and these in turn have been represented graphically in Figures 4.3. and 4.4.

Once again, by examining the data presented in the table and the graphs, it is possible to observe distinct trends. The number of moles of reactive hydrophobe grafted onto the wool fabric increases as the applied concentration of reactive hydrophobe increases. However, the number of moles that are grafted onto the wool, diminish with increasing concentration of hydrophobe. The reason for this is exactly the same as that outlined in the previous section on percentage weight gain.

The results show that the two reactive hydrophobes produced by the aniline derivatives, (i.e. AP and AB), gave the best overall results for both percentage weight gain and number of moles grafted onto the wool fabric. It is easier to comprehend these results after considering the individual character of the reactive hydrophobes employed.

-96- Chapter Four Results & Discussion

4.1.3. The Extent of Modification and Character of Modifiers

The extent of modification is largely determined by the character of the modifier that is employed. The modifiers are uniquely characterized by the reactivity of the reactive system, Inorganity - Organity Ratio (IOR) values of the hydrophobic group, and the size of the hydrophobic group. These characteristics are outlined below.

i) The reactivity of the reactive system

The rate at which the reaction takes place is directly related to the reactivity of the reactive system. The greater the reactivity of the reactive system, the faster the reaction occurs. Work done by Lewis and Pailthorpe11091, on 2,4- dichloro-s-triazinyl hydrophobes and Wanglllll, on 2-bromopropenamido and 2,4-difluoro-5-chloropyrimidyl amino hydrophobes shows that the order of the modification rate of these hydrophobes is consistent with the following known reactivity order of the reactive systems.

2,4-dichloro-s-triazinyl > 2-bromopropenamido > 2,4-difluoro-5-chloropyrimidylamino

ii) The IOR value of the hydrophobic group

The extent of modification is also dependent on the affinity of the modifier for wool. This can easily be determined through the use of IOR values. These values are simply calculated by dividing the inorganitic value, and this is done for both the modifiers and the wool. The closer the IOR value

-97- Chapter Four Results & Discussion

Amine Chemical /OR Value Corresponding Structure Hydrophobes

Aniline ArNH2 0.71 AP/AB

1-Naphthylamine Nf-(1)-NH2 0.65 NNB

p-Toluidine CH3ArNH2 0.61 MAP

Table 4.3. The IOR Values of Amines Used

Ar= Phenyl

Nf-(1)- = 1-Naphthyl Chapter Four Results & Discussion of the modifier is to that of the wool, the greater the affinity and hence the quicker the exhaustion proceeds.

The three amines that were used to form the hydrophobic components of the modifiers are listed in Table 4.3., along with their chemical structure and IOR value. Of these three amines used, the hydrophobic character of aniline is the lowest, and p-toluidine is the highest. This observation is supported by the IOR value of the amines used, i.e. the affinity of the modifier to wool is dependent upon how close the IOR value of the modifier is to that of the wool. The lower the hydrophobic character of the amine, the greater the number of moles that will be absorbed and grafted onto the wool.

Hydrophobic Character: AB

No. ofMoles Grafted onto the Wool: AB>AP>NNB>MAP

/OR Values: 0. 71 = 0. 71 > 0.65 > 0.61

IOR values of the amines employed are consistent with the number of moles grafted onto the wool, and give a reasonably accurate indication of how effective the reactive hydrophobe will be. From the IOR values 11691 it is possible to conclude that the wool samples treated with reactive hydrophobes AB and AP will give the best results for transfer printing, due to the high number of moles grafted onto the wool. This conclusion is supported by the results outlined on Section 4.2.1.

-98- Chapter Four Results & Discussion iii) The size of the hydrophobic group

The size of the hydrophobic group is an important factor when considering the number of moles that have been grafted onto the wool. The bulkier the hydrophobic group, the more difficult it is for the modifier to penetrate the wool fibre and attach itself to the hydrophilic sites. This can be seen by examining the four hydrophobes used. Firstly, the 2-bromopropenamido hydrophobes:

AB => C6Hs - NH - COCBr = CH2 (2-Bromopropenanilide)

NNB => C10H1 - NH - COCBr = CH2 (N-1-N aphthyl-2-Bromopropenamide)

Secondly, the 2,4-difluoro-5-chloropyrimidyl amino hydrophobes:

AP => C6Hs - NH - P (N-2,4-Difluoro-5-Chloropyrimidyl Aniline)

MAP=> CH3-C6H4-NH-P (N-2,4-Difluoro-5-Chloropyrimidyl)

Where P = 2,4-Difluoro-5-Chloropyrimidyl

In both instances, the bulkier of the two ammes, 1.e. NNB and MAP, resulted in the least number of moles of reactive hydrophobe being grafted onto the wool. This is consistent with what was expected.

-99- Chapter Four Results & Discussion

Hydrophobe AP AB MAP NNB % Application (o.w.f.) 0%, 14.18 14.18 14.18 14.18 5% 29.27 25.43 28.41 35.54 10% 30.89 26.18 32.34 44.23 15% 31.20 26.70 32.93 49.72 20% 31.65 26.89 33.59 52.87 25% 31.91 26.99 34.02 55.45

Table 4.4. Yellowness Index (YIE) at Different Application Levels of the Four Reactive Hydrophobes Chapter Four Results & Discussion

60..------,

50

40 -~ -C'., ~ ~ ~AP "O C: ....._AS 30

10 t

0 +-----r------T------.------..---~ 0 2 4 6 8 10 Millimoles

Figure 4. 7. Yellowness Index (YIE) Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Chapter Four Results & Discussion

5~------,

4 i

~ - 3 ei:..> '-' r .c --0--AP bJ) -+-AS Q) _...,_MAP ..;i= -0--NNB ....ell "0= 2 ==Q)

0 +------,---~-----r----+------1 0 5 10 15 20 25 % Application Level of Hydrophobe (o.w.f.)

Figure 4.6. Bending Length versus % Application Level of Reactive Hydrophobe (o.w.f.) on Wool Fabric - Weft Side Chapter Four Results & Discussion

5~------~

4

rr., - 3 t ~ eu + '-" .c ~AP bi) C: --e--AB Q) _...,_MAP ~ 01) -0-NNB ....C: '0 C: 2 =Q)

r

0 -r------,r-----r------r------r------1 0 5 10 15 20 25 % Application Level of Hydrophobe (o. w. f.)

Figure 4.5. Bending Length versus % Application Level of Reactive Hydrophobe (o.w.f.) on Wool Fabric - Warp Side Chapter Four Results & Discussion

4.1.4. Fabric Handle

The modified fabric samples were subjected to a bending length test in order to assess the fabric handle. By comparing the untreated wool fabric with the treated wool, at different concentration levels, it was possible to observe variations in bending length, and hence the change in draping quality and stiffness of the fabric. The bending length determines the manner in which the fabric drapes, and also how stiff the samples areY 701 Figures 4.5. and 4.6. graphically represent the bending length versus the percentage application of reactive hydrophobe (o.w.f.) for AP, AB, MAP, and NNB modified wool fabrics, in both the warp and weft directions respectively.

The graphs indicate that for all hydrophobe modified samples, the bending length increases with increasing concentration of hydrophobe, but only marginally. Thus, as more hydrophobe is applied, the stiffness of the fabric increases. However, this increase is by no means significant, and consequently, there is no distinguishable difference in handle between untreated and treated samples. The results plotted are an average of three readings.

4.1.5. Yellowness Index

The plot of yellowness index (YIE) versus millimoles of reactive hydrophobe (millimoles/gram) grafted on wool for AP, AB, MAP and NNB modified wool fabric, is given in Figure 4.7., and the YIE values can be seen in Table 4.4.

-100- Chapter Four Results & Discussion

A slight degree of yellowing occurred in all cases, however, the most notable was evidenced with reactive hydrophobe NNB. This discolouration in the appearance of the wool fabric has been attributed to the colour of the reactive hydrophobe. Hydrophobes AP, MAP, and AB were all very close to transparent, whereas NNB was a blue-grey powder. It is also apparent from the data in Table 4.4. that the percentage application level of reactive hydrophobe had a distinct effect in the case of NNB, and this is also noted with the other hydrophobes, but to a much lesser extent. It is therefore possible to conclude that the yellowness index increases with increased hydrophobe application.

4.2. Assessment of the Transfer Printed Fabric

The heat transfer printability of wool fabric, modified with AP, AB, MAP, and NNB hydrophobes, was examined using three disperse dyes viz., Bafixan Red BF, Bafixan Pink FF3B, and Bafixan Turquoise G. The selection of these dyes was made on the basis that they are all in commercial use for the heat transfer printing of 100% polyester fabric. After applying the transfer print to the chemically modified wool samples, it was then necessary to examine the degree of colour transfer and the fastness properties of all these samples.

4.2.1. Colour Transfer

The degree of colour transfer can be easily determined through the use of the Kubeika-Munk equation. (Refer Section 3.7.1.) The K/S values were

-101- Chapter Four Results & Discussion

Disperse Turquoise G Samples

2

§ ~AP 0 lt) ~AB IC ...... 1.5 -.-MAP ~ -0-NNB rJJ --~

0 2 4 6 8 10 Millimoles

Figure 4.10. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Turquoise G Chapter Four Results & Discussion

Disperse Pink FF3B Samples

3~------,

2.5 t +--

2

e C: -o-AP 0 -+-AS ll) "".... 1.5 ---...-MAP ~ --0--NNB rri --~

0.5 i

0 +------.------.----+------+---~ 0 2 4 6 8 10 Millimoles

Figure 4.9. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Pink FF3B Chapter Four Results & Discussion

Disperse Red BF Samples

2.5 - -l-

2

8 -<>--AP 0= -+-AB ll) ""...... 1.5 j ---....-MAP ~ -0--NNB rfj ---~ I +- +

0.5

o------~---~------< 0 2 4 6 8 10 Millimoles

Figure 4.8. K/S Versus Millimoles of Reactive Hydrophobe (millimoles/gram) Grafted on Wool Before Dry-Cleaning - Disperse Red BF Chapter Four Results & Discussion determined usmg a Macbeth 2020 Spectrophotometer, by usmg the reflectance values at the wavelength of maximum absorption. This value varied for each of the three disperse dyes that were examined:

520nm Bafixan Red BF, 540nm for Bafixan Pink FF3B, and

650nm for Bafixan Turquoise G.

The K/S values for all the transfer printed wool samples before any fastness tests were conducted, are tabulated in Appendix 4.3., and these are graphically represented in Figures 4.8., 4.9., and 4.10.

Without exception, all four hydrophobes demonstrated an ability to increase the affinity of the disperse dyes to the wool. This was expected as the aim of modifying the fabric was to increase the hydrophobic character of the wool and thus, increase the affinity of the disperse dyes. An obvious modification can be seen by comparing the unmodified wool samples with those which have a 5% application level of hydrophobe. The three graphs clearly indicate this increase in affinity by the increase in K/S values, which is representative of increased colour transfer.

All three graphs also indicate that reactive hydrophobe AB was the most

successful in increasing dye affinity. This result is supported by earlier data which showed that hydrophobe AB gave the greatest number of moles grafted onto the wool. These two observations indicate that samples which were modified with hydrophobe AB, resulted in a greater degree of hydrophobic character.

