THE EFFECT OF "IMPURITIES" IN WATER

ON VAT DYEING

A THESIS

Presented to

the Faculty of the Graduate Division

by

Joseph Leo Connolly, Jr,

In Partial Fulfillment

of the Requirements for the Degree

Master of Science in Textiles

Georgia Institute of Technology

September I960

\t M "In presenting the dissertation as a partial fulfillment of the requirements for an advanced degree from the Georgia Institute of Technology, I agree that the Library of the Insti­ tution shall make it available for inspection and circulation in accordance with its regulations governing materials of this type. I agree that permission to copy from, or to publish from, this dissertation may be granted by the professor under whose di­ rection it was written, or,, in his .absence, by the dean of the Graduate Division when such copying or publication is solely for scholarly purposes and does not involve potential financial gain. It is understood that any copying from, or publication of, this dissertation which involves potential financial gain will not be allowed without written permission.

^^~f (T :. f

THE EFFECT OF 'IMPURITIES" IN WATER

ON VAT DYEING

Approvec

Date Approved : CyiXA/vu-OAM ^^, f ^ ^ I II

ACKNOWLEDGMENTS

The writer wishes to express his most sincere appreciation to

Dr. William Postman, not only for his technical advice and guidance, but also for his enthusiasm and understanding; to Dr. Robert Ingols and

Mr. Rudolph Yobs for their participation on the reading committee and for their advice and assistance in various phases of the work; to Dr.

James L, Taylor for his encouragement and understanding; to the

T. E. Stribling Foundation for the research fellowship; and to the E. I. duPont deNennours Company, Organic Chemicals Department for the donation of the dye stuffs used in this work. iil

TABLE OF CONTENTS

Page

ACKNOWLEDGMENTS ii

LIST OF TABLES iv

SUMMARY V

Chapter

I. INTRODUCTION 1

II. PROCEDURE 6

ni. DISCUSSION OF RESULTS 11

Experiments "witb Tannic Acid Experiments witb Calcium Chloride Experiments with Magnesium Chloride Experiments with Manganese Chloride Experiments with Sodium Sulfate Experiments with Sodium Bicarbonate Experiments with Sodium Phosphate

IV. CONCLUSIONS AND RECOMMENDATIONS 15

BIBLIOGRAPHY 30 IV

LIST OF TABLES

Table Page

1. Chemical Structure of Dyes 17

2. pH of Tannic Acid Experiments . , ,., 20

3. Color Coordinates and pH of Vat Blue 6 Dyeings 21

4. Color Coordinates and pH of Vat Green 6 Dyeings .... 22

5. Color Coordinates and pH of Vat Yellow 2 Dyeings ... 23

6. Color Coordinates and pH of Vat Orange 9 Dyeings ... 24

7. Color Coordinates and pH of Vat Brown 1 Dyeings ... 25

8. Color Coordinates and pH of Vat Orange 3 Dyeings ... 26

9. Color Coordinates and pH of Vat Blue 20 Dyeings .... 27

10. Color Coordinates and pH of Vat Black 27 Dyeings ... 28

11. Color Coordinates and pH of Vat Violet 17 Dyeings ... 29 SUMMARY

Water is the universal solvent and its importance to industry can­ not be over estimated. This is especially true in the textile industry and in particular in textile finishing plants. Millions and millions of pounds of textile fabrics and yarns are dyed all over the world annually.

The effect of "impurities" in water on dyeing has not been extensively studied and much has been deduced from a minimum of research work.

The purpose of this investigation was to study the effect of selected

"impurities" on the vat dyeing of cotton yarns. The particular "impuri­ ties" studied were tannic acid, sodiuna chloride, calcium chloride, magnesium chloride, manganese chloride, sodium sulfate, sodium bicarbonate, and sodium phosphate. These were added separately to dye baths in concentrations of 100 ppm. and skeins dyed by a standard procedure. The resulting dyed skeins were then compared colormetrically in a Hunter Color and Color Difference Meter. Any difference greater than a preset standard was attributed to the particular salt present in the dye bath. Dyeings in baths contairing 100 ppm. sodium chloride were used as a standard on which to base differences. Nine different vat dyes were used to check each salt.

