Australian Mohair - Processing Performance and Fabric Properties Publication No 99/139 Project No
Australian
Mohair Processing Performance and Fabric Properties
A report for the Rural Industries Research and Development Corporation
By Xungai Wang, John Curiskis, Jeff Zhou
October 1999
RIRDC Publication No 99/139
RIRDC Project No UNS-8A
© 1999 Rural Industries Research and Development Corporation. All rights reserved.
ISBN 0 642 57990 3 ISSN 1440-6845
Australian Mohair - Processing Performance and Fabric Properties Publication no 99/139 Project no. UNS-8A
The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report.
This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186.
Researcher Contact Details A/Prof. Xungai Wang Dr John Curiskis School of Engineering & Technology Department of Textile Technology Deakin University University of NSW Geelong Sydney VIC 3217 NSW 2052
Phone: (03) 5227 2894 (02) 9385 4458 Fax: (03) 5227 2167 (03) 9385 5953 E-mail: [email protected] [email protected] Website: http://www.deakin.edu.au http://www.unsw.edu.au
RIRDC Contact Details Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600
PO Box 4776 KINGSTON ACT 2604
Phone: 02 6272 4539 Fax: 02 6272 5877 E-mail: [email protected] Website: http://www.rirdc.gov.au
Published in October 1999 Printed on environmentally friendly paper by Canprint
ii
FOREWORD
The main objectives of this project were to overcome problems associated with processing Australian mohair and mohair blends, and to develop new fabrics using Australian mohair.
Australia's annual mohair production is around 0.5 million kg and virtually all of this is exported in raw form to Europe and Asia for further processing. Little processing research and product development work on this luxury fibre has been carried out in Australia. The lack of basic and applied research will undoubtedly put the Australian goat fibre producers in a vulnerable position.
This research has systematically examined Australian mohair from raw fibre to finished fabric. Numerous technical problems associated with the processing of mohair and mohair blends have been tackled during the course of this research, and several innovative approaches have been developed. This research has also resulted in the development of several very promising mohair fabrics. Whenever possible, objective measurements on fibres, yarns and fabrics have been used.
The results gained in this research will provide useful information for existing mohair/related processors and will encourage the establishment of further local mohair processing which would strengthen the industry and improve the financial return to primary producers. Some suggestions for future research are also given in the end of this report.
This report, one of RIRDC’s diverse range of 400 research publications, forms part of our Rare Natural Animal Fibres R&D program, which aims to facilitate the development of new and established industries based on rare natural fibres.
Most of our publications are available for viewing, downloading or purchasing online through our website: • downloads at www.rirdc.gov.au/reports/Index.htm • purchases at www.rirdc.gov.au/pub/cat/contents.html
Peter Core Managing Director Rural Industries Research and Development Corporation
iii Contents
Foreword iii
1. EXECUTIVE SUMMARY 1
2. INTRODUCTION 2.1 Research background 2 2.2 Mohair fibre 4 2.3 Mohair processing 6
3. AUSTRALIAN MOHAIR AND ITS PROCESSING 3.1 Australian mohair classification and composition 8 3.2 Fibre length measurement 9 3.3 Fibre diameter measurement 10 3.4 Fibre diameter and prickle effect 11 3.5 Mohair top-making 13 3.6 Mohair yarn spinning 17
4. SOLUTION TO PROCESSING PROBLEMS 4.1 Combing machine adjustment 19 4.2 Improving sliver strength 20 4.3 Reducing yarn hairiness 23 4.4 Producing low and twistless mohair yarns 29
5. MOHAIR KNITTED FABRICS 5.1 Traditional products 34 5.2 Development trends 34 5.3 Spinning of mohair knitting yarns 35 5.4 Mohair knitted fabrics 35 5.5 Knitted sample fabrics for the final report 36
6. Mohair Woven Fabrics 6.1 mohair fabrics with different wool composition 37 6.2 Processing of two mohair worsted fabrics in industry 38 6.3 Test results for worsted mohair and wool fabrics 42
7. Conclusion and Suggestion for Further Work 53
References 54
Appendix 1: Mohair knitting yarns I 57 Appendix 2: Mohair knitting yarns II 59 Appendix 3: Test results for worsted mohair and wool fabrics 60
8. RIRDC Publications 53
iv
1. EXECUTIVE SUMMARY
The original objectives of this project were to: • Identify and evaluate problems in worsted processing of Australian mohair and mohair blends • Examine the effect of mohair/wool blend ratio on the processing and product performance. • Optimise the processing performance of mohair and mohair blends based on objective measurements of both raw and processed materials • Assist with the establishment of an exotic fibre processing base in Australia through technology transfer, which will eventually add value to Australian rare natural fibres.
During the consultation process with industry at the initial stage of the process, it was thought necessary to have a focus on development of new products. For this focus to materialise, it was necessary to overcome the problems associated with mohair processing first. In addition, developing new products entailed the developments of new yarns. These tasks have been achieved through a systematic study on Australian mohair and blends from raw fibre to finished fabric. Numerous technical problems associated with the processing of mohair and mohair blends have been tackled during the course of this research, and several innovative approaches have been used in this research. This research has also resulted in the development of several very promising mohair fabrics, and some fabric samples are provided in a separate sample book. Whenever possible, objective measurements have been used. This research has also provided research training to two Masters students. The first student has successfully completed his Masters degree and is now pursuing his PhD research at Deakin, while the second is in the final stage of completing her Masters research at UNSW. The Master students’ work is documented in their theses and will not be repeated in this report.
In summary, this research has met its main objectives. It is believed that the results gained in this research will provide useful information for existing mohair/related processors and will encourage the establishment of further local mohair processing which would strengthen the industry and improve the financial return to primary producers. Some suggestions for future research are also given in the end of this report.
1 2. INTRODUCTION
2.1 Research background
Table 1 shows world mohair production in recent years. Australia's annual mohair production is around 0.5 million kg and virtually all of this is exported in raw form to Europe and Asia for further processing. Little processing research on this luxury fibre has been carried out in Australia. The lack of basic and applied research will undoubtedly put the Australian goat fibre producers in a vulnerable position. As a scientist from SAWTRI put it at the 1985 Annual IMA Conference, without the availability of sound scientific knowledge on the processing performance and characteristics of the mohair fibre, any industrialist wishing to enter the field for the first time is placed at a significant disadvantage. Ultimately, therefore, so also is the mohair fibre producer. The importance of processing research for the goat farmer is actually quite obvious. For example, in the mid 1970s, the average price of South African seedy mohair was increased significantly after research findings which indicated that very seedy SA mohair (up to 15% VM) could be combed almost clean by using the French comb and that uncarbonised mohair, combed on the French comb, appeared to be more lustrous, had a longer mean fibre length and a better colour than carbonised mohair [Turpie et at 1994].
Table 1: World Mohair Production by Main Producing Countries (m kgs) Year S. Africa USA Turkey Argentina Lesotho Australia NZ Misc. TOTAL
1982 7.6 4.5 4.5 1.0 0.5 - - - 18.0 1983 7.5 4.8 4.5 1.3 0.67 - - - 18.77 1984 8.1 5.1 3.5 1.0 0.75 0.5 0.05 0.05 19.05 1985 9.1 5.4 3.5 1.1 0.8 0.5 0.07 0.06 20.53 1986 11.0 5.6 3.5 1.25 0.8 0.6 0.14 0.07 22.26 1987 12.0 6.8 3.5 1.5 0.8 0.8 0.25 0.08 25.73 1988 12.5 7.0 3.0 1.5 0.6 1.0 0.35 0.1 25.95 1989 11.6 6.8 2.0 1.2 0.6 1.0 0.5 0.2 23.9 1990 10.8 6.8 1.8 1.0 0.5 1.0 0.5 0.2 22.6 1991 7.6 6.8 1.5 0.8 0.5 0.6 0.4 - 18.2 1992 6.7 6.8 1.2 0.6 0.5 0.5 0.3 - 16.6 1993 5.8 5.6 1.0 0.5 0.4 0.5 0.2 - 14.0 1994 5.7 5.4 0.8 0.4 0.4 0.4 0.2 - 13.3 1995 5.4 5.4 0.6 0.5 0.4 0.5 0.2 - 13.0 1996* 5.1 3.8 0.6 0.5 0.5 0.5 0.2 - 11.2 Source: International Mohair Association, May 1996 (* Projection).
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Australian mohair is renowned for its many desirable features such as lustre, fineness, softness and high scouring yield. But this quality image has been marred by its high kemp content. The fibre in general is regarded as low quality, but this is rapidly improving with the recent introduction of exotic genetics, such as Texan and South African. The Texan infusions have led to a dramatic reduction in the levels of kemp in the Australian mohair clip, which can now rival clip from South Africa and Texas. Australia has the potential to produce world class mohair at a competitive price.