-102- Chapter Four Results & Discussion

Dry-Cleaned Disperse Turquoise G Samples

2.5 ..------,-----,

2 +

1.5

Q ~AP 0= II) __._AB \0 .... ___..._MAP ~ -0--NNB rJ:J --~

0.5

0+------T------.----..------T------i 0 2 4 6 8 10 Millimoles

Figure 4.13. K/S Versus Millimoles of Reactive Hydrophobe (o.w.f.) Grafted on Wool After Dry-Cleaning - Disperse Turquoise G Chapter Four Results & Discussion

Dry-Cleaned Disperse Pink FF3B Samples

2.5 ~------~

2

1.5 + 8 ---0---AP 0= '<:I' -+-AB l/) ..... -.-MAP ~ --0--NNB rJJ ---~

0.5

0 -t------...----r------+-----r------1 0 2 4 6 8 10 Millimoles

Figure 4.12. K/S Versus Millimoles of Reactive Hydrophobe (o.w.f.) Grafted on Wool After Dry-Cleaning - Disperse Pink FF3B Chapter Four Results & Discussion

Dry-Cleaned Disperse Red BF Samples

2.5 ..------,-----,------,

2

e 1.5 C: I ~AP 0 N -+-AS II) ..... --.-MAP ~ I -0--NNB 00 ---~ t

0.5

0 +------1----+------.----+------t 0 2 4 6 8 10 Millimoles

Figure 4.11. K/S Versus Millimoles of Reactive Hydrophobe (o.w.f.) Grafted on Wool After Dry-Cleaning - Disperse Red BF Chapter Four Results & Discussion

Although a reasonable degree of dye transfer was obtained on all the modified samples, it is clear from the graphs that hydrophobes MAP and NNB were not as successful at increasing the hydrophobic character of the wool in comparison with hydrophobes AB and AP. By comparing the three different dyes used, it becomes apparent that the trends are fairly consistent with each other, however, the degree of colour transfer varies. Bafixan Red BF exhibited the greatest degree of colour transfer, for all the modified samples.

4.2.2. Dry-Cleaning Fastness

All the transfer printed wool samples were subjected to a dry-cleaning fastness test. After the completion of the dry-cleaning process, the K/S values for all the samples were obtained using the spectrophotometer. These values have been tabulated in Appendix 4.4., and have been graphically depicted in Figures 4.11., 4.12. and 4.13.

In the three graphs, the K/S values have been plotted against the millimoles of reactive hydrophobe (millimoles/gram) grafted on the wool. The trends that are interpreted from these graphs give a much more accurate indication of how effective the hydrophobes have been. This is because the dry­ cleaning process removes the unfixed dye, and leaves just what is fixed to the wool. After dry-cleaning, the two hydrophobes AB and AP were still the most successful in increasing dye affinity.

When the K/S values are plotted against the percentage weight gain of the samples, the trends are also consistent with these findings. This can be seen in Appendix 4.5.

-103-

= =

o· o·

n n

C C

"' "'

"' "'

0 0

;,;;· ;,;;·

Re> Re>

C C "' "'

= =

t'!) t'!)

"' "'

:::0 :::0

., .,

C C

0 0

""l ""l

., .,

t'!) t'!)

I>:> I>:>

-

:r :r (j (j

"O "O

% %

% %

0

% %

% %

15% 15%

25% 25%

2

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•

0

010

•

. 00

-

With With

fl

Dyed Dyed

NNB NNB

Wool Wool

t-

Modified Modified

:

G G

l

MAP MAP

Hydrophobe Hydrophobe

Turquoise Turquoise

for for

Hydrophobe Hydrophobe

Disperse Disperse

Values Values

I I

AB AB

1 1

-:-

Lightfastness Lightfastness

1

4.16. 4.16.

I I

AP AP

: :

1

Figure Figure

------~ ------~

0 0

5 5

2 2

3 3 5 5

4

.

.

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3

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= =

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er., er.,

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~ ~ · (j ::r Figure 4.15. Lightfastness Values for Hydrophobe Modified Wool Dyed With '0~ Disperse Pink FF3B -.,tl) "%1 0 4.5 .------,------...... - .,C

4

3.5

3 00 % .5 % ~ 2.5 0 10% C ..... • 15% ·-c,: ~ 2 020 % •25 %

1.5

:;::, tl) "'C ;::;:- "' Ro S'. 0 "'l"l C "' "'5· AP AB MAP NNB ::, Hydrophobe f!>

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AB

Lightfastness

4.14.

AP

Figure

5

5

5 4 3

5

2

5

.

.

.

.

4 3

1.5

2

0

~

C:

Oil ~

..

~

.... Chapter Four Results & Discussion

AP AB MAP NNB Hydrophobe p p p p % R T R T R T R T Application

0% 1-2 1-2 1 2 1-2 1-2 1-2 1 1 1 1 1

5% 3 3-4 2-3 3-4 3-4 3 2-3 2-3 2 1-2 1-2 1

10% 3 4 3 3-4 4 3-4 2-3 3 2-3 2 2 1

15% 4 3-4 3 4 4 3-4 3 2-3 2-3 2 1-2 1-2

20% 4-5 4 3 4 4-5 4 3 3 3 2-3 2 2

25% 4-5 4 3-4 4-5 4-5 4 3-4 3-4 3 3 2-3 2

Table 4.5. Light Fastness Values for Hydrophobe Modified Wool which has been Transfer Printed with Three Different Disperse Dyes

Note: R = Disperse Red BF, P = Disperse Pink FF3B, and T = Disperse Turquoise G. Chapter Four Results & Discussion

4.2.3. Light Fastness

Sixty modified wool samples were exposed to the light source as specified in the methodology outlined in Section 3.7.2.2. The values obtained for each sample have been recorded in Table 4.5. and are graphically represented in Figures 4.14., 4.15 ., and 4.16.

A number of trends become instantly apparent upon examining these results. Firstly, as the concentration of hydrophobe applied increased, so too did the light fastness rating. The samples which obtained the foremost degree of fastness in almost all instances were at the 25% o.w.f. application level of the hydrophobe.

Secondly, in almost all cases, the samples which were transfer printed with the Bafixan Red BF or Bafixan Pink FF3B dyes gave better light fastness results than those which were transfer printed with the Bafixan Turquoise G dye.

Finally, by comparing the results obtained for the different hydrophobes, it is possible to conclude that some hydrophobes enhance the light fastness of the dyes better than others. The results obtained from this work indicate that the hydrophobes can be ranked from most effective to least effective as follows: AB, AP, MAP, and NNB.

Also worth noting is the effect of light on the discolouration of the wool substrate. Samples treated with hydrophobe NNB were by far, the worst offenders. A very distinctive yellowing of the wool occurred, which is also, a less than desirable property.

-104- Chapter Four Results & Discussion

Before examining the results obtained from the various tests outlined in Section 3 .11. (Tests to Observe the Effects of Plasma Treatment), it is important to briefly consider the role of fibre structure in wool dyeing.

4.3. Role of Fibre Structure in Wool Dyeing

4.3.1. Mechanism of Wool Dyeing

When wool is dyed by an exhaustion method there are three distinct stages of movement of the dye:11 611

i) diffusion of the dye through the dye bath to the fibre surface,

ii) adsorption of the dye onto the fibre surface, and,

iii) diffusion of the dye from the surface to the fibre interior.

The circulation rate of the dye liquor largely determines the rate at which the dye is supplied to the fibre surface. The adsorption of the dye onto the fibre surface is affected by such factors as the characteristics of the particular dye, the pH of the dyebath and the presence of inorganic salts and surfactants. All three of the above mentioned stages occur during the exhaust dyeing of wool, and the overall rate of dyeing is ultimately influenced by the slowest of the three steps.

-105- Chapter Four Results & Discussion

4.3.2. The Role of the Cuticle in Wool Dyeing

In order to obtain satisfactory shade development and fastness properties, complete penetration of dye into the fibre interior is essential. Early researchers identified that the cuticle acted as a barrier, greatly inhibiting this penetration. They assumed that the cuticle was a continuous membrane and that the dye had to pass through it. This proved to be incorrect when it was discovered that intercellular material extended to the exterior of the fibre, thus creating gaps between the scales. It is the existence of these gaps which makes it possible for dyes to penetrate the wool without diffusing through the cuticle.

Upon closer examination of the cuticle, it was discovered that surface lipids near the edges of cuticle cells,11 621 and at the intercellular junctions11631 were responsible for hindering dye diffusion into the nonkeratinous regions of the cell membrane complex. The highly crosslinked A-layer of the exocuticle is

also thought to be responsible for inhibiting dye diffusion. 1164•1651 In order to speed up the dyeing process, this barrier needs to be targeted. Substantial chemical and physical modification of this barrier has already been researched. Some examples of these modifications include:

- a reduction of the A-layer of the exocuticle,11641 - complete removal of the cuticle, 11661 - severe surface abrasion, 11641 and, - extension of the wool fibres. 11671

In this work, plasma treatment was used to modify the above mentioned barrier. The results of this modification are outlined in the following sections.

-106- Chapter Four Results & Discussion

0.9 - --l-- -+-

0.8 - +

..-.. 0.7 J c..: -+- I ~ 0.6 L + .s, -+-Treated 0.5 l .~ QJ ..... ---Untreated Q 0.4 I ~ 0.3 0.2 j 0.1 1 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17g Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Lanasol Blue 3G

0.9 0.8 t -c..:. 0.7 ~ 0.6 t 0 -+-Treated 0.5 -.....QJ t ---Untreated Q ~ 0.3 0.2

0.1

15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17h Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - Procion Navy HE-R Chapter Four Results & Discussion

0.9

0.8 c..:-- 0.7 ~. 0.6 0 -+-Treated 0.5 --aJ -II- Untreated ;..., Q '&. 0.3 0.2

0 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17e Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Acidol Dark Blue MTR

l ··~-i------~ 0.9 +

0.8 + c..:~ 0.7 ~ 0.6 -.S- -+-Treated 0.5 -j­ 1 i aJ -II-Untreated s 0.4 - t t t '&. 0.3 + t 0.2 t j t 0. ~ IIIF"';..._-----'------'-t __t _ __...1__ +__ .,..------1 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17f Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Drimalan Blue F-2GL Chapter Four Results & Discussion

0.9 -1- -+- 0.8 -+- --t j_ c..: 0.7 t ~ + t-= - I ~ 0.6 --t -+ + +- I -r 0 -+-Treated 0.5 .. + _j__ ;- -a.I.... I -II-Untreated Q 0.4 -+ T I ~ 0.3 +- -+ + -1-

0.2 ./- 0. 1 t t 0 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17c Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Neolan Blue 2G

0.9

0.8 -c..:. 0.7 ~. 0.6 0 -+-Treated 0.5 - r -a.I.... -II-Untreated Q 0.4 f ~ 0.3 t t 0.2 - j

0.1 ~ 1 0 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17d Comparison of% Dye Uptake Between Plasma Treated and Untreated Wool Samples - lrgalan Grey BL Chapter Four Results & Discussion

0. 9 + ~ +--

0.8 t ~ -+ + -+

_j_ -c...: 0.7 -t- t ~ 0.6 . ~- 0 0.5 --,- _j_ i+ --....,QJ l -+-Treated Q 0.4 -I- + i --+ ---Untreated ~ 0.3 +- ~ f + + 0.2

0.1 + +

0 I 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17a Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Acilan Direct Blue A

0.9

0.8

~ 0.7

~ 0.6 -+-Treated ,£, 0.5 QJ...., ---Untreated Q 0.4 1 ~ 0.3 l 0.2 j 0.1 t

0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.17b Comparison of % Dye Uptake Between Plasma Treated and Untreated Wool Samples - Carbolan Blue BS Chapter Four Results & Discussion

4.4. Dyeing of Plasma Treated Wool

Many researchers have observed that plasma treated wool dyes differently to untreated wool. These observations have shown that the rate of dye uptake is higher, and the depth of colour is often greater as a result of this modification. Both of these observations are worth examining in more detail for the following two reasons. Firstly, any modification of the wool that increases the rate of dyeing is a positive step in achieving quick­ response. Secondly, a modification that produces a contrast in shade also opens up possibilities of colouration effects.

The tests employed were specifically designed to examine the rate of dye uptake, the colour difference, and the fastness properties of plasma treated wool compared to that of untreated wool using:

a) representative dyes from different classes, b) different periods of plasma exposure time, and, c) different exposure areas.