It was found that tannic acid had no adverse effect on dyeing even at concentrations as high as 100 ppm. The only salts that caused any VI

trouble were calcium chloride and manganese chloride. Dyeing with the other salts shov/ed no adverse effects on any of the nine dye stuffs checked. CHAPTER I

INTRODUCTION

The beginnings of vat dye application can be traced back to

ancient times when textile materials were dyed with a blue coloring

matter known as indigo (C. I. Vat Blue I), The naturally occurring

coloring matter was probably used as a dye stuff as long as 5, 000

years ago(l).

Tyrian Purple, another natural dyestuff, obtained from the juices

of mollusks found on the shores of the Mediterranean Sea, was used as

a dye about 3,500 years ago. Because the quantities available were

quite smalli this dyestuff was reserved for coloring materials used

only by royalty and persons of rank.

In 1879. Baeyer succeeded in synthesizing indigo and in 1883

established the chemical configuration or structural formula. In 1897,

the first successful synthetic product was introduced to the market by

Badische.

Indanthrone, C. I, Vat Blue 4, was synthesized by Rene' Bohn in

1901 and was the first of a series of dye stuffs based on anthraquinone.

A whole new field of synthetic organic chemistry was uncovered by this discovery and additional dyestuffs in the entire range of shades were

soon developed. Many excellent accounts of the discovery and uses of the natural and synthetic dyestuffs have been written (2, 3, 4, 5). Therefore It seems unnecessary to repeat here the details of this most interesting phase in the history of vat dyeing.

Chemically, vat dyes are characterized by the qulnone groupings which they contain, and these form the basis of the method of applica­ tion. Normally insoluble in water, the dyes can be dissolved by reduction to the hydroquinone of "leuco"-compound, which is soluble in caustic soda. Cellulosic fibers rapidly adsorb such leuco-dyes from alkaline solutions at temperatures of 40-60 degrees Centigrade. After removal from the dye bath the fibers are exposed to air or a suitable oxidising agent, when the dye Is reoxidized to the insoluble qulnone in­ side the fiber itself and mechanically retained.

Every vat dye contains at least one keto group, illustrated below,

\ c- o Z' which is the group that reacts with caustic soda and sodium dithionite

(commonly, but incorrectly, called sodium hyd rosulfite) to forin the sodium enolate or the sodium salt of the enol form of the ketone, which is \ c-o // soluble in water. Inpractice the insoluble vat dye is usually first converted into a very fine aqueous dispersion to which alkali and reducing agents are added and the mixture warmed until complete reduction takes place. This process is known as "vatting". Dyeing is carried out at a comparatively low temperature, both to avoid excessive oxidation and also in order to prevent Irreversible over-reduction of the dye which can occur in many cases. Adsorption of the leuco dye is very rapid in spite of the low temperature, and one of the greatest difficulties of vat dyeing is to ensure uniform adsorption of the dye by the fiber, since migration or levelling is also retarded by the low temperature.

According to Vicker8taff(6) there are the following five stages in vat dyeing I

1. The preparation of the aqueous dispersion of the insoluble vat dye.

2. The reduction of the dye to the soluble leuco compound,

3. The adsorption of the leuco compound by the fiber.

4. The re-oxldation of the dye in the fiber,

5. The soaping after treatment.

The chemical phenomenon of vat dyeing is illustrated by the reversi­ ble chemical equation below.

OH ONa II • I r^+itHl j^+2NjaV^ y^

II I I OH OMa Because of the rapid rate of dyeing of leuco vat dyes and their poor

leveling properties, it has been found an advantage in some cases to dis­

tribute the oxidized dye unifornily through the fabric or yarn before

reducing it. This is known as the pignnentation method of vat dyeing.