One of the major problems facing the Australian mohair industry is one of volume. There is minimal downstream processing of mohair in Australia. A number of local wool processors are willing and able to process mohair, but their involvement largely depends on the increase in volume of mohair produced in Australia. Another problem facing the Australian mohair industry is the secrecy of overseas processing know-how. Countries that process the bulk of the international mohair clip, such as the United Kingdom, have built up their specialised processing knowledge and keep a close guard on their know-how to maintain a competitive edge. Such secrecy does not help the declining trend in world mohair production as indicated in Table 1. Processing monopoly often leads to reduced raw material cost because of the processor’s bargaining power, and to higher product cost to mohair end users because of the lack of competition and efficiency. According to Professor Thian Hor The of E (Kika) de la Garza Institute for Goat Research at Langston University (Okla.), there is a potential market of US$3-4 billion worldwide for mohair sweater producers, but one major factor hindering mohair is the high processing cost, which can run at US$10-20 per lb [Textile World, Dec. 1993, p67]. It is hard not to expect that consumer interest and incentive for goat farmers would wane as a consequence.
In order to promote consumer preference for textile products made from natural fibres, it is important to be able to objectively specify the properties of Australian mohair and assess its processing performance and subsequent fabric properties. Australia is world famous for its research and practice not only in objective specification and processing of wool, but also in fabric objective measurement. There is no reason why this cannot happen for rare natural fibres like mohair as well, given that about 70% of the mohair clip is processed on the worsted system. The current research effort is therefore highly relevant to the mohair
3 Final Report Processing Performance and Fabric Properties of Australian Mohair
industry because it aims to evaluate the problems in mohair processing and improve its processing performance and efficiency. The research findings from this project will be valuable for local topmakers who are interested in processing mohair or its blends. Since mohair is better processed when blended with other fibres like wool, there are spin-offs for the wool industry as well. Ultimately, research on mohair processing and product development in Australia will help materialise Australia’s potential for exporting processed or semi-processed mohair products.
2.2 Mohair fibre
Mohair is one of the most luxurious and fashionable fibres worldwide. Due to the competition in world fashion market, little information has been available on the processing performance and characteristics of mohair fibres, particularly Australian mohair fibres. The few enterprises in the world that specialise in mohair processing treat their technology and know-how as guarded secret in order to maintain their competitive advantage in the market.
This research has benefited from two major reviews on mohair fibres and its processing, by Hunter (1993) and by Leeder, McGregor and Steadman (1992). Being a major speciality animal fibre, mohair has a reputation for the following characteristics:
• low flammability, low felting and pilling propensity, • good durability, elasticity, and resilience, • unique lustre and drape, • good resistance to soiling and abrasion, • ideal moisture absorption, insulation and comfort properties.
Mohair’s good lustre, smoothness, low friction, low soiling and low felting are all related to its faint surface scale structure. These characteristics make mohair fibre very desirable in appearance, and delicate and smooth in handle. Figure 1 shows the scales of wool and mohair.
4 Final Report Processing Performance and Fabric Properties of Australian Mohair
Figure 1: The scales of mohair (left) and wool (right) (Knott 1990).
The surface scales of mohair fibre do not protrude appreciably above the fibre surface. The height of the mohair scale is about 0.4 µm compared with 1.3 µm for merino wool. In addition, the scales of mohair fibre are larger than the scales on merino wool. Consequently, there are fewer scales per length along the mohair fibre, typically only 50 scales per mm along the fibre length - see Table 2 below.
Table 2: Scale dimensions of some wool and mohair fibres Fibre type Diameter (µm) No of scales per mm Scale height (µm) Crossbred 46’s 38 62 1.1 Merino 60’s 25 72 1.3 Romney 48’s 35 66 1.1 Mohair 34 50 0.4
Mohair fibre has less friction than wool (Table 3), and this is also primarily due to its smooth surface.
Table 3: Frictional coefficients of wool and mohair (Frishman et al, 1948) µ1 – against scale µ2 – with scale µ1-µ2 Wool 0.40 0.22 0.18 Mohair 0.23 0.15 0.08
From the above figures, it can be seen that the coefficients of friction of wool fibres, both with and against scales, are higher than the corresponding values of mohair fibres. Further, the difference between the friction coefficients against scale and with scale for wool is
5 Final Report Processing Performance and Fabric Properties of Australian Mohair
larger than the corresponding difference for mohair fibres. This explains the low felting propensity of mohair compared to wool.
Mohair fibre has the disadvantage of being thick in diameter as compared to merino wool and some other animal fibres. With the same number of fibres per cross section, the coarser the fibre the thicker the yarn. Usually, it is very difficult to spin pure mohair yarns below a count of 30 tex, even with fine kid mohair. It is therefore very important to improve fineness of mohair fibre in mohair breeding programs in order to achieve finer yarn counts. At the same time, effort should be given to improving spinning technology in order to spin fine yarns with thick mohair fibres. Australian mohair is generally considered to be 2 µm finer than mohair produced in other countries – see Table 4. This is definitely one advantage of Australian mohair industry.
Table 4: Comparison of mohair fibre diameter ( µm ) Fine kid Kid Young Fine hair Hair Australia 23 – 24 25 – 27 28 – 30 32 – 35 36 – 40 South Africa 24 – 28 29 – 30 31 – 34 34 – 36 37 – 44
It is worth giving a little more consideration to the lustre of mohair fibres. The term ‘lustre’ refers to the manner in which light is reflected from a fibre surface. Since the surface of mohair fibres is smooth, it reflects light more uniformly compared to wool fibres. Another factor is the shape of the fibre cross-section, which also affects the degree of lustre. Mohair fibres have a regular, circular cross-section, which further contributes to its lustre. After dyeing, mohair fibre is able to produce rich, brilliant colours - this property has won the name of ‘Diamond fibre’ for mohair.
2.3 Mohair processing
It is well recognised that mohair fibre is one of the most difficult fibres to deal with in processing. The problem is also linked with the smooth surface of the fibre and the lack of cohesive force in mohair fibre assemblies such as slivers and rovings. Mohair sliver is extremely weak and breaks easily during processing. In addition, the coarseness of mohair fibre is another factor that affects its processing ability and imposes some limitation on certain apparel applications. During spinning there exists a limit on the minimum number of fibres per yarn cross section according to the Martindale theory (Martindale 1945). This limitation means that with the same number of fibres per yarn cross section the thicker the
6 Final Report Processing Performance and Fabric Properties of Australian Mohair
fibre the coarser the yarn. Usually the finest pure mohair yarn that can be commercially spun is about 30 tex.
Mohair fibre is an animal fibre similar to wool and is processed in the same system as wool. There are two worsted systems for processing wool. One is the Bradford Worsted System on which mohair fibres were traditionally processed. The other is The Continental Worsted System. Today, mohair is mainly processed on the Continental system.
These two systems are quite different in the machinery employed. There are generally considered to be fewer problems in processing mohair on the Bradford Worsted System as compared to the Continental Worsted System, especially in the combing process. Therefore, more research work has been concentrated on processing mohair on the latter system.
The normal worsted processing sequence for mohair can be divided into two stages, viz. top making and yarn spinning, with the individual steps summarised below:
Mohair top making Mohair yarn spinning • Classing • Spinning • Scouring • Winding • Opening and blending • Doubling • Carding • Ply-twisting • Gilling before combing • Winding • Combing • Top finishing – gilling after combing
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3. AUSTRALIAN MOHAIR AND ITS PROCESSING
3.1 Australian mohair classification and composition
Australian mohair fibres are classified as Fine Kid, Kid, Young Goat, Fine Hair and Hair:
• Fine Kid. Two lines are available for the finest fleece mohair - MAFK for the longer type between 125 and 170 mm; MBFK for fibres between 100 and 125 mm.
• Kid. These lines contain the remaining first shearing fleece, most of the second shearing fibre and some finer fibre from the third shearing. A and B lengths are also classified.
• Young Goat. These lines are for mohair from young animals shorn at the second to fifth shearing. The fleece exhibits a fine appearance, is stronger than KID, but does not have the broad crimp of Fine Hair. AYG and BYG are divided according to their length.
• Fine Hair. These are the largest lines since adult fleeces are much heavier in weight. A and B lengths are also used.
• Hair. Broad fibre from old does and adult bucks is placed into these lines. A and B lengths are mixed and some kemp is tolerated.
Based on the sale summaries of National Mohair Pool P/L for the period of 1995 to 1997 June, the composition of the Australian mohair clip was determined. This is summarised in Table 5. Clearly, Fine Hair mohair fibres make the bulk of the Australian clip.