4.4.1. Effect of Different Dyes

The dyes that were chosen for this experiment are outlined in Table 3.4. The basis for their selection was that they were representative of the major sub­ classes for dyeing wool. Figures 4.17.(a-h) demonstrate the rate of dye uptake for each of the eight dyes, showing the difference between unmodified and ten minute oxygen plasma treated wool. (All graphs are

-107- Chapter Four Results & Discussion representative of 1% o.w.f. dye concentrations) For every dye tested, without exception, the rate of dye uptake was higher for the treated sample compared to that of the untreated.

Of the eight dyes that were tested, only two demonstrated a minimal increase in the rate of dye uptake, being Acilan Direct Blue A and Neolan Blue 2G. With the other six, a clear increase in the rate of dye uptake was apparent. Not only was the rate of dye uptake higher, but the percentage dye uptake was greater for all the modified samples.

The most noticeable example of this was with the samples that were dyed with Procion Navy HE-R. The percentage dye uptake of the modified wool sample was greater after 60 minutes than the unmodified wool sample after 120 minutes. (refer Figure 4.17.h) This demonstrates a significant saving in dyeing time.

Time is not the only saving. By-products of a more efficient dyeing process are greater production capabilities, lower energy requirements, and lower wage costs. In addition to these savings is the reduced cost of dyes. Greater depth of colour was achieved for all modified samples, resulting in a lower dye requirement.

From the results obtained in this work it is possible to deduce conclusively that both the rate of dye uptake, and the percentage dye uptake, increase as a result of oxygen plasma modification of the wool surface. However, the degree of increase in both cases is different for each class of dye. The colour difference between treated and untreated samples will now be considered.

-108-

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8 8 - Chapter Four Results & Discussion

Dye Trade Name i1E 0.2% Dye i1E 1.0%Dye

Acilan Direct Blue A 1.5 3.1

Carbo/an Blue BS 3.7 5.5

Neolan Blue 2G 2.3 3.8

Irgalan Grey BL 5.3 7.1

Acidol Dark Blue MTR 7.8 9.4

Drimalan Blue F-2GL 4.1 4.8

Lanasol Blue 3G 4.1 4.2

Procion Navy HE-R 11.5 13.0

Table 4.6. Colour Difference (L1E) Between Untreated and Treated Wool Samples Dyed at 0.2% and 1.0% Dye Concentrations - Treatment: Exposure to an Oxygen Plasma for 10 Minutes. Chapter Four Results & Discussion

In order to determine the colour difference (8E) between the treated and untreated wool samples, a Macbeth 2020 spectrophotometer was used to calculate the CIE Lab colour parameters. The L *a*b* values can be seen in Appendix 4.6., the 8E values are summarised in Table 4.6., and have been presented graphically in Figure 4.18.

The results indicate that the colour difference is always greater for the 1.0% dye samples than for the 0.2% dye samples. More importantly, it highlights those dyes which produced the most significant colour difference between the treated and untreated samples. Of the eight dyes used, Procion Navy HE-R and Acidol Dark Blue MTR produced the most significant colour difference, whereas Acilan Direct Blue A and Neolan Blue 20 produced the least significant colour difference. This result is by no means surprising as it is consistent with the results obtained for both the rate of dyeing and percentage dye uptake.

4.4.1.1. Discussion

Section 1.2. gave an overview of the morphological structure of wool. In particular, it outlined the three main components of the cuticle namely the epicuticle, exocuticle and endocuticle. The epicuticle and exocuticle work together to form a resistant barrier to the penetration of dyes. The plasma treatment of wool is a surface-specific modification and in no way affects the cells of the cortex. It does, however, have a significant effect on the cells of the cuticle. Extensive surface analysis of wool fibres treated with different plasma gases has been conducted with the use of a transmission electron microscope. These investigations showed that plasma treatment modifies the A-layer of the exocuticle. The formation of grooves was clearly visible which suggests that partial degradation had occurred. These grooves result in a greater surface area for the dyes to diffuse into the wool.

-109- Chapter Four Results & Discussion

The A-layer contains the highest level of cystine in the fibre. Since the disulphide bonds of cystine form crosslinks, it is possible to conclude that the A-layer is the most highly-crosslinked component of the wool fibre.

This conclusion is supported by Baumann and Setiawan11651 , who argued further that the highly-crosslinked keratinous proteins of the exocuticle were responsible for restricting the diffusion of dye molecules.

The results obtained suggest that the number and therefore the density of the crosslinks in the fibre surface are reduced as a result of oxygen plasma treatment. It appears that the cystine residues present in the cuticle have been oxidised, resulting in cysteic acid residues.

I I oc co I I HCCH2S - SCH2CH I I H~ ~H

Cystine Residue Cysteic Acid Residue

The epicuticle of the wool fibre is strongly hydrophobic and limits the rate of dye uptake. It has been suggested that the affinity of the fibre for dyes is significantly increased after plasma modification due to the hydrophilization of the fibre surface. This factor, combined with the reduction of cross-links in the exocuticle, works together to reduce the natural barrier formed by the cuticle.

This modification of the cuticle after plasma treatment enables the dye to diffuse into the fibre both intercellularly (between the cells) and transcellularly (through the cells). Now the dye has two different pathways

-110- (":) Figure 4.19. Plot of Delta E versus Molecular Weight ::r I>) "C ~ 8.------~ "rl 0 C lrgalan ~ 7

6

5 I ~

~ .5 4 ~ Q-

3 ~ ~ ~ --"- Acilan

I 2 ~ ------+- +- --t T I I I ::0 ~ 1 I -, __J_ -, - j _L --,- - I I[ "'- R'> 0 i;;· 0 n C 0 100 200 300 400 500 600 700 800 900 1000 "'o· Molecular Weight ::, Chapter Four Results & Discussion to choose from when diffusing into the fibre, as opposed to one for the untreated wool. The creation of this second pathway would most certainly increase the rate of dye diffusion, as evidenced by the above mentioned results.

Another interesting observation was made by comparing the molecular weights of the dyes. Unfortunately, it was not possible to obtain this information for the reactive dyes, only their reactive groups. The molecular weights and their corresponding ~E values from Table 4.6. (1.0% dye concentrations o.w.f.) for the first four dyes are given in Table 4.7.

Dyes: Molecular Weights: LIB: Acilan Direct Blue A 416.3 3.1 Carbolan Blue BS 687.6 5.5 Neolan Blue 2G 518.3 3.8 Jrgalan Grey BL 900.9 7.1

Table 4.7. Comparison of Molecular Weight and liE

This information is presented graphically in Figure 4.19. The trend from the graph indicates that the colour difference increases as the molecular weight mcreases. (Appendix 4.7. shows how the molecular weights were determined).

The above trend suggests that the plasma modification enhances the diffusion of larger dyestuffs, such as Irgalan dyes, into the fibre. Prior to modification, the dyestuffs were restricted to intercellular diffusion. The thickness of the intercellular cement between the scales is very small, and hence the rate of diffusion of dyestuffs can be affected by the size of the dye molecule.

-111- Chapter Four Results & Discussion

As would be expected, the dye molecules are going to favour those regions of the fibre where diffusion is easier. Consequently, a greater portion of the dye molecules diffuse where the fibre has been treated as opposed to the untreated areas. Acilan Direct Blue A, having the lowest molecular weight of all the dyestuffs tested, will find it easiest to diffuse through the intercellular material. Hence, it would be expected to produce the smallest colour difference, and this proved to be the case.

The reactive dyes differ from all the other dyes in that they bind covalently to the textile fibres. The fundamental problem of reactive dyeing is that the reaction of the reactive dye with water (hydrolysis) competes with the formation of the desired covalent bond between the dye and the textile substrate (fixation reaction). Therefore, for the most efficient application of reactive dyes, dyeing conditions must be chosen so that good exhaustion of the dye on to the substrate is assured before hydrolysis in the dyebath takes place.

In reactive dyeing, one of the reaction partners is present in the fibre (i.e. the sites at which adsorption and reaction occur). The other partner (i.e. the reactive dye), must first be transported to the interior of the fibre. This transportation primarily depends upon four processes: the diffusion in the dyebath to the fibre surface, the diffusion through the fibre surface and within the fibre, the adsorption and the chemical reaction. The overall effect of these four steps determines the levelness of the dyeing and the relative rates of fixation and hydrolysis.

The longer it takes for the dye to move from the dyebath to the interior of the fibre, the greater is the possibility of hydrolysis. As the level of hydrolysis increases, the level of fixation decreases, resulting in dyes which

-112- Chapter Four Results & Discussion

are not as fast. For example, reactive dyes which are fully hydrolysed before application would dye just like acid dyes, and no covalent bonds would be formed. It is the presence of the covalent bonds which largely determines the fastness of the dye. Hydrolysed dye is present within the fibre in a form where its wet fastness is governed only by physical factors, and desorption of the dye readily occurs. Once the dye is covalently bound to the substrate it is fixed. Hydrolysed dye on the other hand has a greater ability to move around within the fibre.

Dichlorotriazinyl dyes are typical of reactive dyes which hydrolyse in water. Even at maximum fixation, only about 70% of the total dye absorbed is fixed to the fibre, whereas about 30% remains in the hydrolysed form. In comparison, acrylamido dyes appear to resist hydrolysis and achieve very high levels of fixation, irrespective of the dyebath conditions. Chloro pyrimidyl dyes also demonstrate exceptional resistance to hydrolysis in the pH region 5-7, resulting in a very high degree of dye-fibre covalent bonding and hence very good wet-fastness properties of the dyeings. This high level of resistance to hydrolysis of chloropyrimidyl dyes may be explained by the inability of the pyrimidine ring system to absorb a proton under acid dyeing conditions.

The three reactive groups outlined above were the three that were used in this work. Of the three, the greatest colour difference between the treated and untreated wool was achieved with the monochlorotriazinyl reactive dye; Procion Navy HE-R. It just so happens that this particular reactive group is the least reactive of the three. It is not normally suitable for dyeing wool because it often results in unlevel dyeings. However, this proved to be of no concern as very level dyeings were achieved on all the plasma treated wool samples.

-113- Chapter Four Results & Discussion

Dyes: Untreated: Treated: 1.0% Concentrations A B C A B C

Acilan Direct Blue A 3-4 4 4 4 4 4

Carbo/an Blue BS 4 4-5 5 4-5 4-5 5

Neolan Blue 2G 3 4 4 4 4-5 4-5 lrgalan Grey BL 4-5 5 5 4 4-5 4-5

Acidol Dark Blue MTR 3-4 4 4 4 4 5

Lanasol Blue 3G 5 5 5 5 5 5

Drimalan Blue F-2GL 4-5 5 5 5 5 5

Procion Navy HE-R 4-5 5 5 5 5 5

Table 4.8. Wash Fastness Ratings for Both Untreated and Ten Minute Oxygen Plasma Treated Wool Samples

A = Change in Shade, B = Staining of Wool, and C = Staining of Cotton Chapter Four Results & Discussion

The oxidation that occurred on the surface of the modified wool greatly enhanced the diffusion of the chlorotriazinyl dye into the fibre interior.

Once inside the fibre, the reactive dye quickly anchored itself covalently to the available sites. Due to the rapid fixation, the percentage of hydrolysed dye was kept to a minimum. When the untreated wool was dyed in competition with the plasma treated wool, the dye molecules within the dyebath moved towards the dye sites that were most easily accessible. As stated above, this was where the wool had been modified. Consequently, the rate of dye-fibre fixation for modified wool was much greater than for the unmodified wool, resulting in a considerable difference in shade.

The final consideration was the effect of plasma modification on the fastness properties of the wool. Both wash fastness and light fastness were examined, and all the samples that were tested had been dyed with a dye concentration of 1.0% o.w.f. The treated samples had been modified using an oxygen plasma for ten minutes. Table 4.8. outlines the results achieved for wash fastness, rating the samples from 1 to 5 (The figure "1" represents the lowest level of fastness to washing whereas a "5" is indicative of the highest).