A uniform distribution of the dye is obtained on the fibers so that when

they are subsequently passed through a reducing solution, reduction and

dyeing take place simultaneously in situ, and little or no migration is

needed to produce a level dyeing.

It has been stated(7) that

In the presence of polyvalent metal ions such as calcium, magnesium, aluininum, etc, , a less soluble leuco compound may form which will have little affinity for celluloslc fibers. The polyvalent metal ions may be present in the water supply, or they may leach out of the textile material.

Cockett and Hilton(8) report the following:

The Impurities present in water may be soluble or insoluble. In the latter case, filtration or settling tanks may be used to remove the solids, but soluble nnatter or hardness affects soap, dyestuffs, and finis King agents. The natural soluble impurities present in water to varying extents are dissolved gases, the sulfates and bicarbonates of calcium and magnesiunm, metallic compounds, chiefly iron, and organic matter.

These two references are representative of many which seem to indicate that the presence of metallic ions and organic matter adversely affect dyeing. None of these references refer to any work which would prove what has evidently been deduced about hardness, etc. It is assumed that dyestuff manufacturers have supported research work along these lines but have not seen fit to publish the results of their -//ork. The purpose

of this study then is to determine which, if any, additives to water have an effect on vat dyeing. CHAPTER n

PROCEDURE

Samples of so-called bad water were received from a textile finishing plant and the water was analyzed. As a result of this analysis, it was decided to study the effect of those constituents (listed below) present In the water In the highest amounts.

1. Organic Matter Z, Calcium 3. Magnesium 4. Manganese 5. Carbonate 6. Chloride 7. Sulfate 8. Phosphate 9. Sodium

Sodium chloride is commonly used in dyeing to increase the ease of adsorption of dye by the fiber. For this reason., the standard for conn- parison for all dyeings in this work is a skein dyed with the dye stuff to be studied in the presence of 100 ppm sodium chloride.

The effect of these "impurities" was studied by dyeing skeins by a standard dyeing procedure and adding one of the above "impurities" to each dyebath. The resulting dyed skeins were then compared colornnetrically, and any difference from the standard NaCl dyeing attributed to the substance added to the dyebath. All dyeings were done on ten gram skeins of scoured and bleached

24's/l cotton yarn in a bath with a 20:1. By 20:1 is meant 20 parts by weight of dye bath for every gram of fiber; since dyeings were made on

10 gram skeins, the total volume of the dye bath was 200 ml. or 200 grams,

The amount of all chemicals used was based on the weight of the fiber

(owf).

Dyeings were performed in 500 ml. porcelain beakers which were placed in a constant temperature bath with a control unit capable of main­ taining the set temperature to within plus or minus 0.05 degrees

Centigrade.

The standard procedure used in all dyeings is given below:

1. Wet out skeins at the boil in a 20:1 bath containing 5% Tergitol and 5% NaOH. After 10 minutes remove the skeins and rinse. 2. Prepare dye bath and heat to 120 degrees F. 3. Reduce the bath with 15% each of sodium hydrosulfite and NaOH and allow to sit five minutes. 4. Enter skeins into reduced dye bath and dye for 15 minutes at 120 degrees F. 5. Remove skeins and rinse In cold (tap) running water until free of NaOH. 6. Oxidize In a 20:1 bath containing 5% sodium perborate for 5 minutes at 130 degrees F, 7. Soap at the boil in a 20:1 bath containing 2% soap flakes for 5 minutes. 8. Rinse until free of soap and dry in an oven. The amount of dyestuff used was 2% (owf) or 0.02 grams for the ten gram skeins used.

After reduction and prior to placing the skeins in the dye baths, the pH of the baths was checked on a Beckman Model H-2 pH meter. For color comparisons, a Hunter Model DE5 Color and Color

Difference Meter was employed. Information on this instruments is available from the manufacturer or has been reported in current litera­ ture (9).

Using this instruinentation, standard dyeing procedure, and nine dyes of differing chemical constitutions, the effect of the following

"impurities"was studied; tannic acid, sodium sulfate, sodium phosphate, sodium bicarbonate, calcium chloride, magnesium chloride, and manga­ nese chloride.