Table 5: Composition of the Australian mohair clip Diameter mm Net Weight kg Percentage % Fine Kid 23.3 – 25.4 6331 4.5 Kid 24.3 – 27.7 20538 14.5 Young Goat 28.7 – 31.7 28552 20.2 Fine Hair 31.0 – 35.6 81555 57.5 Hair 34.4 – 39.4 4322 3.1
8 Final Report Processing Performance and Fabric Properties of Australian Mohair
3.2 Fibre length measurement
Fibre length can be easily measured using the Almeter instrument when fibres are in sliver form. For scoured mohair fibres, however, it is difficult to use this instrument because fibres are not in sliver form. In order to use the Almeter, scoured mohair fibres have to be transformed into sliver.
A method has been developed to fulfil this task. A small wire clothed cylinder was used. Mohair fibres were manually arranged straight and parallel onto the surface of the cylinder as evenly as possible in the form of a narrow band around the cylinder. Then the fibres were forced to sink into the wires to enable more fibres to be overlapped on top of the previous layer. After placing a certain amount of fibres onto the cylinder, the fibre band formed on the surface of the cylinder was carefully taken out of the wires in the form of a sliver with the assistance of a needle. This sliver was ready to be used in to measure fibre length. Since scoured fibres were taken before carding, the resulting measurement can be regarded as the original length of the mohair fibre before mechanical processing. By comparison of the original length and the length after processing, the damage to the fibre by mechanical processing can be estimated.
All test results of fibre length after scouring are summarised in Table 6. It seems that MAH mohair had longest fibre length and less short fibres. MAFK mohair fibre had shortest length and more short fibres. Generally speaking the lengths of all mohair fibres are long enough to not cause any problems in processing.
Table 6: Summary of fibre length measurement of Australian mohair fibres after scouring Length (mm) Length CV% < 30 mm % > 1% mm MAFK 84.8 52.4 16.2 165.0 MAK 105.7 46.6 12.9 176.9 MAYG 113.8 37.1 8.0 167.8 MAYG-BUCK 119.8 30.2 4.5 170.3 MAFH 117.6 38.0 8.0 176.4 MAH 157.1 41.8 7.6 240.1
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3.3 Fibre diameter measurement
Fibre diameter can be measured on the OFDA instrument – Optical–based Fibre Diameter Analyser. OFDA allows rapid and accurate measurement of fibre diameter.
It is reported that if either wool or mohair were tested using the wool calibration, the results at the fine end of the diameter range were about 0.6 µm lower than if the samples were tested using the mohair calibration. The proportional difference decreased as the diameter level increased, finally approaching 0.7 µm at the 37 µm diameter level. The results for standard deviation were also different. This indicated that there was a need of calibrating OFDA using standard mohair tops.
In order to calibrate the OFDA instrument, eight standard calibration mohair tops ranging from 22.3 µm to 43.1 µm were purchased from IMA. With the factory setting, the equation for mean fibre diameter was Mean = - 1.2952 + 4.7761 * (OFDA No.). After calibration, the new equation for mean mohair fibre diameter was Mean = - 0.6752 + 4.6356 * (OFDA No.).
Table 7 presents the results of the OFDA tests of various Australian mohair fibres. The fibre samples were taken from mohair tops, not from mohair fleece. In the top form, it was believed that fibres would be thoroughly mixed and they would better represent the real fineness distribution of the mohair fibre mass. However, the results may differ slightly from results obtained from raw mohair due to fibre the small changes in fibre diameter during fibre processing.
Table 7: Fibre length distribution (OFDA) of mohair tops Mean µm SD µm CV % Size 1MAFK 25.0 8.6 34.2 2500 2MAK 32.1 7.9 24.6 2500 3MAYG 36.0 8.2 22.7 2500 4MAYG (buck) 40.6 8.9 22.0 2500 5MAFH 38.5 9.9 25.8 2500 6MAH 43.8 11.4 26.0 2500
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3.4 Fibre diameter and the prickle effect
3.4.1 Background The problem of prickle of mohair fabric has attracted much attention as far as comfort is concerned. A fabric worn next to skin influences the state of comfort. It may invoke sensations of prickle and itch. These sensations were often mistakenly regarded as an allergy of the skin to mohair, wool, or certain substances. Recent studies in CSIRO [Kenins 1992, Veitch and Naylor 1992, Naylor 1992] have indicated that this is a misconception. Prickle is not an allergenic response of the skin to certain substances. A specific kind of pain nerve is responsible for the prickle sensation. Furthermore, some skin-pain receptors could be activated by forces as small as 75 mgf (mini gram force) exerted at the end of a fibre against the skin. Fibre ends that can support loads of about 75 mgf or more against skin on the fabric surface are the prickle stimuli responsible for the prickle-itch qualities of the sensation.
In 1757, the Swiss mathematician Leonhard Euler published the solution for the buckling of long slender columns. The purpose of this analysis was to determine the minimum axial compressive load for which a column will experience lateral deflections. This is quite similar to the buckling of fibres when the ends of fibres on the surface of the fabric press against the skin.
The critical buckling load is designated by Pcr and has a magnitude of π 3 E D 4 Pcr = 31.36 L2
where Pcr is the Euler buckling load E is the Young’s modulus of the material D is the diameter of the fibre L is the length of the buckling column.
Many research workers have measured Young’s modulus for wool and mohair fibres. The results are not always consistent, as demonstrated by the following examples:
Meredith [1945] Turkish mohair E = 348 cN / tex = 4.55 GPa Hearle [1962] mohair E = 360 gf / tex = 4.61 GPa Watson et al [1966] 64s wool E = 28.8 gf / den = 3.22 GPa mohair E = 40.8 gf / den = 4.71 GPa cashmere E = 36.3 gf / den = 4.19 GPa
11 Final Report Processing Performance and Fabric Properties of Australian Mohair
Smuts et al [1981] wool E = 290 cN / tex = 3.79 GPa mohair E = 407 cN / tex = 5.32 GPa King [1967] mohair E = 308 cN / tex = 4.02 GPa Kawabata [1990] merino wool E = 4.12 GPa = 4.12 GPa 32 µm mohair E = 3.91 GPa = 3.91 GPa 28 µm mohair E = 4.95 GPa = 4.95 GPa Veitch et al [1992] wool E = 3.52 GPa = 3.52 GPa Naylor [1992] wool E = 5.4 GPa = 5.4 GPa
For mohair fibres, Young’s modulus varies from 3.92 to 5.32 GPa according to these different sources. For wool fibres, it varies from 3.22 to 5.40 GPa.
3.4.2 Calculation of critical prickle diameter for mohair fibre
When Pcr = 75 mgf, the results of fibre diameter calculations for different “column” lengths and Young’s modulus values of mohair fibres are listed in Table 8 below.
Table 8 Fibre diameter for Euler buckling simulation of prickle (µm ) E=3.91 4.02 4.55 4.61 4.71 4.95 5.32 GPa L= 1 mm 20.9 20.7 20.1 20.0 19.9 19.7 19.3 2 mm 29.5 29.3 28.4 28.3 28.2 27.8 27.3 3 mm 36.2 35.9 34.8 34.7 34.5 34.1 33.5 4 mm 41.8 41.5 40.2 40.1 39.9 39.4 38.7 5 mm 46.7 46.4 45.0 44.8 44.6 44.0 43.2
Since mohair fibre has a large Young’s modulus, the prickling diameter is about 27-28 µm for a fibre buckling length of 2 mm. However, Table 8 also shows that the longer the fibre length, the greater the prickling diameter. Indeed, it is expected that for protruding length over 5 mm above fabric surface, even 43 µm mohair fibres will not have an appreciable prickle effect on human skin. In addition, when deriving the Euler buckling load, it was assumed that the fibre end was fixed at the base in a strictly mechanical sense. This is not the real case in knitted fabrics or woven fabrics, particularly in loose fabrics. Fibre ends on the surface of the fabrics have some flexibility in movement and this may affect the buckling length to some degree.
Usually, mohair fabrics are not worn next to the skin. If a mohair fabric is going to be worn close or next to the skin, it is strongly recommended that fibres less than 27 µm be used.
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3.5 Mohair top-making
3.5.1 Mohair fibre scouring In this project, scouring of mohair fibres was carried out using a mini laboratory scourer. Fibres were loosely filled in string bags, which allowed impurities to be washed out during scouring. The impurities in mohair were sand, grease, suint and vegetable matters. Scouring would remove most of the impurities except vegetable matter.
A 5-bowl scourer was simulated using the mini laboratory scourer. The scouring process was carried out as summarised in Table 9.