The modified samples exhibited very little deviation from the untreated samples, and in almost every case where a deviation did occur, it resulted in an improvement in fastness. As expected, the reactive dyes all produced very high levels of fastness to washing, due largely to the existence of covalent bonds between the dye and the fibre. Very slight improvements were evidenced for both Drimalan Blue F-2GL and Procion Navy HE-R. This could be explained by an increase in the number of covalent bonds and

-114- Chapter Four Results & Discussion

0.9

0.8 -

0.7

0.6 t \+ I -~ ~ 0 0.5 --Q,j..... Q --+--0 Min ~ 0.4 ---5Min ----....-10 Min -*-20Min 0.3 +

0.2 ,.

I 0.1 t -t i t r T I

O· 0 15 30 45 60 75 90 105 120 Time (minutes)

Figure 4.20. Rate of Dye Uptake for Wool Samples Exposed to an Oxygen Plasma for Different Periods of Time - 1.0% Procion Na vy HE-R Chapter Four Results & Discussion

Dyes: Untreated: Treated:

Acilan Direct Blue A 5-6 5-6

Carbo/an Blue BS 5-6 6

Neolan Blue 2G 5-6 5-6

Irgalan Grey BL 6-7 6

Acidol Dark Blue MTR 6-7 6-7

Lanasol Blue 3G 6 6

Drimalan Blue F-2GL 6 6

Procion Navy HE-R 5 5-6

Table 4.9. Light Fastness Ratings for Both Untreated and Ten Minute Oxygen Plasma Treated Wool Samples Chapter Four Results & Discussion

consequent decrease in hydrolysed dye as a result of a higher rate of dye uptake and fixation.

The results obtained for the light fastness test also showed very little deviation from the untreated samples. In fact, the majority of the samples remained unchanged. These results can be seen in Table 4.9. Both of these fastness results show quite clearly that wash fastness and light fastness are not diminished as a result of oxygen plasma modification of the wool.

4.4.2. Effect of Different Exposure Times

Having considered the effects of different dyestuffs, it is now appropriate to consider what effect the time of plasma exposure has on the rate of dye uptake, depth of colour, colour difference, and fastness properties.

Procion Navy HE-R was the dye used for this test as it demonstrated the most significant colour difference in Section 4.4.1. Four samples were used to examine the rate of dye uptake, and they were all dyed with a 1.0% o.w.f. dye concentration. The treatment times for the four samples examined were: untreated, 5, 10, and 20 minutes. The method used for determining the rate of dye uptake was the same as that outlined in Section 3.12.1. Figure 4.20. graphically illustrates the rate of dye uptake for the four samples.

As expected from the results obtained in the earlier work, the rate of dye uptake was higher for the plasma treated wool samples compared to that of the untreated sample. Not surprisingly, the rate of dye uptake increased as the exposure time increased. Also, the total percentage of dyestuff

-115-

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,- ·- 8 8 Chapter Four Results & Discussion

1.0% Procion Navy HE-R

Treatment Time LiE

0 Minutes 0 1 Minute 4.5 2 Minutes 7.9 3 Minutes 10.0 4 Minutes 11.2 5 Minutes 12.2 6 Minutes 12.5 8 Minutes 12.9 10 Minutes 13.3 12 Minutes 13.9 14 Minutes 14.2 16 Minutes 14.6 18 Minutes 14.5 20 Minutes 14.4

Table 4.10. Colour Difference (LiE) Between Untreated and Treated Wool Samples for Differing Periods of Treatment Time - Treatment: Exposure to an Oxygen Plasma and Dyed with a 1.0% Dye Concentration Chapter Four Results & Discussion exhausted from the dyebath increased with increase in modification time. The graph highlights the fact that modification continues to occur when the treatment time is extended, however, a significant modification occurs even after very short plasma exposure times.

Fourteen samples were used to assess the effects of different exposure times on the depth of colour, colour difference, and fastness properties. The samples used were modified with an oxygen plasma, using Template 1. All samples were then dyed simultaneously, in separate dyebaths, with each dyebath having the same dye concentration (1.0% Procion Navy HE-R) and dyeing assistants.

The L *a*b* values are given m Appendix 4.8. The ~E values are summarised in Table 4.10., and have been presented graphically in Figure 4.21. Several conclusions can be drawn by from this data. Firstly, the colour parameter L * is the most noticeably affected by the plasma modification. This too is not surprising as it is symbolic of the samples depth of shade. The larger the number, the lighter the colour, and vice versa. As can be seen from the data in the Appendix, the L * values for the modified samples decrease as the length of treatment time increases. This result indicates that the longer the period of plasma treatment, the more favorable dye fixation becomes. Visual examination of the wool samples showed quite clearly the increasing depth of shade for the modified samples.

Secondly, the L * values for the unmodified section of the sample increased as the length of treatment time increased. This suggests that less dye was able to fix in these areas. Logic seems to support this finding for the following reason. Both parts of the sample (treated and untreated) are competing for a finite number of dye molecules in the dyebath. As the

-116- Chapter Four Results & Discussion

Treatment Wash Fastness Light Fastness Time A B C

0 Minutes 4-5 5 5 5

5 Minutes 5 5 5 5

10 Minutes 5 5 5 5-6

15 Minutes 5 5 5 5-6

20 Minutes 5 5 5 5-6

Table 4.11. Wash Fastness and Light Fastness Ratings for Oxygen Plasma Treated Wool Dyed with 1.0% Procion Navy HE-R

A = Change in Shade, B = Staining of Wool, and C = Staining of Cotton Chapter Four Results & Discussion modified sample becomes increasingly favorable for dye fixation, the number of these molecules fixing in this area will increase. As a consequence, the number of available dye molecules for fixation in the untreated area decreases, resulting in a reduced depth of shade.

Thirdly, both the ~E values and the L * values changed considerably after the first five minutes of modification, however, for treatment times greater than five minutes, the change was significantly reduced. Figure 4.21. shows this finding. This result suggests that extended treatment times will not continue to increase the colour difference. The L * values for both the treated and untreated parts of the wool sample also leveled off, indicating that the modification had produced a maximum depth of shade. It is possible to conclude from this finding that significantly extended treatment times would not increase the depth of shade.

The five samples that were used to measure the rate of dye uptake were used to assess the fastness properties. The results from these tests are presented in Table 4.11. It is possible to conclude from the results that both the washfastness and lightfastness properties of the modified samples are in no way reduced because of oxygen plasma modification. However, where the results do deviate from the untreated sample, an improvement is observed.

4.4.3. Effect of Different Exposure Areas

This test was designed to examine whether the ratio of treated to untreated sample had any effect on the rate of dye uptake, depth of colour, and colour difference. Since the results so far indicate that the fastness properties of

-117- Chapter Four Results & Discussion

0.6 c...: -. -+--0% ~. -----25% 0 --50% -~ ..... --75% ~ ~100% ~ 0.4

0 5 10 15 30 45 60 75 90 120 Dyeing Time (minutes)

Figure 4.22. Rate of Dye Uptake for Samples with Different Ratios of Treated: Untreated - Samples Exposed to an Oxygen Plasma for 10 Minutes and Dyed with 1.0% Procion Navy HE-R Chapter Four Results & Discussion oxygen plasma modified wool samples are largely unaffected by the modification process, they will not be considered in this section.

Before considering the results for this test, it is important to clarify the ratios that were used. Each sample that was tested had two sides, of which only one side was exposed to the plasma. Consequently, the actual ratio of treated:untreated is different when both sides are considered. For ease of discussion, the samples have been referred to by the percentage of modification on the surface exposed to the plasma. i.e. 0% refers to the sample that was not exposed to the plasma at all, whereas 100% indicates that the sample was completely modified on one side. The other three percentages that were considered in this section were 25%, 50% and 75% surface modification. All the samples were exposed to an oxygen plasma for 10 minutes and then dyed with Procion Navy HE-R.

Two dye concentrations were used: 0.2% and 1.0% o.w.f. The rate of dye uptake, however, was considered only for the samples dyed at a dye concentration of 1.0%, and the results are given in Figure 4.22. The results indicate that the larger the area of modification the higher the rate of dye uptake. From earlier results, it was observed that plasma modification enhanced the rate of dye uptake, so that an increase in the area of modification would make dye fixation more favorable, and hence higher. Also, the larger the modified area, the greater the extent of dye exhaustion.

Appendix 4.9. outlines the Lab values for the various samples. The L * parameter is of most interest, as it indicates what is happening to the samples' depth of shade. The results clearly show that as the modified area increases, the depth of shade increases. (i.e. L * values decrease.) Also, the L * values increase for the unmodified area of the sample.

-118- Chapter Four Results & Discussion

25% 50% 75% Exposed Exposed Exposed

dE 0.2% 10.47 11.54 12.83

dE 1.0% 11.89 13.01 14.27

Table 4.12. Colour Difference Values for Different Ratios of Treated to Untreated Sample Size

16

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=Q,) .. 8 ...~ 00.20% Q -t-- .. 6 . 1.00% .£= 4 u0 ' 2

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Figure 4.23. Effect of Different Plasma Modified Areas on the Colour Difference Chapter Four Results & Discussion

Table 4.12. lists the colour difference values between the treated and untreated areas of the sample. These results are also graphically depicted in Figure 4.23. In every instance, the colour difference was greater for the 1.0% samples than for the 0.2% samples. More importantly, the trend that is highlighted by the graph is that the colour difference increases as the degree of surface modification increases.

The results obtained for the various tests highlight that the oxygen plasma modification of wool enhances the rate of dye uptake considerably, and also increases the depth of colour. Both of these factors are influenced by the dyestuff used, the extent of plasma modification, and the area of wool modified. The modified samples consistently produced level-dyeings despite a quicker fixation rate. From an environmental perspective, the modification offers considerable advantages in that the dye and auxiliary requirements are reduced and hence, so too, is the level of contamination of the effluent that is discharged.

All the dyes examined in this work showed an improvement in the rate of dye uptake, however, for some dyes, this rate of dye uptake was doubled, resulting in dyeing times being halved. This higher rate of dye uptake satisfies the quick-response requirement, and offers the potential for increasing the productivity of the plant.

Colouration effects are also possible as a result of plasma modification. When modified and unmodified wool are dyed in competition with each other, a distinctive colour difference occurs due to the differing rates of dye uptake of the respective areas of the wool. The results from this work indicated that the length of plasma treatment time and the ratio of modified: unmodified wool can influence the extent of this colour difference.

-119- Chapter Five

CONCLUSIONS

5.1. Conclusions

The aim of this project was to develop new and improved methods for applying colour and patterned effects to wool, very quickly. This objective was achieved by using two very different approaches. The first approach involved the modification of the wool bulk with reactive hydrophobes, thus enabling colouration with disperse dyes, and hence transfer printing to be utilised. The second approach involved a surface modification of the wool which was achieved using an oxygen plasma treatment.

The utilisation of transfer printing as a means of applying colour to wool, unquestionably satisfies the aim of achieving quick-response. This technology enables colour to be applied in a matter of seconds, provided that the fabric has been pre-treated with the reactive hydrophobe. The process of applying the hydrophobe is still time-consuming however, being an independent stage to the application of colour, means that the fabric can be treated and stored until such time as it is required. When the customer requires the fabric, the colour can be quickly applied.

-120- Chapter Five Conclusions

It can be readily deduced from the results in Chapter Four, that the increase in the hydrophobic character of the wool depends on the following; the hydrophobic character of the hydrophobe itself, and the absolute amount of hydrophobe fixed to the wool. The greater the hydrophobic character of the amine, the lower the number of moles that will be grafted onto the wool. The data provided in the figures and tables illustrate the outstanding improvements in colour yield, dry-cleaning fastness and light fastness that have been achieved on the wool samples modified with reactive hydrophobes AB (2-Bromopropenanilide) and AP (N-2,4-Difluoro-5- Chloro-pyrimidyl Aniline). The samples that were modified with MAP (N- 2,4-Difluoro-5-Chloropyrimidyl p-Toluidine) and NNB (N-l-Naphthyl-2- Bromopropenamide) also showed signs of improvement, but to a lesser extent.