The dyeings in tannic acid were compared with similar dyeings in

Atlanta water and also deionized water. Dyeings with salts were com­ pared with dyeings in deionized water with 100 ppm NcCl added. The selection of salts was made so that all anions had a common cation

(sodium), and all cations had a common anion (chloride).

Initial dyeings were done with 100 ppm salt additions to the dye bath.

The salt concentration was lowered to lu ppm and 5 ppm any time a total color difference of 3 units or greater showed up in comparison of the standard (NaCl) dyeing with the particular salt in question on the Color

Difference Meter.

The Color Difference Meter measures color by three color coordi­ nates: L, a, and b.

L represents lightness. a represents either greeness (-a) or redness (a). b represents either blueness (-b) or yellowness (b). The total color difference or £ is calculated by use of the following

formula: aE=(AL^ 4 A a^ i-bO

This color system is based on the National Bureau of Standards of

color difference devised by Judd(lO). It was designed to have approxi­

mate perceptual uniformity throughout the color solid. Judd adjusted

Its magnitude to make the color difference of one unit the maximuxri tolerable in the average commercial color rr.atch. However, due to the fact that the "uniform color" scales are not perfectly uniform, it is

quite possible for a difference of 1. 0 NBS unit to be visually as large as

another measuring 1.5, 2. 0, or even 3. 0 units (11). In this work, 3. 0 was selected as the maximum permissible difference because at this level was the greatest correlation between calculated and visual difference.

The color coordinates of this system can be converted to the X, Y, Z values of the International Committee on Illumination (I. C. I. ) color system by appropriate equations.

The dyestuffs used were selected so as to have differing chemical constitutions. The structural fornrxulas for these dyes can be found in the

Appendix. Nomenclature is that used in the Colour Index(12). The following dyestuffs were used:

Vat Blue 6 C. I. 69,825

Vat Green 1 C. I. 59,825 10

Vat Yellow 2 C.I. 67,300

Vat Orange 9 59,700

Vat Brown 1 70,800

Vat Orange 3 59.300

Vat Blue 20 59,800

Vat Black 27 69,005

Vat Violet 17 63.365

Tbe dyestuffs were obtained in the form of pastes, and standard solutions of each were prepared so as to reduce the error in weighing such small quantities. 11

CHAPTER m

RESULTS AND DISCUSSION

Experiments with Tannic Acid.»"Dyeings with tannic acid were first carried out using only 5%(owf) each of NaOH and sodium hydrosulfite in the dye bath. After five minutes of dyeing it was necessary to add more of the above to keep the bath reduced. Additions totaling 15% each of

NaOH and "Hydro" were made before the fifteen nainute dye-period was ended, and it was decided to use 15% NaOH and "Hydro" in all future dyeings.

There was no visual difference between skeins dyed in baths con­ taining tannic acid and those dyed in baths with only Atlanta and deionized water.

It was noted that the reduced dye bath containing tannic acid had a different color than other baths but the skeins from these baths were not affected by this difference. Investigations showed that tannic acid dissolved in water is slightly yellow but when NaOH is added to the solution, it turns brown. However, when the bath is neutralized with acid, the dark color fades and the solution returns to its original color. This is due to tannic acid's being an indicator.

The pH of dye baths with and without tannic acid was checked but no significant difference was found. The results of the pH checks are given in the Appendix. 12

The per cent available Hydrosulfite in the reduced dye baths was also checked. In order to test for this per cent, the Iodine Method of analysis was used. This Is the American Association of Textile

Chemists and Colorlst official Iodine Method Number 69(13) and has the advantage that It may be carried out In the presence of air without special apparatus.

The results of this check showed that a dye bath containing tannic add had only 2% less available "hydro" than the same dye bath without the acid. A difference of 2% is not significant since dyeing Is carried out with an excess of both "hydro" and caustic soda well above the 2% level.