Table 9: Laboratory scouring conditions Detergent Temperature °C Time (Min ) Function Bowl 1 Nil 50 30 Sand, suint removal Bowl 2 200 ml 55 20 Grease removal Bowl 3 150 ml 50 15 Grease removal Bowl 4 Nil 45 30 Rinse Bowl 5 Nil 40 20 Rinse
The detergent used was Lissapol TN450. This is a non-ionic surfactant of the alkylphenol ethoxylate class specifically optimised for natural fibre scouring. Being easily dissolved in hot water or cold water, detergent Lissapol TN450 could be used for neutral or alkaline scouring of raw wool. For greasy wool, the dose suggested was 0.15-0.5 % at a scouring temperature of 60-65 °C. Since mohair fibre contains less grease (1.2-8.0 %) than wool (9.5-27.0 %), a lower dose and lower temperature were used in mohair scouring.
All bags were passed between pressure rollers before entering the next bowl or centrifuge drier in order to remove as much dirty liquid as possible. This operation helped removal of effluent and kept succeeding bowls clean.
It was important that the temperature in all bowls was lower than 55°C in order to retain the lustre of mohair fibres. The water washable impurities in raw mohair were about 1.8-4.2 % of the total weight. These impurities could be washed without the aid of detergent. Therefore no detergent added in bowl 1. It was expected that sand and suint would be washed out and grease remain on the surface of mohair fibres to protect the lustre. The temperature in bowl 1 was lower than that in bowl 2 for the reason of keeping grease from melting and solving.
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It was expected that Grease removal would take place in bowls 2 and 3 after removing most of the mineral impurities in bowl 1. Bowls 4 and 5 were designed to thoroughly rinse the fibres.
A centrifugal drier was used to remove a large amount of water before drying. This reduced the drying time in the oven. When oven temperature was controlled at about 100 °C only 30 minutes was needed for final drying.
3.5.2 Carding Carding is a key operation in top making. An old spinning mill adage goes - well carded is half spun! Carding transforms the randomly arranged fibre assembly into the form of sliver, where fibres are distributed along the axis of the sliver more or less straight and parallel. Since strong mechanical actions are taking place during carding (such as tuft opening, combing of both ends of fibres, transferring fibres from one cylinder to another, doffing etc), it is the main process where the fibres are mechanically damaged. After carding, mean fibre length is decreased and fibre amount shorter than 30 mm will be increased. This means that some long fibres are broken during the carding process.
In order to protect fibres from serious damage caused by strong mechanical action during carding, a lubricant solution should be sprayed on scoured mohair fibres before carding. The lubricant used in our experiment was “Lubricant DM-CONC”. The amount of this lubricant was calculated as 0.8-1.0 % of the weight of mohair fibres being processed. The lubricant solution contained water at 10-16 % of the weight of mohair fibres being processed, since a regain of 18 % gave the best results in spinning wool and mohair fibres.
The lubricant sprayed onto the surface of the fibres would reduce the friction between fibres and between fibres and metal surfaces, thus reducing the possibility of fibre breakage. It was reported that it was fibre-metal lubrication rather than fibre-fibre lubrication that affects fibre breakage in carding. Adding of lubricant solution to the fibres also minimised the generation of static electricity during subsequent operations. The third role played by lubricant solution was to increase the cohesion force between fibres, thus increasing the strength of the sliver – this is particularly important in mohair processing. The lubricant DM-CONC was quite good in all these aspects.
The settings of the carding machine for mohair were, in the main, the same as for processing wool. The only difference was the bigger drafting ratio between the delivery
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speed and the doffer speed for mohair because of the easy slippage between mohair fibres. In our experiment, the delivery speed was increased to 1.35 times normal speed.
3.5.3 Pre-comb Gilling The aim of the gilling operation is to prepare the slivers for combing. Fibres in carded slivers are not straight and parallel. Most of them are entangled and hooked. They are not suitable for combing. Combing carded sliver will result in serious fibre breakage and extremely high noil percentage. Generally in wool processing three gilling operations are needed before combing. One research work reported that only two gilling operations were necessary for mohair fibre because of less fibre entanglement in mohair sliver.
In the experiment, the output of the carding machine was not in the form of sliver but rather in the form of laps. Consequently, it was necessary to have more gilling before combing. Two more gilling operations were added to make the slivers even from laps of different weight. Then three normal gilling operations were followed.
The weight per metre of sliver after the last gilling before combing was 7-10 g/m. It was believed that a lighter sliver would result in better holding of fibres within nippers during combing, and thus reduce the amount of longer fibre being combed into noil.
3.5.4 Combing Combing is a very important operation in top making. It is the main machine that can remove vegetable matter almost completely. It also removes short fibres and neps formed in carding and gilling. Further, the combing operation makes the fibres straight and parallel in combed sliver. However, combed slivers are structurally uneven, and consequently weak in strength.
As expected, combing was the most difficult operation in mohair top processing. The difficulties arose from the smoothness of mohair fibre and the weakness of the combed sliver.
A series of measures were taken to properly set the combing machine. These measures were:
• Increase the tension between feed comb and feed rollers, • Increase the speed of the drawing-off rollers, • Increase the overlapping length of the detached tufts to its maximum, • Increase the tension between calender rollers and delivery rollers,
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• Remove the veil guide on the funnel, • Reduce the machine speed.
In order to reduce the combing speed, a Zener MSC variable motor speed controller was installed. The setting used for combing machine was MSC speed display: 35 Combing speed: 89 nips / min.
The main parameters of the combing machine setting in the experiment were:
• Feed length (feed ratchet 21 teeth) 5.5 mm • Distance between nipper and drawing-off rollers 26 mm • Drawing-off forward movement 188 mm • Drawing-off backward movement 123 mm • Overlapping ratio 65.4 %
The combing process separates fibres of the input slivers into two directions: noil, and combed sliver. In noils there were very short fibres, neps, and vegetable matters. The noil percentage varied depending on the raw material. In one of our experiment with fine kid mohair, the noil held 5.49 %.
The combed sliver was nearly free from vegetable matter and neps. The mean fibre length was increased due to removal of short fibres in the noil. In our experiment with kid mohair, the mean fibre length changed from 75.1 mm before combing to 82.5 mm in the combed sliver. The percentage of fibres shorter than 30 mm was reduced from 17.1 before combing to 8.3 in the combed sliver. Fibres shorter than 30 mm were regarded as a source of irregularity during drafting.
In the worsted system, the task of removing vegetable matter is accomplished by the combing process, whereas in woollen system a chemical process called carbonising is employed.
3.5.5 Post-comb Gilling (top finishing) The combed sliver was very uneven in both thickness and structure since it was made up of detached tufts overlapping with each other. The linkage between neighbouring tufts was weak compare with that between fibres within the same tuft. The distribution of fibre ends was not even. It was expected that most leading ends were concentrated in the fore part of
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the tuft at about the order of feed length. The tail ends of fibres in a tuft were more evenly distributed in longer lengths, which varied depending on the fibre length distribution. Such a sliver has a very strong directional effect when being drafted in a drafting zone. It is recommended that combed sliver should be reversely fed into next drafting machine, which is the situation in normal production. In one experiment to evaluate this recommendation, combed slivers were deliberately fed into the subsequent drafting machine in the wrong direction. It was found that fibres of a tuft were moved collectively and the gap between tufts enlarged, thus causing sliver breakage.
The structural unevenness of combed sliver was composed of two parts: the weak linkage between tufts and the uneven distribution of fibre ends. The latter unevenness would not be noticed if the normal production order is maintained. The first source of unevenness resulted in very weak combed mohair slivers, which caused regular sliver breakage when feeding into next gilling machine. Therefore gilling after combing was necessary to improve top quality. Three gilling operations were used in our experiment.
In factory production, these three gilling operations are used to improve the evenness of the slivers. At the same time, the correct weight of the final top is achieved. Since the mohair top is the final product of a top making factory, a proper type of package is formed for the purpose of easy handling and safe delivery to the yarn spinning factory.
3.6 Mohair yarn spinning
There are five operations in yarn spinning. They are blending, roving, spinning, doubling, twisting, and winding.
3.6.1 Blending process In a worsted spinning factory, the raw material imported to the mill is top. Different tops are to be blended together in order to keep the quality of the final product consistent in colour and composition. Even if tops are of the same colour and the same composition, blending is still needed for achieving consistent production. Blending machines are characterised by a large number of slivers feeding into the machine to get a sufficient mixing effect. In our laboratory there is no special blending machine. Blending effects were achieved by increasing the number of slivers feeding to the machine.