The modification of the wool surface by use of oxygen plasma, also satisfies the aim of achieving quick-response, because it produces a higher rate of dye uptake. In fact, the results in Chapter Four showed that with some dyes, the rate of dye uptake was increased by as much as 100%, effectively cutting the dyeing time in half. The wool modification also resulted in a greater depth of colour, which enabled patterned effects to be achieved when the sample was dyed in competition with non-plasma modified wool.

The rate of dye uptake, and the depth of colour achieved, varied between different dye classes. The best results were produced with the reactive dyestuff Procion Navy HE-R, and it was subsequently used to demonstrate that the plasma exposure time affected both the rate of dye uptake and the depth of colour. When treated and untreated wool was dyed in competition with each other, the ratio of the two areas also influenced the two abovementioned factors. The greater the area of exposure, the higher the rate of dye uptake, and greater the depth of colour.

-121- Chapter Five Conclusions

The two methods outlined above produced results which confirmed their suitability for achieving quick-response. However, it is important to note that these results were obtained on a laboratory scale, and three important considerations need to be addressed before industrial applications can hope to succeed. (i) Are the methods commercially feasible? (ii) Are they economically viable? (iii) What effects will they have on the environment? i) Commercial feasibility: The two stages involved in the transfer printing method are: the application of the hydrophobe from a dyebath, followed by the application of colour from transfer printing paper. Both exhaust dyeing and transfer printing are presently used on an industrial scale. This effectively means that no new machines are required to adopt this technology. Only the reactive hydrophobes will have to be synthesised on an industrial scale before commercial applications can occur.

Two stages are also involved in the application of colour to plasma modified wool. Firstly, the wool has to be modified. Wool is presently modified by oxygen plasma on an industrial scale, in order to reduce it's tendency to shrink. The same technology can be utilised to enhance the rate of dye uptake. The second stage involves the application of colour, and once again this was achieved via exhaust dyeing. For patterned effects to be achieved, plasma machines will have to be modified. Industrial sized templates will need to be incorporated into the machine design. ii) Economic viability: In solving the problem of quick-response, another problem may have arisen; is it economically viable? The actual cost involved in utilising these two technologies is of prime importance, and

-122- Chapter Five Conclusions

special consideration is required. Previously, the application of colour to wool required a single process. Now, as a result of the wool modification, an additional processing stage has been created. There is little doubt that this adds to the cost of processing. The cost of the reactive hydrophobe itself is an unknown factor, as those outlined in this work are presently not available for commercial use. Its cost will most certainly influence the economic viability of the process.

There are, however, economic benefits as a result of each process. Transfer printing, when compared to conventional printing, requires significantly less floor space, and a fraction of the capital investment. Less labour is required to run the transfer calender, and significant energy savings are achieved. Dyeing of plasma treated wool also offers significant cost savings. These savings are primarily brought about by a reduction in dyestuff and chemical usage and, as a consequence, the cost of treating textile effluent is proportionally reduced. Further cost savings are achieved due to a reduction in dyeing times, and the production capabilities of the plant are increased accordingly. iii) Environmental Impacts: Over the past decade, public awareness of the industry's impact on the environment has significantly increased. Along with this increased awareness has come new government legislation which has necessitated that industry clean up its act. Consequently, the environmental impact of the two quick-response methods outlined in this work is an essential consideration if this is to be a viable technology in years to come.

The application of the reactive hydrophobes from the dyebath to the wool is a colourless process. The resultant effluent that is discharged is therefore

-123- Chapter Five Conclusions absent of any dyestuff and hence colourless. This reduces the treatment required to recycle the wastewater. Also, at no stage during the transfer printing process are toxic fumes produced. Therefore, no measurable air pollution is released into the atmosphere.

In the case of plasma treated wool, the modification is a dry process. Therefore, significant energy and water savings are realised. The plasma treatment process itself causes no environmental pollution. When the plasma treated wool is dyed, greater dye exhaustion occurs and at a higher rate than for untreated wool. The direct result of this is a reduction in the amount of dyestuff present in the effluent. Additionally, the wool modification resulted in dyeings which were extremely level, even for reactive dyestuffs. The amount of levelling agent used was subsequently reduced, lowering the chemical load of the effluent.

It is appropriate to consider the scope that exists for further study. Firstly, both the technologies researched in this work required an additional processing step. There is scope for research that devises a technology that does not include this extra step. Secondly, time did not permit for an examination of hydrophobe modified wool after it had been stored for a significant period of time. It would be desirable to examine whether degradation of the modified wool occurs as a result of prolonged storage. Finally, oxygen was the only gas used for plasma modification in this work. Other gases may further increase the rate of dye uptake, and therefore should be examined in a similar manner. Also, the effects of altering the chemical composition of the dyebath and the dyeing procedure should also be considered.

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166. Zollinger, H., Influence of Fibre Morphology and Swelling Water on the Diffusion of Dyes in Wool, Melliand Textilberichte, English Edition, 9 (1987) E294.

167. Koga, J., Joko, K. and Kuroki, N., Proceedings 7th International Wool Textile Research Conference, Tokyo, 1985 (V) P.14.

168. Lewis, D.M., and Pailthorpe, M.T., Evaluation of a Series of Reactive Ionic, Nonionic, and Hydrophobic Compounds as Antistatic Agents for Wool, Textile Research Journal, Vol.54, No.5, May 1984, P.279.

169. Wang, C.G., Hydrophobic Wool, Ph.D. Thesis, University of New South Wales, 1990, P.47.

170. Peirce, F.T., The "Handle" of Cloth as a Measurable Quantity, The Journal of The Textile Institute, Volume 21, 1930, P.377.

-144- Appendix 2.1.

Table A.2.1. IOR Values of Substituents

Substituent Inorganic Substituent Inorganic Value Value Light Metal 500 Lactone 120 Heavy Metal 400 -C0-0-CO- 110 -AsOJlli 300 Anthracene 105 -AsOiH 300 Phenanthrene 105 -S02-NH-CO- 260 -OH 100

-N=N-Nlli 260 >Hg 95

=N-OH 250 -NH-NH- 80 -SOJH 250 -O-C0-0- 80 -NH-S02-NH- 250 -N< 70

-CO-NH-CO-NH-CO- 250 >CO 65 =SOH 240 -COOR 60 -CO-NH-CO-NH- 240 Naphthalene 60 -S02-NH- 240 Quinoline 60 -CS-NH- 230 >C=NH 50 -CO-NH-CO- 230 -N=N- 30 =N-OH 220 -0- 20 -NH-CO-NH- 220 Benzene 15 =N-NH- 210 Nucleus 10 -CO-NH-NH- 210 Triple Bond 3 -CO-NH- 200 Double Bond 2 -COOH 150 Single Bond 1

-145- Appendix 2.1.

·>· < Substituent Orgamc morganic Value Value

R4BiOH 80 250

R4SbOH 60 250

R4As0H 40 250

R4POH 20 250

>S02 40 110

-CSSH 120 80

-S-CN 90 80

-CSOH 80 80

-COSH 80 80

-NCS 70 75

-N02 80 70

-Bi< 60 70

-Sb< 60 70

-As< 40 70

-CN 40 70

-P< 20 70

-CSSR 130 50

-146- Appendix 2.1.

Sttbstituent Organic Inorganic Value Value

-CSOR 80 50 -COSR 80 50 -NO 50 50 -O-NO2 60 40 -NC 40 40 -Sb=Sb- 90 30 -As=As- 60 30

-P=P- 30 30 -NCO 30 30 -O-NO 40 25 -SH 40 25 >S 40 25 =S 50 10

-I 80 10

-Br 60 10 -Cl 40 10

-F 5 5 Iso>- -10 0 Tert. >- -20 0

-147- Appendix 3.1.

Name: Structure: Grade: Made By:

Aniline Ar - Nlh Analytical AJAX

p - Toluidine Clli - AR - Nlh 99.9% Assay ALD

1-Naphthylamine n - C10H, - Nlh 99% Assay EGA

Table A.3.1.A. The Amines Employed to Form Hydrophobic Components

Name: Type: Made By:

Anionic dispersing agent of the Matexil DA-AC Naphthalene Sulphonic Acid - ICI Formaldehyde condensate type.

Non-ionic dispersing agent of Fatty Teric PE 68 Alcohol Poly (Ethylene Glycol) type. ICI

Table A.3.1.B. The Reagents Employed to Disperse the Reactive Hydrophobes in Water

-148- Appendix 3.2.

Chemical Structures for Dyes Used in this Work

Dyes Used for Transfer Printing:

o-@ Bafixan Red BF

0 OH

Bafixan Pink FF3B 0 0

0 NH2

Bafixan Turquoise G Structure Not Available

-149- Appendix 3.2.

Dyes Used for Plasma Modification:

Acilan Direct Blue A

NH2

Carbolan Blue BS 0 0 NH--©-C,,H3 SO,Na

Neolan Blue 2G 0 N=N 00 0

CrComplex

-150- Appendix 3.2.

0 0 \ I lrgalan Grey BL o-cr-o"'-_ I \ 0 N I

NH \

0 Na03S

N- N= Acidol Dark Blue MTR o,\ / o 0 / Cr '-. 0 \ Na03S 0 = N-N 0 0 0

-151- Appendix 3.2.

Drimalan Blue F-2GL 0-NH

F

Lanasol Blue 3G 0-NH- C0- 1=CH2 Br

Procion Navy HE-R

NH-R

-152- Appendix 3.3.

Each particular dye class has a specific recipe for application. This has been determined in each case, by the manufacturer of the dye. The dyeing methods which are outlined below, are those recommended by the manufacturer, and when followed, should result in the optimum dyeing conditions.

3.3.1. Acilan Direct Blue A

100 80 (OC) 60 40 20 0 ----+-+------+-----1------1--+------I 0 20 40 60 80 100 120 Time (minutes)

METHOD: - The acidity of the dyebath is adjusted to pH 2-3 with an addition of 3% Sulphuric Acid (96%), followed by an addition of 10% Glauber's Salt. - After running for a short time at 50°C, the thoroughly dissolved dyestuff is added. - After a short run, the dyebath is brought to the boil in about 30 minutes, and dyeing is completed at boiling temperature. - Depending on the material, the boiling time generally amounts to between 45-90 minutes.

CALCULATIONS: - 3% Sulphuric Acid= 0.06ml - 10% Glauber's Salt= 0.175g

-153- Appendix 3.3.

3.3.2. Carbolan Blue BS

100 80 (OC) 60 .____, 40 20 0 -----1------,1-----t------l 0 20 40 60 80 100 120 Time (minutes)

METHOD: - The acidity of the dye bath is adjusted to pH 5-6 with an addition of 2% Ammonium Acetate. - After running for a short time at 50-60°C, the thoroughly dissolved dyestuff is added. - After a short run, the dyebath is brought to the boil in about 30 minutes, and dyeing is completed at boiling temperature. - The maximum absorption of the dyestuffs takes place at about 70°C and it is advisable, therefore, to raise the temperature of the dyebath slowly from 60°C up to the boil. - Prolonged boiling is not necessary, which is an advantage when dyeing fine wools.

CALCULATIONS: - 2% Ammonium Acetate = 0.04g Final exhaustion requires: - 2% Ammonium Sulphate = 0.04g

-154- Appendix 3.3.

3.3.3. Neolan Blue 2G

100 80 (OC) 60 40 20 0 +---+--+---+--+-----t--+---tt---+---tt---+--t----t 0 20 40 60 80 100 120 Time (minutes)

METHOD: - The acidity of the dyebath is adjusted to pH 2.5-2.8 with the addition of 4% Sulphuric Acid (96%) and 1 %Albegal FF A. - After running for a short time at 60°C, the thoroughly dissolved dyestuff is added. - After a short run, the dyebath is brought to the boil in about 30 minutes, and dyeing is completed at boiling temperature. - Depending on the material, the boiling time generally amounts to between 45-90 minutes. - The quality of the goods will benefit still further - particularly on prolonged dyeing - from an addition of 1-2g/L Irgasol HTW.