Based on the results of these experiments, It does not seem that tannic acid has any effect on vat dyeing. It does not significantly lower the pH or available hydro, and causes no change in the resulting finished dyeings.

Experiments with Calcium Chloride. --The calcium ion is one of the ions that accounts for hardness In water and Is said to Interfere and adversely affect dyeing. "When added to a dyebath at the 100 ppm level, It did not affect all dyes but had a noticeable effect on Vat Blue

6, and Vat Orange 9. Skeins dyed with the other seven dyes did not have a color difference of 3. 0 or greater. The results of the color connparlsons of all dyes can be found In the Appendix.

Skeins dyed with Vat Orange 9 and 100 ppm calcium chloride had a 13

color difference of 3.69, and when tKe calcium chloride was dropped to

I J ppm the color difference dropped to 1. 03, which ia not objectionable.

The skeins dyed with Vat Blue 6 had a color difference of 5. 28 with calcium chloride at the 100 ppm level. When calcium chloride was

dropped to 10 ppm, the color difference was 3.91. However, at the 5

ppm level, the difference dropped to 2.91 which is within the tolerance limits.

The presence of any ion in water at or above the 10 ppm level could in aU probability be remedied by the proper treatment. In any

case it appears that if the calcium Ion Is present in quantities as low

as 10 ppzn It possibly can Interfere with dyeing, especially Vat Blue 6.

Experiments with Magneslumi Chloride, --Magnesium chloride showed no adverse effects on any of the dye stuffs used when added to the dye bath at 100 ppm. This was somewhat surprising as several references re­ ferred to magnesium as one of the polyvalent ions supposedly affecting dyeing. The results of this work would seem to repudiate this.

Experiments with Manganese Chloride. --Dye baths containing this Ion had an adverse effect on skeins dyed with Vat Yellow 2, Vat Orange 9 and Vat Orange 3. It is interesting that only the yellow and orange dyes were adversely affected. The reduced baths containing each of these dyes was not the same color as the same baths containing other metallic ions but the baths were darker and dirty looking. The resulting skeins also had a dirty brownish look as compared to the other skeins. When 14

the manganese concentration was dropped to 10 ppm, no visual difference was noted and the Instrumental color difference dropped below 3. 0 with all the dyes.

Experiments with Sodium Sulfate, --The presence of sodium sulfate In the dye bath had no effect on the skeins dyed In these baths. A slight difference in pH was expected but this was not significant.

Experiments with Sodium Bicarbonate. --The presence of the bicarbonate anion had no effect on dyeing or pH.

Experiments with Sodium Phosphate.--The phosphate Ion also showed no adverse effect on dyeing. The resulting dyed skeins showed no signifi­ cant color difference and the pH did not vary. 15

CHAPTER IV

CONCLUSIONS AND RECOMMENDATIONS

Based on the experimental work performed and just discussed, it seems that the presence of tannic acid in water even as high as 100 ppm has no adverse effect on dyeing with vat dyes. The reduction color of the dye bath may vary from normal but this has no effect on the final oxidized dyeing. It is recommended that further work be done on the effect of tannins in forms other than tannic acid. This still seems like a reasonable source for the difficulty since so many dyeing or finishing plants have trouble every fall when the rain extracts so m.uch color from the rotting foliage on the ground.

It does not appear that any anion has a harmful effect on vat dyeing, at least when It is in solution with the sodium cation. Cockett and Hilton

(14) reported that calcium and magnesium sulfates are the cause of

"permanent" hard water which interferes with some finishing processes.

Experiments using these anion-cation combinations seem warranted and should be carried out.

The cations calcium and manganese caused some trouble as reported, but not with all dyestuffs. The effect of these cations on a wider range of dyes should be Investigated as well as these same cations in combina­ tion with different anions. If either of these cations was found in 16

commerciad water in concentrations as high as 10 ppm there is a possibility that difficulties could be encountered. This seems more readily possible with calcium than with manganese which gave no trouble when reduced from 100 to 10 ppm.