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3.6.2 Roving process The roving process was carried out on a modified flyer combining the drafting part of the Cognetex SRB and the twisting and the winding part of the MS 2 Speed Frame. It can process long staple fibres and give real twist to the roving. The range of the twist inserted is from 20 to 85 t/m with a constant twist change wheel of 14 teeth. The degree of twisting is determined by two factors. One is the strength of the roving, which must be large enough to cope with the pulling force of feeding to the spinning machine. However, too much twist may cause problems in drafting in the spinning operation. Therefore, the second factor is that the roving twist should not affect the smooth drafting required in spinning machine. Consequently, there is a balanced twist range, which makes the roving strong enough and does not disturb the smooth drafting.
3.6.3 Spinning process In the early stage of this work, yarn spinning was carried out on a Hobourn Roberts Ring Spinning Frame. After relocation of the laboratory and consequent loss of floor space, this machine could not be retained. Subsequent yarn spinning was carried out on a small four- spindle spinning machine. Both of these two spinning machines had a double apron drafting system, which is suitable for processing long staple fibres.
3.6.4 Doubling and ply-twisting Typically, the final yarn product from a worsted spinning mill is a two-ply yarn – ie. two single yarns are twisted together to form a ply yarn. For this purpose, two single yarns are wound together onto one package - this operation is called doubling. During doubling, a Uster Yarn Clearer was installed to monitor and clear the single yarns (ie. cut out the thick and thin places) to make the ply-yarn more even and fault free.
For ply-twisting in this project, a Universal Ring Twisting Frame was used. For all mohair yarns processed (ie. for all blend ratios and yarn counts), the ply-twisting operation was smooth and trouble-free. Indeed, after formation of the mohair yarns, all subsequent processes were similarly smooth and trouble-free.
3.6.5 Winding The final operation of yarn spinning is winding. During winding, ply-yarns are wound onto cones that are suitable for easy unwinding in knitting or weaving (ie. subsequent fabric formation processes).
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4. SOLUTION TO PROCESSING PROBLEMS
4.1 Combing machine adjustment
As explained in Section 3.5.4, combing was a particularly difficult process during mohair processing, and a number of measures were taken in this research to solve the problems. Among other things, combing speed was reduced. A Zener MSC variable motor speed controller was installed to control the comb speed for this research. The actual speed used was 89 nips/min. During adjustment of the combing machine to process pure mohair slivers, especially slivers made up of adult hair mohair fibres, it was found that the gap between sword and leather apron was crucial and very sensitive for mohair processing. It was also observed that the mohair tuft just detached from nipper was not able to move backwards with the movement of the leather apron which carried them. The sword stopped the movement of the tuft and fibres in the tuft were accumulated, curled, and deformed in the area between the detaching rollers and the sword. A very poor quality of fibre lap was obtained in subsequent withdrawing and overlapping of tufts. It was initially thought that the gap between sword and leather was too small so that fibres carried by the leather apron were stopped by the sword from moving with it. This idea was proved to be wrong when the gap was increased and the situation was not improved but worsened.
The function of the sword S is to beat down the tail of the drawn-off tuft in order to facilitate the overlapping operation with the incoming tuft and not hinder it in the combing cycle. In addition the sword also completes the drawing-off operation when long fibres were being combed. The counter sword CS working with the sword acts as a support for the tails during the down stroke of the sword S. The position of the sword in relation to the leather apron was found to be crucial. The proper setting should be such that the sword slightly grazed the leather apron and a 0.2 mm thick feeler gauge could be passed through the gap.
The three objects involved in this setting are the sword, the fibre tufts and the leather apron. With the correct machine setting, the sword was lightly pushing the tufts against the leather apron. Frictional forces would be generated between the sword and the tufts, between the mohair fibres in the tufts, and between the tufts and the leather apron. The interaction of these frictional forces determines the behaviour of the tufts. It seems that under the pressure determined by the gap setting, the friction between the leather apron and mohair fibres was larger than the friction between the mohair fibres and the surface of the metal sword. Thus, mohair fibres would move back with the movement of leather apron as a fibre assembly
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(tuft). On other hand, mohair fibres are also moving on the metal surface of the sword. In this way mohair fibres were kept in good order in the detached tufts, thus creating good conditions for high quality overlapping.
After correctly setting the sword, there was tremendous improvement in the overlapping process and the quality of the combed sliver. Thus the strength of combed sliver was increased and the speed of the combing machine can be raised.
4.2 Improving sliver strength
4.2.1 Background As mentioned previously, the lack of cohesion and the coarseness of mohair fibre lead to very weak mohair slivers. Such slivers result in breaking and uncontrolled drafting when feeding into the next processing machine and cause difficulty in sliver handling and transportation. Veldsman [1970] gave a good account of the special problems derived from the smooth surface of mohair fibres, especially in the preparatory stage immediately after combing.
There have been several approaches to the problem of handling weak slivers and two techniques are currently favoured.
One is to select lubricants and apply these at the appropriate stage to allow sufficient control of the fires during carding, combing and spinning. Slinger and Robinson [1968] sprayed mohair top during the first gilling operation with two appropriate commercial additives and water. Cilliers [1968] investigated the processing on the continental (French) system, including the effects of different additives and regains. He concluded that special additives need to be applied, usually in the form of a fine spray, in order to overcome the lack of fibre cohesion and thus improve the inter-fibre cohesion. Turpie, Kruger and Hunter [1972] also studied the lubrication of mohair and found that a withdrawal force of the order of 37.2 N/g gave the best overall spinning performance. When mohair is spun on the French Worsted System, the use of lubricants and additives at the optimum level is essential.
The second technique is the use of a ‘Sliver Transport System’, where the sliver is supported to minimise any tension. This is typified in the approach taken by Süessen with its Ringcan system, the essential component of which is a method of transporting the slivers from the can to the drafting unit. Some carding machine makers also used this approach to
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assist the initial stages of transfer of the web from the doffer to the coiler. The use of special cans with false bottoms supported by compressible springs to assist the passage of slivers from cans may also be referred to this approach. The obvious disadvantage of this approach is that it requires complicated new components and units. So far, and to our knowledge, it has not been successfully applied to the mohair processing industry.
4.2.2 The sliver twister The approach adopted in this research was to apply twist onto the sliver to keep fibres closely pushed together, thereby increasing the friction and cohesion force between fibres. In fact, the twist applied not only strengthened the sliver to avoid breakage during feeding and delivery but also minimised uncontrolled drafting that causes unevenness of slivers and yarns in subsequent processing. The relationship between strength and twist can be seen from following experiment.
The mohair fibre used was the thickest mohair fibre, MAH. The thickness of the combed sliver tested was 5.8 g/m. If no twist was applied to the combed sliver, it had no strength at all and could not be pulled out from the can. When 5.8 t/m of twist was applied onto the combed sliver, the strength of the sliver was 15.4 g. Instead of using absolute value of strength, a breaking length can be calculated, viz.
Breaking length (m) = Sliver Breaking Strength / Sliver Weight Per Metre
Taking half-metre lengths of combed sliver as samples, strengths were measured using the Instron Universal Testing Instrument model 1122. Results are summarised in Table 10.
Table 10: Effect of twist on mohair sliver strength & breaking length Twist t/m Average strength g Average break length m Range m 5.8 15.4 2.7 2.3 – 2.8 7.8 26.9 4.6 3.8 – 5.3 9.8 32.3 5.6 4.0 – 6.6
It can be seen that when a small amount of twist was applied to this very weak sliver, the strength of the sliver was greatly increased. The combed sliver without twist could not withstand any tension at all. Indeed, it could not even be pulled out of the sliver can without breakage. After a twist of 5.8 t/m was applied to the sliver it could stand at least 2.3 metres of its own weight. A sliver with such strength (or breaking length) will have no problem in processing.
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From these results it has been concluded that twist is the best means to strengthen weak slivers.
4.2.3 Construction and use of the sliver twister The Sliver Twister is a simple unit designed and manufactured specially for this project. It consists of a FHP Parajust Speed Controller, motor and a rotating plate on which the sliver can sits. Figure 2 shows a schematic diagram of the Sliver Twister. The rotating direction and the speed of the plate is adjustable to allow an appropriate amount of twist to be applied to the sliver. The speed of the sliver twister ranges from 0.2 rpm to over 200 rpm and covers the twist range for many applications.
Variable speed rotating platform (for the sliver can)
Motor
Fig. 2: The sliver twister
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There are two ways of using the Sliver Twister. One is to put the Sliver Twister on the output side of the machine. It applies twist onto the delivered twistless sliver as it enters the can. The Sliver Twister can also be placed on input side of the machine so that it will apply twist onto the input twistless sliver. The speed of the Twister is determined by the amount of the twist to be applied and the sliver speed.