CALCULATIONS: - 4% Sulphuric Acid = 0.07ml - 1 % Albegal FF A = 0.02ml

-155- Appendix 3.3.

3.3.4. Irgalan Grey BL

100 80 60 (OC) 40 ---- 20 0 +---+--+---+----+-+---t--+---+----t---+--t-----1 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (minutes)

METHOD: - The pH of the dyebath is adjusted to 5-6 with the use of 1% Acetic Acid, 0.7% Albegal A and 10% Glauber's Salt. - After running for a short time at 50°C, the thoroughly dissolved dyestuff is added. - After a short run, the dyebath is brought to the boil over 30 minutes, and dyeing is completed at boiling temperature.

CALCULATIONS: - 1 % Acetic Acid= 0.02ml - 0.7% Albegal A= 0.015ml - 10% Glauber's Salt = 0.175g

-156- Appendix 3.3.

3.3.5. Acidol Dark Blue M-TR

100 80 60 (OC) 40 20

0 0------10 20 30 40 50 60 70 80 90 100 110120 Time (minutes)

METHOD: - The pH of the dyebath is adjusted to 5-6 with the use of 1 % Uniperol W and 5% Ammonium Sulphate. - The dye bath is heated from 40-50°C over 10 minutes, and then the thoroughly dissolved dyestuff is added. - After a short run, the dyebath is brought to the boil in about 45 minutes, and dyeing is then completed at this temperature for the next 30-60 minutes, depending on the depth of shade.

CALCULATIONS: - 1 % Uniperol W = 0.02g - 5% Ammonium Sulphate= 0.lg

-157- Appendix 3.3.

3.3.6. Drimalan Blue F-2GL

100 80 60 (OC) 40 20 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (minutes)

METHOD: - The pH of the dyebath is adjusted to 5-6 with the use of 10% Glauber's Salt, 4% Ammonium Sulphate and 1 % Acetic Acid (80%). - The chemicals are added in solution to the bath at 40°C. To prevent surface foaming, the Drimagen F should not be added until the bath has been completely made up. The goods are run in the bath containing the chemicals for 10 minutes, then the well dissolved dyestuff is added. - In 20 minutes, the bath is raised to 65°C and dyeing is continued at this temperature for 30 minutes. The temperature is then increased to 100°C in 30 minutes and the dyeing fixed at this temperature for 20 minutes. - These times must be strictly observed - even if the dyebath is completely exhausted - to ensure the chemical fixation of the dyestuff, so that the maximum wet fastness properties are attained.

CALCULATIONS: - 10% Glauber's Salt= 0.175g - 4% Ammonium Sulphate= 0.07g - 1 % Acetic Acid (80%) = 0.02ml

-158- Appendix 3.3.

3.3.7. Lanasol Blue 3G

100 80 60 (OC) 40 20 0 -+----1------t------t 0 20 40 55 70 90 110 Time (minutes)

METHOD: -To ensure rapid removal of air and wetting out of the goods, 0.4 g/1 Albegal FF A should be added first to the bath. This addition should occur when the bath temperature is 50°C. - The pH of the dyebath is adjusted to 6.5-7.0 with the use of 10% Glauber's Salt, 4% Ammonium Sulphate and 1 % Acetic Acid (80%). - The goods are run in the bath containing the chemicals for 10 minutes, then the well dissolved dyestuff is added. - Over 20 minutes, the bath is raised to 70°C and dyeing is continued at this temperature for 15 minutes. The temperature is then increased to 98°C over 20 minutes, and the dye is fixed at this temperature for a further 30 minutes.

CALCULATIONS: -10% Glauber's Salt= 0.175g - 4% Ammonium Sulphate = 0.07ml - 1 % Acetic Acid (80%) = 0.02ml

-159- Appendix 3.3.

3.3.8. Procion Navy HE-R

100 80

60 -1----- (0C) 40 20 0 +---+--+--+----+--+---t,---+--+------t----t-~t-----1 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (minutes)

METHOD: - The pH of the dyebath is adjusted to 4.5-5.0 with the use of 1 % Acetic Acid (80%), and 10% Glauber's Salt. Initially, the temperature of the bath is 60°C. - 0.4g/l Albegal FF A is added to the dyebath, to ensure that the goods are thoroughly wet out. - The goods are then added to the bath containing the chemicals and run for a period of ten minutes. The dissolved dyestuff is then added. - The temperature of the dyebath is then raised to 80°C over 20 minutes and held at this temperature for 30 minutes. The temperature is then increased to 100°C over 20 minutes, and is maintained at this temperature for a further 30 minutes.

CALCULATIONS: - 1 % Acetic Acid (80%) = 0.02ml - 10% Glauber's Salt= 0.175g - 0.4g/l Albegal FF A = 0.04g

-160- Appendix 4.1.

Table A.4.1.A. Reactive Hydrophobe AP

Sample Sample Ori~ Final Difference % Code Cone. Weight Weight Difference AlR 5 1.9068g 1.9813g 0.0745g 3.9% AlP 5 1.9620g 2.0346g 0.0726g 3.7% AlT 5 1.9476g 2.0218g 0.0742g 3.8% A2R 5 1.9625g 2.0397g 0.0772g 3.9% A2P 5 1.9029g 1.9749g 0.0720g 3.8% A2T 5 1.9007g 1.9701g 0.0694g 3.7% AlR 10 1.8968g 2.0105g 0.1137g 6.0% AlP 10 1.8962g 2.0089g 0.1127g 5.9% AlT 10 1.9159g 2.0324g 0.1165g 6.1% A2R 10 1.9068g 2.0219g 0.1151g 6.0% A2P 10 1.9375g 2.0540g 0.1165g 6.0% A2T 10 1.9510g 2.0659g 0.1149g 5.9% AlR 15 1.8967g 2.0346g 0.1379g 7.3% AlP 15 1.9242g 2.0601g 0.1359g 7.1% AlT 15 1.9344g 2.0703g 0.1359g 7.0% A2R 15 1.9967g 2.1399g 0.1432g 7.2% A2P 15 1.9535g 2.0898g 0.1363g 7.0% A2T 15 1.9428g 2.0805g 0.1377g 7.1% AlR 20 1.9104g 2.0557g 0.1453g 7.6% AlP 20 1.9226g 2.0662g 0.1436g 7.5% AlT 20 1.9123g 2.0564g 0.1441g 7.5% A2R 20 1.9291g 2.0783g 0.1492g 7.7% A2P 20 1.9183g 2.0659g 0.1476g 7.7% A2T 20 1.9161g 2.0610g 0.1449g 7.6% AlR 25 1.8777g 2.0227g 0.1450g 7.7% AlP 25 1.9395g 2.0888g 0.1493g 7.7% AlT 25 1.8994g 2.0473g 0.1479g 7.8% A2R 25 1.9185g 2.0660g 0.1475g 7.7% A2P 25 1.9075g 2.0537g 0.1462g 7.7% A2T 25 1.9120g 2.0598g 0.1478g 7.7%

-161- Appendix 4.1.

Table A.4.1.B. Reactive Hydrophobe AB

Sample Sample Ori~! Final Difference % Code Cone. Weight Weight Difference CIR 5 1.9349g 1.9986g 0.0637g 3.3% ClP 5 1.9230g 1.9845g 0.0615g 3.2% CIT 5 1.9395g 1.9973g 0.0578g 3.0% C2R 5 1.9382g 1.9969g 0.0587g 3.0% C2P 5 1.9189g 1.9782g 0.0593g 3.1 % C2T 5 1.9068g 1.9667g 0.0599g 3.1 % CIR 10 1.9407g 2.0356g 0.0949g 4.9% ClP 10 1.9379g 2.0298g 0.0919g 4.7% CIT 10 1.9138g 2.0062g 0.0924g 4.8% C2R 10 1.9103g 2.0043g 0.0939g 4.9% C2P 10 1.9099g 2.0018g 0.0919g 4.8% C2T 10 1.9146g 2.0040g 0.0894g 4.7% CIR 15 1.9494g 2.0660g 0.1166g 6.0% ClP 15 1.9011g 2.0135g 0.1124g 5.9% CIT 15 1.9449g 2.0630g 0.1181g 6.1% C2R 15 1.9289g 2.0468g 0.1179g 6.1% C2P 15 1.9341g 2.0507g 0.1166g 6.0% C2T 15 1.9239g 2.0405g 0.1166g 6.1% CIR 20 1.9815g 2.1160g 0.1345g 6.8% ClP 20 1.9284g 2.0607g 0.1323g 6.9% CIT 20 1.9524g 2.0887g 0.1363g 7.0% C2R 20 1.9471g 2.0818g 0.1347g 6.9% C2P 20 1.9208g 2.0558g 0.1350g 7.0% C2T 20 1.9119g 2.0436g 0.1317g 6.9% CIR 25 1.9092g 2.0486g 0.1394g 7.3% ClP 25 1.9266g 2.0703g 0.1437g 7.6% CIT 25 1.9262g 2.0687g 0.1425g 7.4% C2R 25 1.9341g 2.0757g 0.1416g 7.3% C2P 25 1.9095g 2.0535g 0.1440g 7.5% C2T 25 1.9111g 2.0550g 0.1439g 7.5%

-162- Appendix 4.1.

Table A.4.1.C. Reactive Hydrophobe MAP

Sample Sample Ori~ Final Difference % Code Cone. Weight Weight Difference BlR 5 1.9178g 1.9843g 0.0665g 3.5% BlP 5 1.9386g 2.0068g 0.0682g 3.5% BlT 5 1.9129g 1.9835g 0.0706g 3.7% B2R 5 1.9365g 2.0095g 0.0720g 3.7% B2P 5 1.9582g 2.0263g 0.0681g 3.5% B2T 5 1.9566g 2.0267g 0.0700g 3.6% BlR 10 1.9380g 2.0363g 0.0983g 5.1% BlP 10 1.9137g 2.0090g 0.0953g 5.0% BlT 10 1.9505g 2.0521g 0.1016g 5.2% B2R 10 1.9077g 2.0056g 0.0979g 5.1 % B2P 10 1.9223g 2.0201g 0.0978g 5.1 % B2T 10 1.9171g 2.0164g 0.0993g 5.2% BlR 15 1.9754g 2.0856g 0.1102g 5.6% BlP 15 1.9566g 2.0668g 0.1102g 5.6% BlT 15 1.9389g 2.0486g 0.1097g 5.7% B2R 15 1.9175g 2.0251g 0.1076g 5.6% B2P 15 1.8785g 1.9828g 0.1043g 5.6% B2T 15 1.9055g 2.0107g 0.1052g 5.5% BlR 20 1.9842g 2.0961g 0.1119g 5.6% BlP 20 1.9260g 2.0385g 0.1125g 5.8% BlT 20 1.8944g 2.0028g 0.1084g 5.7% B2R 20 1.9230g 2.0374g 0.1144g 6.0% B2P 20 1.9310g 2.0443g 0.1133g 5.9% B2T 20 1.9383g 2.0501g 0.1118g 5.8% BlR 25 1.9250g 2.0399g 0.1149g 6.0% BlP 25 1.9428g 2.0565g 0.1137g 5.9% BlT 25 1.9071g 2.0194g 0.1123g 5.9% B2R 25 1.9110g 2.0253g 0.1143g 6.0% B2P 25 1.9477g 2.0630g 0.1153g 5.9% B2T 25 1.9420g 2.0575g 0.1155g 6.0%

-163- Appendix 4.1.