As Vickerstaff(15) points out, there has been relatively little research on dyeing with vat dyes. He states that "the neglect of the process from the research view is probably due to greater complexity and instability of the dyeing system. " More work needs to be done on vat dyeing and especially as to the effects of electrolytes in the dye bath. APPENDIX 17

Table 1. Cbemical Structure of Dyes

Vat Blue 6 C.I. 69. 825 0 II CkjX^

0 H n -H

II ^\l 0 Vat Bleu 20 C.I. 59 ,800

Vat Orange 3 C.I. 59,300

Vat YeUow 2 C.I. 67.300 0 S-C-/ > II » il >s /

..CXOII I II " S 0 (y- 18

Table 1. Contiaaed

Vat Black 27 C.X. 69.005 Q

cco-oon o Ml NM M\H W O-co- --Q Vat Green I C.I. 59,825

I I H3CO OCH3 Vat Violet 17 C.I. 63,365

o,« ?, ?-oc/ ^ocH ^coo o Vat Brown I C. L 70, oOO

-NH-/ >^NM

sO 0:< VO 0:/ >=:0 19

Table I. Contiaaed

Vat Orange 9 C.I. 59,700 20

Table 2. pH of Dye BatbB Containing Tannic Acid

Time of Check No Tannic Acid With Tannic Acid

1. Initial 12.3 12.1

2. After 1 nun. 12.2 12. 1

3. After 5 xnin. 12.2 12.1

4. After 10 min. 12.1 12.1

5. After 15 mln. 12.1 12.0 21

Table 3. Color Coordinates and pH of Vat Blue 6 Dyeings

Salt L a b £ pH

1. NaCl 38.1 3.7 -32.9 11,8 38.0 3.9 -32.7 2. CaCl2 42.2 2.0 -30.6 11.7 42.9 2.0 -30.4 5.28 3. MgCl2 40.3 3.3 -31.8 11.6 40.1 3.4 -31,8 2.36 4. MnCl2 40.6 2.0 -29.2 11.6 40.0 2.0 -28.5 2.91 5. Na2S04 40.0 39 -32.0 11.6 39.9 4.0 -31.9 1.97 6. NaHCOj 37.6 3.0 -32.6 11.6 38.3 3.1 -32.3 0.94 7. Na3P04 39.0 2.0 -30.8 11.6 38.7 2.1 -30.7 2.72 8. CaCl^* 40.6 2.2 -30.8 11.7 40.2 2.1 -31.2 3.91 9. CaCl2** 39.1 2.2 -31.5 11.7 39.0 2.1 -31.4 2.91

* Dyed with 10 ppm calcium chloride.

*• Dyed with 5 ppnn calcium chloride. 22

Table 4, Color Coordinates and pH o£ Vat Green 6 Dyeings

Salt L a b E pH

1. NaCl 45,45.0 -28.0 -3.6 11.8 44.9 -28.2 -3,-3,77 2. CaClCaCl->^ 46.4 -28-28.. 55 -3.5 11.7 46.0 -28.4 -3.5 1.28 MgCl2 46.3 -28.8 -3.6 11.7 47.1 -28.8 -3,7 1 84 4. MnCl?2 46.7 —-28. 282. 2 -3.2 11.6 46.5 -28.1 -3.1 1.68 5. Na:>SONa2S0A4 46.5 -29.0 -3.•3.9 11.6 46.9 -28.5 -3.4 1.81 NaHC03 45. 1 -28.5 -3.5 11.6 45.2 -28.4 -3.4 0.46 7. Na^PONajPO^ 45*45.2 -28.3 -3.7 11.7 45.2 -28.5 -3.8 0.32