In our experiment, the Sliver Twister was used to strengthen the combed mohair sliver. The results were very encouraging – indeed, exciting. Without twist, combed slivers were so weak that they could not even be pulled out from the can. After using the Sliver Twister, combed slivers had real twist and were greatly strengthened. The fibres in the twisted combed slivers were kept in good order without uncontrolled drafting and deformation during subsequent operations. When being fed into the next gilling machine, these combed slivers could successfully cope with the frictional forces along their passage and the various tensions experience, without breakage.
4.3 Reducing Yarn Hairiness
4.3.1 Introduction Yarn hairiness is a rather complex property and its measurement needs special instrumentation. Zweigle, Uster and Shirley Development Limted (SDL) have produced commercial hairiness meters, and reducing yarn hairiness has been a major research effort in recent years by machine manufacturers such as Suessen and Rieter.
The hairiness of mohair yarn is very interesting. In some cases, such as hand-knitted women’s cardigans, shawls and blankets, hairiness is a desired property enhancing the handle and appearance of the fabric. In other cases, however, such as for men’s worsted suiting, hairiness is a disadvantage and has to be minimised.
Mohair is inclined to produce a more hairy yarn than wool. Ways of increasing and reducing the hairiness of mohair yarn have been research topics for decades. The first topic (increasing hairiness) was associated with the works on brushing of mohair yarns and fabrics. The second topic was related to fundamental works on various factors influencing yarn hairiness, such as fibre properties, yarn parameters, yarn spinning processes and processes subsequent to the spinning in fabric formation and finishing.
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To date, little has been published on direct and effective ways to control the hairiness of yarn in spinning. Pillay [1964], Partharasarathy [1966], Criter [1961] and Lunenschloss [1967] studied the influence of condensers on the hairiness of the yarn. They concluded that yarns produced with condensers in the drafting field are less hairy than those spun without the use of condensers. Kalyanarman [1992] suggested a method of inserting an air pressure column between the front roller and lappet and allowing the yarn to pass through this column. It was claimed that the hairiness in a yarn could be considerably reduced. Wang et al [1997] used an air nozzle in both spinning and winding processes to effectively reduce yarn hairiness.
Hairiness occurs because some fibre ends protrude from the yarn body while others arch into loops emerging from the yarn. Beralla [1956] found that the number of protruding ends was appreciably the same as the number of fibres in the cross section of the yarn. Pillay [1964] used tracer fibres to examine Beralla’s conclusions. He demonstrated the existence of a high correlation (0.78) between the number of protruding ends and the number of fibres in the cross section and found the number of fibres in the section that emerged and projected one end out of the yarn to be 31%. Of the protruding ends, about 55% corresponded to fibre tails.
Yarn hairiness depends on the fibres in the outer layer of the yarn that do not directly adhere to the core. Some of these fibres have an end in the core of the yarn gripped by other fibres, whereas others, because of the mechanical properties of the fibre (rigidity, shape, etc) emerge to the surface. During the twisting of yarn, other fibres are further displaced from their central position to the yarn surface, with their ends being nipped in the core.
Beralla [1956, 1957] found that the length of the protruding ends was distributed according to an exponential law. This exponential or near exponential distribution has been confirmed by many other workers. Wang [1997, 1998] has also examined the factors that affect yarn hairiness results obtained on commercial hairiness meters.
4.3.2 Reducing the hairiness of mohair yarns The following experiments were carried out using mohair roving of MAFH fleece. Two rovings of 468 tex were fed to the spinning machine to produce yarn with a count of 18 tex and twist of 363 t/m. Spinning was carried out on Toenniessen Ring Spinner which is a six spindle laboratory worsted spinning machine with a double apron drafting system. The machine was run at spindle speed of 7,000 rpm.
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Normal mohair yarn was spun for comparison with experimental yarns produced using three hairiness reducing techniques: the use of a condenser in drafting zone, of an air-jet between the front roller and the lappet, and filament wrapping. All yarns were spun on the same spindle to eliminate the possibility of differences between spindles.
All yarns were tested on Zweigle G565 Hairiness Meter. The S3 value given by this instrument indicates the total number of hairs of 3mm and longer. Hairiness shorter than 3 mm has no significant effect in practice. Sample length measured was 500 meters. A hairiness index was calculated by the instrument for reference. The results are summarised in Table 11.
Table 11: Results of hairiness tests for various mohair yarns Yarn Normal Condenser Air-jet Filament Index 130 183 116 39 S3 73850 73966 68816 27244 1 85702 83358 83129 66942 2 34456 32912 33661 19896 3 19968 18956 18674 9430 4 22732 21241 20283 8799 6 12429 12661 11488 3930 8 7973 8344 7333 2118 10 4758 5127 4489 1249 12 3605 4251 3700 943 15 1464 1974 1635 438 18 610 941 799 208 21 231 347 341 101 25 82 124 76 28
1) Condenser The condenser was put in the drafting zone just before the front rollers. The width of channel was 2.8 mm. It was thought that fibres passing through the narrow channel of the condenser could result in a concentration of fibres in the yarn, thus reducing hairiness. However, in our experiment the hairiness of the yarn was increased. This is contrary to the results published by other researchers. This may be due to the bending rigidity of mohair fibres – bending rigidity is a function of fibre diameter to the 4th power – encouraging a “spring-back” effect when the fibres are released from channel of the condenser.
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2) Air-jet An air-jet was placed between the front roller and the lappet (Figure 3). The distance between the jet and the lappet was 45 mm, and the distance between the front roller to the lappet was 215 mm. The height of jet was 25 mm. The air pressure was maintained at 0.4 bar. Whilst there was an air current blowing upwards which helped piecing when the yarn end broke, there was also a current blowing towards the nip of front rollers, where fibres emerged, which disturbed the fibre flow and caused more fibre fly. Nevertheless, as indicated in Table 11, there was some degree of reduction in hairiness.
Apron
Lappet Front Rollers Air Jet
Fig. 3: Hair reduction using an air nozzle
3) Filament wrapping As indicated in Figure 4, this method used is quite easy to adopt for any spinning machine, without the need of significant machine modification. The filament yarn was obtained from Dupont – a twistless multifilament yarn composed of six nylon filaments of 3-denier diameter. As Table 11 shows, the results obtained are very promising. Indeed, the hairiness of mohair yarn was dramatically reduced. Taking the hairiness of normal yarn as a standard (100%) for comparison, the reduction in the number of hairs of 1 mm, 2 mm, and 3 mm lengths and above is shown in Table 12 below.
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Table 12: Comparison of hairiness of mohair yarns – normal and filament wrapped 1 mm 2 mm 3 mm and above Normal yarn 85702 100% 34456 100% 73850 100% Filament wrap 66942 78% 19896 58% 27244 37%
Clearly, filament wrapping was extremely effective in reducing hairiness in 1mm, 2mm, and 3 mm and longer hairs. It is well known that longer hairs can be more harmful in later processing, especially in weaving sector when used as warp yarns. The longer the hair, the more effective is the filament wrapping method. Nearly two-thirds of the hairs of length 3mm and longer have been suppressed.
Filament
Front rollers Back rollers
Apron
Filament Wrapping
Mohair yarn
Fig. 4: Reducing yarn hairiness with filament wrapping
The wrapping process can be seen in Figure 5 from the four consecutive pictures captured by video camera. It has also been observed from video observation that most protruding ends were the leading ends of mohair fibres. This phenomenon is contrary to other observer’s findings, which claim that about 55 % of hairs corresponded to fibre tails. By carefully watching the video film, this phenomenon can be explained as being due to fibre stiffness and the poor cohesion between fibres, with the leading ends of mohair fibres tending to depart from main fibre stream when they left the front rollers. Some of these fibres were recaptured into the main stream by their trailing length and some flew away as
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fibre fly. The former case yields a leading fibre protruding end on the yarn. The later case explains the fibre loss during mohair spinning. In this sense, mohair spinning was far from perfect and more work needs to be done in the future.
1 2
3 4
Legends: 1 shows a hairy part of yarn coming, 2 shows the hairy part closer to wrapping point, 3 shows hairy part being wrapped in, 4 shows this wrapping process finished.
Figure 5: Photos showing the hair wrapping process
While filament wrapping is the most effective and simple way to solve the hairiness problem of mohair yarn spinning, it does raise other questions related to the purity of mohair yarn. In particular, to what degree will the synthetic filament affect the characteristics of the mohair fabric?