Table A.4.1.D. Reactive Hydrophobe NNB

Sample Sample Origir!al Final Difference % Code Cone. Weight Weight Difference DlR 5 1.9608g 2.0131g 0.0523g 2.7% DlP 5 1.9756g 2.0272g 0.0516g 2.6% DlT 5 1.9382g 1.9874g 0.0492g 2.5% D2R 5 1.9557g 2.0065g 0.0508g 2.6% D2P 5 1.9511g 1.9992g 0.0481g 2.5% D2T 5 1.9139g 1.9628g 0.0489g 2.6% DlR 10 1.9177g 1.9908g 0.0731g 3.8% DlP 10 1.9146g 1.9872g 0.0726g 3.8% DlT 10 1.9086g 1.9838g 0.0752g 3.9% D2R 10 1.9011g 1.9751g 0.0740g 3.9% D2P 10 1.9149g 1.9921g 0.0772g 4.0% D2T 10 1.9339g 2.0lllg 0.0772g 4.0% DlR 15 1.9401g 2.0357g 0.0956g 4.9% DlP 15 1.9552g 2.0473g 0.0921g 4.7% DlT 15 1.9425g 2.0334g 0.0909g 4.7% D2R 15 1.9393g 2.0332g 0.0939g 4.8% D2P 15 1.9281g 2.0222g 0.0941g 4.9% D2T 15 1.9341g 2.0258g 0.0917g 4.7% DlR 20 1.9377g 2.0402g 0.1025g 5.3% DlP 20 1.9621g 2.0651g 0.1030g 5.3% DlT 20 1.9584g 2.0626g 0.1042g 5.3% D2R 20 1.9303g 2.0347g 0.1044g 5.4% D2P 20 1.9080g 2.0105g 0.1025g 5.4% D2T 20 1.9179g 2.0176g 0.0997g 5.2% DlR 25 1.9124g 2.0162g 0.1038g 5.4% DlP 25 1.9083g 2.0169g 0.1086g 5.7% DlT 25 1.9512g 2.0612g 0.1100g 5.6% D2R 25 1.9430g 2.0518g 0.1088g 5.6% D2P 25 1.9300g 2.0367g 0.1067g 5.5% D2T 25 1.9284g 2.0358g 0.1074g 5.6%

-164- Appendix 4.2.

A.4.2.A. Reactive Hydrophobe AP

AIR = 3.91 X 1.9068 X 1.09/241.6 X 100 = 0.0003363 AlP = 3.70 X 1.9620 X 1.09/241.6 X 100 = 0.0003275 AlT = 3.81 X 1.9476 X 1.09/241.6 X 100 = 0.0003347 5% A2R = 3.93 X 1.9625 X 1.09/241.6 X 100 = 0.0003479 A2P = 3.78 X 1.9029 X 1.09/241.6 X 100 = 0.0003245 A2T = 3.65 X 1.9007 X 1.09/241.6 X 100 = 0.0003129

AIR = 5.99 X 1.8968 X 1.09/241.6 X 100 = 0.0005124 AlP = 5.94 X 1.8962 X 1.09/241.6 X 100 = 0.0005079 AlT = 6.08 X 1.9159 X 1.09/241.6 X 100 = 0.0005253 10% A2R = 6.04 X 1.9068 X 1.09/241.6 X 100 = 0.0005194 A2P = 6.01 X 1.9375 X 1.09/241.6 X 100 = 0.0005251 A2T = 5.89 X 1.9510 X 1.09/241.6 X 100 = 0.0005182

AIR = 7.27 X 1.8967 X 1.09/241.6 X 100 = 0.0006218 AlP = 7.06 X 1.9242 X 1.09/241.6 X 100 = 0.0006126 AlT = 7.03 X 1.9344 X 1.09/241.6 X 100 = 0.0006133 15% A2R = 7.17 X 1.9967 X 1.09/241.6 X 100 = 0.0006456 A2P = 6.98 X 1.9535 X 1.09/241.6 X 100 = 0.0006149 A2T = 7.09 X 1.9428 X 1.09/241.6 X 100 = 0.0006212

AIR = 7.61 X 1.9104 X 1.09/241.6 X 100 = 0.0006556 AlP = 7.47 X 1.9226 X 1.09/241.6 X 100 = 0.0006477 AlT = 7.54 X 1.9123 X 1.09/241.6 X 100 = 0.0006502 20% A2R = 7.73 X 1.9291 X 1.09/241.6 X 100 = 0.0006725 A2P = 7.69 X 1.9183 X 1.09/241.6 X 100 = 0.0006653 A2T = 7.56 X 1.9161 X 1.09/241.6 X 100 = 0.0006533

AIR = 7.72 X 1.8777 X 1.09/241.6 X 100 = 0.0006537 AlP = 7.70 X 1.9395 X 1.09/241.6 X 100 = 0.0006735 AlT = 7.79 X 1.8994 X 1.09/241.6 X 100 = 0.0006673 25% A2R = 7.69 X 1.9185 X 1.09/241.6 X 100 = 0.0006653 A2P = 7.66 X 1.9075 X 1.09/241.6 X 100 = 0.0006589 A2T = 7.73 X 1.9120 X 1.09/241.6 X 100 = 0.0006665

-165- Appendix 4.2.

A.4.2.B. Reactive Hydrophobe MAP

BIR = 3.47 X 1.9178 X 1.08/255.7 X 100 = 0.0002808 BlP = 3.52 X 1.9386 X 1.08/255.7 X 100 = 0.0002879 BIT = 3.69 X 1.9129 X 1.08/255.7 X 100 = 0.0002978 5% B2R = 3.72 X 1.9365 X 1.08/255.7 X 100 = 0.0003039 B2P = 3.48 X 1.9582 X 1.08/255.7 X 100 = 0.0002875 B2T = 3.58 X 1.9566 X 1.08/255.7 X 100 = 0.0002955

BIR = 5.07 X 1.9380 X 1.08/255.7 X 100 = 0.0004146 BlP = 4.98 X 1.9137 X 1.08/255.7 X 100 = 0.0004021 BIT = 5.21 X 1.9505 X 1.08/255.7 X 100 = 0.0004288 10% B2R = 5.13 X 1.9077 X 1.08/255.7 X 100 = 0.0004129 B2P = 5.09 X 1.9223 X 1.08/255.7 X 100 = 0.0004129 B2T = 5.18 X 1.9171 X 1.08/255.7 X 100 = 0.0004190

BIR = 5.58 X 1.9754 X 1.08/255.7 X 100 = 0.0004651 BlP = 5.63 X 1.9566 X 1.08/255.7 X 100 = 0.0004648 BIT = 5.66 X 1.9389 X 1.08/255.7 X 100 = 0.0004631 15% B2R = 5.61 X 1.9175 X 1.08/255.7 X 100 = 0.0004539 B2P = 5.55 X 1.8785 X 1.08/255.7 X 100 = 0.0004399 B2T = 5.52 X 1.9055 X 1.08/255.7 X 100 = 0.0004438

BIR = 5.64 X 1.9842 X 1.08/255.7 X 100 = 0.0004722 BlP = 5.84 X 1.9260 X 1.08/255.7 X 100 = 0.0004746 BIT = 5.72 X 1.8944 X 1.08/255.7 X 100 = 0.0004572 20% B2R = 5.95 X 1.9230 X 1.08/255.7 X 100 = 0.0004828 B2P = 5.87 X 1.9310 X 1.08/255.7 X 100 = 0.0004783 B2T = 5.77 X 1.9383 X 1.08/255.7 X 100 = 0.0004719

BIR = 5.97 X 1.9250 X 1.08/255.7 X 100 = 0.0004849 BlP = 5.85 X 1.9428 X 1.08/255.7 X 100 = 0.0004796 BIT = 5.89 X 1.9071 X 1.08/255.7 X 100 = 0.0004740 25% B2R = 5.98 X 1.9110 X 1.08/255.7 X 100 = 0.0004822 B2P = 5.92 X 1.9477 X 1.08/255.7 X 100 = 0.0004865 B2T = 5.95 X 1.9420 X 1.08/255.7 X 100 = 0.0004876

-166- Appendix 4.2.

A.4.2.C. Reactive Hydrophobe AB

ClR = 3.29 X 1.9349 X 1.56/226.1 X 100 = 0.0004386 ClP = 3.20 X 1.9230 X 1.56/226.1 X 100 = 0.0004239 ClT = 2.98 X 1.9395 X 1.56/226.1 X 100 = 0.0003981 5% C2R = 3.03 X 1.9382 X 1.56/226.1 X 100 = 0.0004046 C2P = 3.09 X 1.9189 X 1.56/226.1 X 100 = 0.0004085 C2T = 3.14 X 1.9068 X 1.56/226.1 X 100 = 0.0004125

ClR = 4.89 X 1. 9407 X 1.56/226.1 X 100 = 0.0006538 ClP = 4.74 X 1.9379 X 1.56/226.1 X 100 = 0.0006328 ClT = 4.83 X 1.9138 X 1.56/226.1 X 100 = 0.0006368 10% C2R = 4.92 X 1.9103 X 1.56/226.1 X 100 = 0.0006475 C2P = 4.81 X 1.9099 X 1.56/226.1 X 100 = 0.0006329 C2T = 4.67 X 1.9146 X 1.56/226.1 X 100 = 0.0006160

ClR = 5.98 X 1.9494 X 1.56/226.1 X 100 = 0.0008031 ClP = 5.91 X 1.9011 X 1.56/226.1 X 100 = 0.0007741 ClT = 6.07 X 1.9449 X 1.56/226.1 X 100 = 0.0008134 15% C2R = 6.11 X 1.9289 X 1. 56/226 .1 X 100 = 0.0008120 C2P = 6.03 X 1.9341 X 1.56/226.1 X 100 = 0.0008035 C2T = 6.06 X 1.9239 X 1.56/226.1 X 100 = 0.0008032

ClR = 6.79 X 1.9815 X 1.56/226.1 X 100 = 0.0009270 ClP = 6.86 X 1.9284 X 1.56/226.1 X 100 = 0.0009114 ClT = 6.98 X 1.9524 X 1.56/226.1 X 100 = 0.0009389 20% C2R = 6.92 X 1.9471 X 1.56/226.1 X 100 = 0.0009283 C2P = 7.03 X 1.9208 X 1.56/226.1 X 100 = 0.0009303 C2T = 6.89 X 1.9119 X 1.56/226.1 X 100 = 0.0009076

ClR = 7.30 X 1.9092 X 1.56/226.1 X 100 = 0.0009602 ClP = 7.46 X 1.9266 X 1.56/226.1 X 100 = 0.0009902 ClT = 7.40 X 1.9262 X 1.56/226.1 X 100 = 0.0009819 25% C2R = 7.32 X 1.9341 X 1.56/226.1 X 100 = 0.0009754 C2P = 7.54 X 1.9095 X 1.56/226.1 X 100 = 0.0009919 C2T = 7.53 X 1.9111 X 1.56/226.1 X 100 = 0.0009915

-167- Appendix 4.2.