Jk 23

Table 5. Color Coordinates and pH of Vat Yellow 2

Salt L a b E pH

1. NaCl 82.8 -12.5 45.6 11.8 82.0 «12.3 45.8 2. CaCl2 81.3 -13.4 46.0 11,8 81.6 -12.8 46.2 1.03 3. MgCl2 82.2 -14.0 45.2 11.7 82.1 -14.3 44.8 1.93 4. MnCl2 77.1 -10.0 43.3 11.7 77.3 -10.0 43.6 5.92 5. Na^SO. 80.3 -14.1 44.8 11.6 80.5 -14.1 44.5 2.64 6. NaHC03 81.9 -13.0 46.3 11.6 8L9 -12.3 46.5 0.7 5 7. Na3P04 82*0 -13.8 45.4 1.41 11.5

8. MnCl^^ 80.7 -11.6 45*2 11.6 82»7 -11.0 44.2 1.61

• Dyed with 10 ppm Manganese chloride. 24

Table 6. Color Coordinates and pH of Vat Orange 9 Dyeings

Salt La b E pH

NaCl 59.7 29,5 36.5 11.7 59.9 29.4 36.5 CaCl, 60.0 27.2 35.8 11.7 59,7 26.8 35.3 3.69 MgCl2 5B. 1 31.6 35.9 11.7 57.8 31.6 36,0 2.88 MnCl2 56.5 2G.9 34.9 11.6 56.7 29.1 35.1 3.57 Na2S04 60.3 29.9 36.7 11.6 60.3 30.0 36.6 0.73 NaHCOj 59.8 29.1 36.7 11.6 59.9 29.6 36.6 0.14 Na.PO. 61,1 23.6 36*4 11.5 61,4 28.7 36.3 1.70 CaCl,* 59.6 28.4 36.4 11.7 59.7 28.5 36.4 1.03 MnCl2** 57.2 30. 6 35.0 11.5 57.7 29.9 35.2 2.73

^ Dyed •with 10 ppzzi calcium chloride.

•• Dyed with 10 ppm manganese chloride. 25

Table 7. Color Coordinates and pH of Vat Brown 1 Dyeings

Salt h a b £ pH

X. NaCl 43,8 10.7 9.3 11.8 44.4 10.7 9.1 2. CaCU 43.8 1C.5 9.0 11.6 44.0 10.3 9.1 0.37 3. MgCl2 44.2 10,0 9.3 11.7 45,3 10.1 9.3 0.74 4. MnCln 44,4 10.1 9.5 11.6 44.0 10.4 9.8 0.60 5. Na^SO^ 41,7 1C.8 9.0 11.7 43,3 10.9 9.0 1.42 6. NaHC03 44,3 11.3 9.2 11.6 44,6 11.1 9.4 0.59 7. Na3PO^ 42,6 10.4 9.0 11,6 42«8 10.2 9.0 1.47 26

Table 8. Color Coordinates and pH of Vat Orange 3 Dyeings

Salt L. a b £ pH

NaCl 61.4 37.4 22.3 U.7 61.2 37.7 22.22.44 CaCl, 62.3 37.7 22.2 11.6 62.3 37.8 22.6 1.01.022 MgCl^ 61.9 36.5 22.1 11.6 61.6 37.3 22.5 0.60,622 MttCl^ 60.2 34.9 21,7 11.6 60.4 34.9 21.9 3.85 NazSO^ 62.5 37.8 22.6 11.5 62.4 38.1 22*7 1.19 NaHC03 61.6 37.5 22.2 11.6 6U4 37.4 22.3 0.24 Na3PO^ 63.1 38.7 22.3 llt6 63.0 38.5 22.3 1.97 MnCl2* 64.6 38.3 21.2 1 11.7 64.7 38.4 21.1 1.98

Dyed with 10 ppm manganese chloride.