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4.4 Producing Low and Twistless Mohair Yarns
4.4.1 The advantages of low and twistless mohair yarns Twist is very important in yarn spinning. It gives yarn sufficient strength for smooth and efficient processing. It also gives the final product sufficient strength for various end-uses. However, excessive amount of twist has the disadvantage of imparting a harsh handle to a fabric. For good fabric handle, twistless and low twist yarns are generally preferred. A twistless yarn of conventional type has no strength. Once it has been assembled into a suitable structured fabric, the compacting forces created by the fabric structure itself would be sufficient to hold the system together. Hence it is possible for weft yarns in a fabric to be twistless or of low twist.
Twistless and low twist yarns have the following outstanding characteristics:
• Increased bulkiness of the yarn gives fabrics a better cover. • Fabrics can have a very soft handle. • Fabrics are highly absorbent, giving improved depth of colour in dyeing. • Fabric lustre may be enhanced due to the parallel arrangement of fibres. • The low torque yarns eliminates stitch distortion in knotted fabrics.
4.4.2 Traditional manufacturing of twistless yarns In twistless yarn spinning, the fibres in a strand may be held together by an adhesive or filament wrapping, instead of by twist. Some processes have been developed in this area. They are:
• Tek-ja process (adhesive method) developed by Fiberbond Laboratories Inc. This was the first twistless spinning process to achieve practical success. • TNO process (starch method) developed by the Applied Scientific Fibres Research Institute was another example of twistless spinning. • The Pavena system (bonding method) was introduced by Rieter of Switzerland. • The Bobtex ICS system (molten method) incorporates three components together: a continuous filament carrier in the core; extruded molten polymer; staple fibres • The Periloc process (felting method) developed by the International Wool Secretariat is based on the felting properties of wool. • Wrap-spun yarn (wrapping method) is produced on hollow spindle system.
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4.4.3 Low-twist composite mohair yarns If a filament is combined in spinning into an otherwise 100% mohair yarn, a composite mohair yarn would be obtained. Such composite mohair yarn has several advantages over conventional yarn. One of these is that it lowers the minimum number of fibres per yarn cross section necessary for successful spinning. This means that it creates the possibility of spinning finer mohair yarns. Due to the coarseness of mohair fibre, it was impossible to spin yarns finer than 30 tex using conventional processes. With composite yarn technology, it is possible to spin yarns of 20 tex and even finer.
Spinning of composite yarn can be carried out on conventional ring frame with minor modifications. The spinning arrangement is schematically shown in Figure 6 below.
Filament
Roving Guide with tensioner
Front roller
Composite yarn
Fig. 6: Producing composite yarn on a ring frame
Filament yarn is fed directly to the front nip through a guide without passing through the drafting zone of the ring frame. At this position, the drafted staple fibre strand combined with the filaments are twisted together to form a composite yarn.
In composite yarn spinning, due to the high strength of the filament, the composite yarn doesn’t break completely if the end goes “down”. Only the staple fibre component in the composite yarn breaks. However, the filament part of the composite yarn in the twisting area cannot itself propagate twist to the nip of the front rollers to pick up staple fibres into the composite yarn.
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It is also interesting to note that the minimum twist needed for composite yarn spinning is not decided by the yarn strength required to cope with the spinning tension, but rather by the torque demanded for transmitting twist to the nip of the front rollers. The twist needed for this purpose in composite yarn spinning is less than that for conventional yarn spinning. Therefore, the twist of a composite yarn can be lower than that of a conventional yarn of same count.
The filament yarn used in our project was from Du Pont. It consisted of five nylon filaments of 3 denier each in textured form. With this filament yarn, a single mohair composite yarn of 20 tex has been successfully spun – ie. a “blend” of 92% mohair with 8% nylon.
4.4.4 The 3-in-1 process of making twistless yarn As discussed above, twistless yarns have attractive properties. The spinning of low twist or twistless mohair yarn is more appealing because mohair fibre has smooth lustrous surface. However, as mentioned before, manufacturing of twistless yarn needs special equipment. Can we spin a twistless yarn on a conventional ring spinning machine? Our experiment has provided a positive answer.
Processing consists of two steps. Firstly, spinning of a composite mohair yarn is carried out on a conventional ring-spinning machine with minor modifications. A 15-denier nylon filament yarn is fed directly to the nip of the front rollers through a guide. After the nip, twist is applied to form a composite yarn. The amount of twist needed for smooth spinning is less than the conventional level due to the presence of the filament yarn.
After spinning the single composite yarn, it is possible to reduce the twist further if an opposite twist is applied to yarn. This is the second stage of the process – this opposite twist will be called de-twist, and the process called de-twisting. If the amount of de-twist is less than the amount of spinning twist, the resulting composite yarn is of low twist. If the same amount of de-twist as spinning twist is applied it is possible to get a twistless composite yarn. The resulting composite yarn has a twistless mohair fibre core wrapped with nylon filament yarn.
The de-twisted single mohair composite yarns can be doubled in winding. Then, on a twisting machine, they can be processed into folded yarn as usual. For greater efficiency and reduced material handling, a “three operations into one” method of processing plied mohair yarn has been developed. As the name implies, it combines de-twisting, doubling and ply-twisting into one process.
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De-twisting will weaken the strip resistance of single composite yarn when handled in doubling and ply twisting. Once processed into a folded composite yarn, it becomes quite strong and will have no problem in further processing. Therefore, the weakest stage of composite yarn processing is immediately after the opposite twist (de-twist) has been applied to the single composite yarn.
Using a conventional ring frame, a novel method has been devised to combine de-twisting, doubling and ply-twisting into one operation. The new processing method is illustrated in Figure 7 below. This not only saves labour but also improves the quality of the plied composite yarn since it minimises the risk of deforming the single composite yarn in its weakest state (eg. in subsequent transportation and handling).
Front roller Front roller
Doubling
Ply-twisting Opposite twisting
S Twi st S Twi st
Figure 7: The 3-in-1 process
After spinning of single composite yarns, the “three operations into one” processing method was used to produce the two-fold yarn. The opposite twist (de-twist) was the same as ply twist. Although in our spinning machine it was possible to have different twisting levels on two sides, we had to have the twisting levels equal in order to keep the speed of front rollers on both sides identical. Otherwise there would be a drafting between the front rollers of the two sides.
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A series of plied composite yarns of low twist have been successfully spun. For example, a mohair composite yarn of 2 x 20 tex was spun having single twist of 309 t/m and ply twist of 255 t/m. In conventional spinning, it was impossible to get such a fine mohair yarn with such a low twist level.
Using the same single process, a twistless single composite yarn can be produced, if the amount of de-twist is equal to the amount of spinning twist, and then immediately plied into a two-ply yarn. We have also successfully made such very soft mohair yarns.
So far the research emphasis has been on fibre to yarn. This is quite justifiable considering that developing new fabrics/products often means developing new yarns and even new fibres. The following sections report the fabric work of this research project.
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5. MOHAIR KNITTED FABRICS
5.1 Traditional products
Mohair fibres have been widely used in knitting products to great advantage, particularly by imparting a soft handle, lustrous and bright colour, and a fluffy appearance. Knitwear traditionally held some 80 % of mohair’s outlets. Among them, large quantities have been used in ladies sweaters with a traditional brushed and highly lustrous look.
The yarns used for conventional brushed mohair knitwear are quite coarse, usually in the range of 2 to 12 Nm (ie. 500 to 83 tex, respectively) and upwards. The heavy fabrics made from these yarns are mainly for cold weather climates.
5.2 Development trends
The consumer preference has been changing in recent years. The key customer requirements now are: trans-seasonal, lighter weight, washability, a better price to quality ratio, and a relaxed and comfortable styling. Hence, the traditional image of brushed mohair for knitwear is considered to be old-fashioned and in need of updating.
It is believed that further developments should be made to change the appearance of this traditional look. Using unbrushed qualities is certainly a direction but it is still far from meeting the requirements of consumers. With growing focus on comfort, light-weight, and trans-seasonal properties, spinning finer and softer mohair yarns has become a matter of priority. The latter has been the focus of the spinning developments discussed earlier in this report.
To have a light-weight and soft fabric means finer yarns and looser fabric structures. The limitation of spinning finer mohair yarns is due to the coarseness of mohair fibre. For 28 µm mohair fibres, it has been calculated that the finest mohair yarn is about 36 tex. The effort on spinning research in this report has concentrated on a new way to spin mohair yarns far below this traditional limit of yarn count. The resulting yarns will have the benefits of being ideally balanced, softer and lighter.
In pursuing an ultra soft touch (or handle) of fabric, mohair fibre has the advantage of a very smooth fibre surface. This advantage will be enhanced by applying lower twist on the yarns and carefully selecting the structure of the fabrics. Trends indicate a growing belief
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that the new jerseys will be used more and more to replace woven fabrics, because in many instances jerseys are starting to resemble woven structures, but with a more supple handle. The fluid and smooth handle of brushed mohair fabrics nevertheless still attracts attention.