A.4.2.D. Reactive Hydrophobe NNB

DlR = 2.67 x 1.9608 x 1.41/276.1 x 100 = 0.0002670 DlP = 2.61 x 1.9756 x 1.41/276.1 x 100 = 0.0002629 DlT = 2.54 x 1.9382 x 1.41/276.1 x 100 = 0.0002510 5% D2R = 2.60 x 1.9557 x 1.41/276.1 x 100 = 0.0002593 D2P = 2.47 x 1.9511 x 1.41/276.1 x 100 = 0.0002457 D2T = 2.55 x 1.9139 x 1.41/276.1 x 100 = 0.0002489

DlR = 3.81 x 1.9177 x 1.41/276.1 x 100 = 0.0003726 DlP = 3.79 x 1.9146 x 1.41/276.1 x 100 = 0.0003700 DlT = 3.94 x 1.9086 x 1.41/276.1 x 100 = 0.0003835 10% D2R = 3.89 x 1.9011 x 1.41/276.1 x 100 = 0.0003771 D2P = 4.03 x 1.9149 x 1.41/276.1 x 100 = 0.0003935 D2T = 3.99 x 1.9339 x 1.41/276.1 x 100 = 0.0003935

DlR = 4.93 x 1.9401 x 1.41/276.1 x 100 = 0.0004877 DlP = 4.71 x 1.9552 x 1.41/276.1 x 100 = 0.0004696 DlT = 4.68 x 1.9425 x 1.41/276.1 x 100 = 0.0004636 15% D2R = 4.84 x 1.9393 x 1.41/276.1 x 100 = 0.0004786 D2P = 4.88 x 1.9281 x 1.41/276.1 x 100 = 0.0004798 D2T = 4.74 x 1.9341 x 1.41/276.1 x 100 = 0.0004675

DlR = 5.29 x 1.9377 x 1.41/276.1 x 100 = 0.0005227 DlP = 5.25 x 1.9621 x 1.41/276.1 x 100 = 0.0005253 DlT = 5.32 x 1.9584 x 1.41/276.1 x 100 = 0.0005313 20% D2R = 5.41 x 1.9303 x 1.41/276.1 x 100 = 0.0005325 D2P = 5.37 x 1.9080 x 1.41/276.1 x 100 = 0.0005225 D2T = 5.20 x 1.9179 x 1.41/276.1 x 100 = 0.0005086

DlR = 5.43 x 1.9124 x 1.41/276.1 x 100 = 0.0005296 DlP = 5.69 x 1.9083 x 1.41/276.1 x 100 = 0.0005537 DlT = 5.64 x 1.9512 x 1.41/276.1 x 100 = 0.0005612 25% D2R = 5.60 x 1.9430 x 1.41/276.1 x 100 = 0.0005549 D2P = 5.53 x 1.9300 x 1.41/276.1 x 100 = 0.0005443 D2T = 5.57 x 1.9284 x 1.41/276.1 x 100 = 0.0005478

-168- Appendix 4.3.

K/S Values for Transfer Printed Wool

Prior to Fastness Tests

Red BF Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 1.1066 2.1094 2.4136 2.4958 2.5094 2.5123 AB 1.1066 2.5938 2.8211 2.8978 2.9507 2.9538 MAP 1.1066 1.7080 1.8573 1.8913 1.8831 1.9077 NNB 1.1066 1.7487 1.9591 2.0710 2.1056 2.1023

Pi,nk FF3B Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 0.5825 1.5107 1.6983 1.7013 1.7321 1.7375 AB 0.5825 1.7472 1.8999 1.9834 2.0731 2.1029 MAP 0.5825 1.1113 1.2007 1.2189 1.2471 1.2464 NNB 0.5825 1.1631 1.4008 1.4109 1.4197 1.4218

Turquoise G Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 0.5405 1.1401 1.3590 1.4556 1.4832 1.4902 AB 0.5405 1.2813 1.4137 1.4786 1.5289 1.5375 MAP 0.5405 0.9539 0.9897 1.0015 1.0009 1.0133 NNB 0.5405 0.8718 0.9724 1.0017 1.0299 1.0594

-169- Appendix 4.4.

K/S Values for Transfer Printed Wool

After Dry-Cleaning Test

Red BF Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 0.5210 1.2693 1.6844 1.8981 1.9586 1.9837 AB 0.5210 1.4001 1.8017 2.0463 2.2915 2.4172 MAP 0.5210 0.9634 1.1182 1.1972 1.1897 1.2119 NNB 0.5210 0.9733 1.1837 1.3271 1.4199 1.4388

Pink FF3B Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 0.2434 0.8300 1.1450 1.2991 1.3750 1.3868 AB 0.2434 0.8997 1.2144 1.4697 1.6493 1.7747 MAP 0.2434 0.6702 0.8163 0.8749 0.9142 0.9135 NNB 0.2434 0.6237 0.8335 0.9879 1.0489 1.0854

Turquoise G Samples:

Percentage Hydrophobe 0 5 10 15 20 25 AP 0.1844 0.6749 0.9824 1.1310 1.1598 1.1727 AB 0.1844 0.6288 0.9103 1.0852 1.2411 1.2998 MAP 0.1844 0.5217 0.6661 0.6910 0.7057 0.7192 NNB 0.1844 0.4443 0.5619 0.6391 0.6895 0.7264

-170- ~-

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! 0.4 I -G-AB • NNB 0.2 After Drycleaning 'C> 'C 0 ~ 8 =Q. 0 1 2 3 4 5 6 7 9 ~- Weight Gain(%) !,i"" Appendix 4.6.

Acilan Direct Blue A Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 46.11 47.11 Plasma: Oxygen a* -6.79 -7.60 Treatment Time: 10 Minutes b* -35.97 -35.28 L\E 1.5

Carbo/an Blue BS Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 54.76 57.30 Plasma: Oxygen a* -13.02 -12.35 Treatment Time: 10 Minutes b* -21.36 -18.71 L\E 3.7

Neolan Blue 2G Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 44.32 46.57 Plasma: Oxygen a* -13.26 -13.08 Treatment Time: 10 Minutes b* -16.30 -15.73 L\E 2.3

Irgalan Grey BL Illuminant 0.2% Dye 0.2%Dye D65 Treated Untreated L* 50.38 55.38 Plasma: Oxygen a* -2.68 -2.80 Treatment Time: 10 Minutes b* -7.85 -6.05 L\E 5.3

-174- Appendix 4.6.

Acidol Dark Blue MTR Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 40.69 47.77 Plasma: Oxygen a* -2.03 -2.17 Treatment Time: 10 Minutes b* -14.89 -11.72 8E 7.8

Drimalan Blue F-2GL Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 59.13 61.27 Plasma: Oxygen a* -14.81 -13.51 Treatment Time: 10 Minutes b* -18.78 -15.60 8E 4.1

Lanasol Blue 3G Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 41.64 44.79 Plasma: Oxygen a* -13.04 -12.48 Treatment Time: 10 Minutes b* -28.63 -26.09 8E 4.1

Procion Navy HE-R Illuminant 0.2%Dye 0.2%Dye D65 Treated Untreated L* 30.74 41.13 Plasma: Oxygen a* 1.09 -0.32 Treatment Time: 10 Minutes b* -14.25 -9.43 8E 11.5

-175- Appendix 4.6.

Acilan Direct Blue A Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 28.72 29.66 Plasma: Oxygen a* 0.68 0.90 Treatment Time: 10 Minutes b* -41.37 -38.48 LiE 3.1

Carbo/an Blue BS Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 31.97 36.73 Plasma: Oxygen a* -6.35 -6.93 Treatment Time: 10 Minutes b* -32.89 -30.30 LiE 5.5

Neolan Blue 2G Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 29.18 32.84 Plasma: Oxygen a* -12.48 -11.80 Treatment Time: 10 Minutes b* -17.84 -17.34 LiE 3.8

Irgalan Grey BL Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 28.95 35.93 Plasma: Oxygen a* -1.83 -2.00 Treatment Time: 10 Minutes b* -9.79 -8.83 LiE 7.1

-176- Appendix 4.6.

Acidol Dark Blue MTR Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 21.34 30.57 Plasma: Oxygen a* -0.40 -1.04 Treatment Time: 10 Minutes b* -15.67 -13.87 ~E 9.4

Drimalan Blue F-2GL Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 29.69 34.18 Plasma: Oxygen a* -11.34 -11.42 Treatment Time: 10 Minutes b* -30.10 -28.42 ~E 4.8

Lanasol Blue 3G Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 25.85 29.73 Plasma: Oxygen a* -9.30 -8.81 Treatment Time: 10 Minutes b* -28.86 -27.33 ~E 4.2

Procion Navy HE-R Illuminant J.0%Dye J.0%Dye D65 Treated Untreated L* 10.28 22.22 Plasma: Oxygen a* 2.23 0.61 Treatment Time: 10 Minutes b* -12.99 -8.08 ~E 13.0

-177- Appendix 4.7.

Calculation ofMolecular Weights:

Acilan Direct Blue A

C - 20 X 12.011 = 240.2

H - 13 X 1.008 = 13.1

0 - 5 X 16.0 - 80.0

s - 1 X 32.066 - 32.1

N = 2 X 14.008 - 28.0

Na= 1 X 22.91 - 22.9

Total - 416.3

Carbolan Blue BS

C = 32 X 12.011 - 384.4

H = 37 X 1.008 - 37.3

0 - 8 X 16.0 - 128.0

s - 2 X 32.066 - 64.1

N = 2 X 14.008 - 28.0

Na= 2 X 22.91 - 45.8

Total - 687.6

-178- Appendix 4.7.

Neolan Blue 2G

C - 20X12.011 - 240.2

H - 12 X 1.008 - 12.1

0 - 8 X 16.0 - 128.0 s = 2 X 32.066 - 64.1 N = 2 X 14.008 = 28.0 Na= 2 X 22.91 = 45.8

Total - 518.3

Irgalan Grey BL

C - 40 X 12.011 - 480.4 H = 34 X 1.008 = 34.3 0 = 12 X 16.0 = 192.0 s = 2 X 32.066 - 64.1

N - 6 X 14.008 - 84.0

Cr = 1 X 52.01 - 52.0

Total - 900.9

-179- Appendix 4.8.

Treatment Time: L* a* b*

0 Minutes 18.32 0.83 -11.38

1 Minute 15.86 1.52 -11.86

2 Minutes 14.03 1.60 -12.16

3 Minutes 12.80 1.94 -12.59

4 Minutes 12.21 1.92 -12.79

5 Minutes 11.85 2.16 -12.61

6 Minutes l 1.51 2.37 -12.68

8 Minutes 10.89 2.42 -12.95

10 Minutes 10.34 2.26 -13.07

12 Minutes 9.89 2.14 -12.71

14 Minutes 9.43 2.06 -13.28

16 Minutes 9.29 2.03 -13.20

18 Minutes 9.21 2.15 -14.03

20 Minutes 9.15 1.91 -13.56

- Lab Readings for Plasma Treated Wool Samples - Dyed With 1.0% Procion Navy HE-R

-180- Appendix 4.8.

Treatment Time: L* a* b*

0 Minutes 18.32 0.83 -11.38

1 Minute 19.55 0.72 -9.45

2 Minutes 20.44 0.61 -7.61

3 Minutes 21.00 0.44 -7.01

4 Minutes 21.39 0.48 -6.47

5 Minutes 21.57 0.60 -5.49

6 Minutes 21.76 0.56 -5.78

8 Minutes 22.04 0.49 -6.67

10 Minutes 22.31 0.59 -7.47

12 Minutes 22.53 0.66 -7.19

14 Minutes 22.76 0.41 -8.61

16 Minutes 22.88 0.74 -7.94

18 Minutes 22.94 0.49 -9.64

20 Minutes 22.98 0.50 -9.84

- Lab Readings for Untreated Wool Samples - Dyed With 1.0% Procion Navy HE-R

-181- Appendix 4.9.

Percentage of Dye Illuminant Treated Sample Exposed Concentration D65 10 minutes to Plasma Oxygen Plasma L* 28.31 0.2% a* 0.65 100% b* -14.89 L* 8.45 1.0% a* 1.86 b* -14.20 L* 29.84 41.70 0.2% a* 0.87 -0.36 75% b* -14.56 -9.82 L* 9.41 22.78 1.0% a* 2.01 0.49 b* -13.68 -8.93 L* 30.74 41.13 0.2% a* 1.09 -0.32 50% b* -14.25 -9.43 L* 10.28 22.22 1.0% a* 2.23 0.61 b* -12.99 -8.08 L* 31.68 40.17 0.2% a* 1.14 -0.17 25% b* -13.98 -7.99 L* 11.27 21.84 1.0% a* 2.40 0.68 b* -12.32 -7.15 L* 37.67 0.2% a* 0.12 0% b* -10.76 L* 18.32 1.0% a* 0.83 b* -11.38

-182-