J 27

Table 9. Color Coordinates and pH of Vat Blue 20 Dyeings

Salt £ pH

I. Naa 26.0 7.0 -17.7 11.8 25.4 7.1 -17.7 2. CaCL 26.7 6.5 -17.3 11.7 27.4 6.8 -17.8 1.37 3. MgCl2 25.5 6.8 -16.8 11.7 25.5 6.8 • 16.9 0.94 4. MnCl- 24.6 6.5 -17.1 11.6 24.8 6.2 • 16.8 1.37 Na2SO^ 22.9 6.2 -16.5 11.7 23,3 6.6 -16.9 2.76 NaHCO, 23.4 6.8 -17.2 11.6 24.3 6.4 -18.8 1.96 Na3PO^ 28.7 6.1 -17.4 11.6 27.0 6.0 -17.3 1.86 28

Table 10. Color Coordinates and pH of Vat Black 27 Dyeingt

Salt L a b E pH

1. NaCl 4U5 -0.6 5.1 11.7 41.0 -0.9 5.1 2. CaCl2 39.9 -0.8 5.1 11.7 41.1 -0.4 5.1 0.905 3. MgCl2 39.2 -1.5 4.9 11.6 38.9 -1.3 5.0 2.22 4. MnCU 39.1 -2.2 5.2 11.6 39.2 -2. 2 5.4 2.59 5. Na2S04 38.7 -1.6 4.8 11.6 39.4 -2.1 5.0 2.43 6. NaHC03 38.5 -0.7 5.1 11.6 38.8 -0.7 5.0 1.7 7. Na3P04 38.8 -1.6 5.1 11.6 38.9 -1.9 5*1 2.67 29

Table 11, Color Coordinates and pH of Vat Violet 17 Dyeings

Salt L a b £ pH

1. NaCl 29.4 22.7 • 28.8 11.8 29.6 22.4 -28.4 2. CaCl2 28.3 21.3 -27.5 11.7 29.2 21.9 -27.5 1.51 3. MgCl2 29.8 21.6 -27.7 11.6 30.6 21.7 -28.4 1.37 4. MnCl2 30.6 21.7 -28.4 11.7 30.9 22.0 -28.4 1.34 5. Na2SO^ 30.2 21.7 -27.2 11.7 29.9 22.2 -28.0 1.27 6. NaHCOj 28.8 £i£t% it -27.6 11.6 28.8 22.2 -27.8 1.42 7. Na3P04 30.6 21.6 -26.9 11.7 30.4 21.3 -27.5 2.04

NH^^, A

''"

BIBLIOGRAPHY

1. Postman, William, "The Basic Chemistry of Dyes and Dyeing" Textile World. August 1959, Vol. 109, No. 8, p. 5.

2. Thorpe, J. F., and Ingold, G. K., Vat Colors. New York: Longmans, Green and Company, 1923.

3. Hurry, J. B,, The Woad Plant and Its Dye. Oxford University Press, 1930.

4. Fox, M, R., Vat Dyestuffs and Vat Dyeing. New York: John Wiley and Sons, Inc., 1948.

5. "The Application of Vat Dyes", American Association of Textile Chennists and Colorists, Monograph No. 2, 1953.

6. Vickerstaff, Thomas, The Physical Chemistry of Dyeing. New York; Interscience Publishers Inc., 1954, p. 281.

7. "The Application of Vat Dyes", 0£. clt., p. 27,

8. Cockett, S* R*, and Hilton, K. A*, Basic Chemistry of Textile Preparation. London: National Trade Press Ltd., 1955, p. 111.

9 Hunter, R. S., "Photoelectric Color Difference Meter" Journal of the Optical Society of America, Vol. 48, No. 12, pp. 985-995, December 1958.

10 Ibid., p. 986.

11. "Instructions for Hunter Model D25-B Color and Color Difference Meter", McLean, Virginia: Hunter Associates Laboratory, Inc., 1957. (Mimeograph)

12. Colour Index. 2nd Ed., Bradford (England): Society of Dyers and and Colourists and The American Association of Textile Chemists and Colorists, 1956-1958,

13. "Iodine Method of Analysis of Sodium Hydrosulfite" Rohm and Haas Technical Bulletin, No. T-9a: Philadelphia, Pennsylvania, Rohm and Haas Company, 1951, p. 13. 31

14. Cockett and Hilton, og^. cU. , p. 112,

15. Vickerstaff. 0£. cit., p. 280.

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