Mohair fibre is usually blended with natural fibres such as wool, alpaca, silk, cotton and linen. To meet today’s standard of ‘easy care’ criteria and price sensitivity, mohair fibre blended with viscose, nylon, acrylic and polyester is also gaining popularity.
5.3 Spinning of mohair knitting yarns
During this research project, several knitting yarns have been processed. Some of them were conventional yarns while others were yarns spun as reported in Section 4.
In practice, yarns are spun for a certain purpose. To meet the requirements of the final product, the fibre raw materials are chosen, or composition of blends are designed, and the spinning process is planned, including various parameters of machine settings. Twist levels of single yarn and ply yarn are decided. For example, if a soft handle and light fabric is to be produced, finer fibres may be used, low twist may be inserted into the yarn, and finer yarns may be spun. To get the final product right, spinning of the right yarn provides a base for further processing. The subsequent fabric forming and fabric finishing processes also have great role to play.
In this research work, a certain material has been chosen and spun into different counts of yarn, then these yarns were used to make knitted fabrics to examine the effect of yarn type on fabric appearance and handle.
A list of yarns processed through to knitted fabrics is given in Appendix 1. The yarns were spun from very coarse hair mohair fibre to the most fine mohair fibre – fine kid mohair.
5.4 Mohair knitted fabrics
Sixteen (16) fabrics were knitted from hair, fine hair, and fine kid mohair yarns. All knitting performed on a Dubied Hand Knitting machine of gauge 10. Plain and rib structures were chosen for the fabric. The aim was to have a general investigation of the appearance and handle of weft-knitted fabrics made from coarse and fine mohair fibres, to know what the
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potential is for these fibres. Consequently, the fabric samples are in no way recommended or optimised for commercial exploitation.
All knitted fabrics were compiled into four sample books that accompanied the third milestone report for this project in 1997.
In fabric sample book “Hair Mohair 1”, there were four fabrics loosely knitted from the coarser yarns of 50 tex and over. Due to the low yarn twist and loose knitted structure, it was found that the handle of these samples was not as bad as expected. In fact, the fabrics made of fine hair mohair were quite soft and had a nice handle.
In sample book “Hair Mohair 2”, another four fabrics knitted from fine yarns were presented. There were two different styles. One was of fine soft handle and the other was pursuing a cool and crisp feeling (handle). The latter style resembled linen fabric. After careful design and optimisation, these fabrics may be very good for summer and tropical use, but prickle may be a problem if worn next to skin.
In fabric sample book “Kid Mohair 1”, three fabrics were made from 50 tex two plied yarns. One of these was made from twistless single yarn (de-twist = single yarn twist). Two loosely knitted fabrics were very soft in handle and resembled cashmere fabrics.
In fabric sample “Kid Mohair 2”, the fabrics were made of finer yarns from 20 tex to 25 tex. These yarns were made possible only with the innovative spinning technology such as the 3-in-1 process reported in Section 4. These fabrics were fine, soft and lightweight. It seems that fine kid mohair blended with some wool or other fine fibres may be worn close to skin.
5.5 Knitted sample fabrics for the final report
Special yarns and special fabrics were also manufactured for this final report. Since the spinning laboratory no longer has the Hobourn Roberts Ring Spinning Frame, where “three- in-one” process was implemented, we were not able to spin twistless and low twist mohair yarns for this final report. A series of normal yarns of different yarn count were spun, viz. 80 tex x 2, 60 tex x 2, 50 tex x 2, 40 tex x 2, 30 tex x 2 and 20 tex x 2. Among this group, only the yarn of 20 tex was spun with a 15-denier filament as core – details concerning these yarns are presented in Appendix 2. Six single fabrics were knitted and the samples are attached to this report in a separate sample book.
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6. MOHAIR WOVEN FABRICS
Two woven fabric trials were undertaken in this project. The first was a preliminary investigation undertaken in our laboratories and reported in the 1997 milestone report. The second was undertaken with industry collaboration and forms the main content of this section.
6.1 Mohair fabrics with different wool composition
Five mohair and wool yarns of various compositions were spun. The compositions were
• 100 % wool • 80 % wool + 20 % mohair • 50 % wool + 50 % mohair • 20 % wool + 80 % mohair • 100 % mohair
The aim was to investigate the effect of mohair composition on the performance of woven fabric. Therefore, weaving loom conditions were kept constant for all fabrics. The characteristics of the mohair and wool fibres and of the blend compositions are summarised in Table 13.
Table 13: Fibre characteristics of wool, mohair and their blends Blend ratio Length Fineness Mean mm CV % Mean mm CV % 100 % mohair 82.5 47.1 23.72 30.2 20 % wool 80 % mohair 79.4 47.2 23.46 28.9 50 % wool 50 % mohair 74.9 46.3 23.07 26.7 80 % wool 20 % mohair 70.3 44.3 22.67 24.2 100 % wool 67.2 42.0 22.41 22.0
The blending method was sliver blending as this was easier to perform. All yarns were spun to 40 tex in single count. Two single yarns were plied together to form the final two-ply yarns. The single yarn twist was 440 t/m of Z direction and the ply twist was 293 t/m.
In fabric development, the warp yarns were wool yarns on the Sulzer loom. Loom set up was the same for all fabrics, viz.
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Total number of warp ends 2770 Reed density of dents 22 / inch = 8.66 / cm Ends per dent 2 Fabric width in reed 160 cm Warp sett 44 / inch = 17.3 / cm Average warp count 68 tex Weft sett 28 / inch = 11 / cm Weft yarn count 80 tex Weave structure 2 / 2 Z-Twill
About four square metres of fabric with each weft yarn was produced. Ms E. Koo, a final- year student of the Department, tested all five fabrics. The detailed test results were covered in her thesis “A Study of Wool-Mohair Fabric Development”.
In summary, Ms Koo concluded that overall the mohair blend fabrics were thinner, lighter in areal density and had less weave crimp. Mechanical testing indicated that the mohair fabrics were easier to shear and compress but hard to bend and extend. In addition mohair fabrics required less energy to recover from compression, bending, shear and tensile extension. Finally, mohair fabric tended to be less stable in dimensional stability.
6.2 Processing of two mohair worsted fabrics in industry
The following experiments were carried out with the cooperation of a worsted mill, using mohair yarns produced from this research. This mill produces three million metres of worsted fabric annually. It has spinning, weaving, dyeing and finishing departments.
Two fabric products were chosen, one was tropical suiting fabric and the other was Gongskin, which is a fabric of high warp density and sateen structure. The two fabrics had different dyeing methods, with yarn dyeing for the tropical suiting fabric and piece dyeing for Gongskin. The weaving and finishing conditions were the same as used for corresponding wool fabrics. In fact, the mohair fabrics were processed in the same lot with wool fabrics, undergoing same weaving and finishing conditions. It was therefore decided that samples of wool fabrics would be taken at the same time as our mohair samples, thus allowing comparison of these wool fabric samples with the performance of the mohair fabrics. Fabric samples are attached to this report in a separate sample book.
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Mohair tropical suiting
Warp yarn: 60 Nm / 2 96% Australian wool 66s 4% 3 denier polyester
Weft yarn: 40 Nm single 100 % fine kid mohair with 15 denier nylon filament
Loom conditions: Width 173.5 cm Warp density 208 / 10 cm Weft density 213 / 10 cm Fabric structure 1 / 1 plain Weight of the fabric from loom 257 g / m
Dyeing: Warp yarn Top dyeing Weft single mohair yarn Yarn dyeing
Fabric finishing:
• Singeing v = 85 m / min. once Singeing entails burning off the fibre ends on the fabric surface to get a clear, smooth surface.
• Scouring 40º C x 60 min, Fabrics were scoured in open-width form. This ensures that creases and wrinkles were minimised, and would be easier to be removed subsequently. Scouring removed oil marks and various impurities to make the fabric clean. It also improved the style and handle of the fabric. Temperature and time were two factors monitored.
• Rinse 40º C x 60 min.
• Crabbing T = 65 º C Crabbing is a finishing process designed to set the fabric permanently. The fabric was immersed in hot water and then into cold water. Crabbing reduced the amount of shrinkage in mohair fabrics.
• Decatizing v = 15 m / min, T = 130º C, P = 120 b.
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Decatizing is a process used to improve surface smoothness and lustre, and to develop a permanent sheen on fabric surface. The process involves temperature, pressure and moisture. In this process, hot steam and cold air were forced through the fabric which was under high pressure.
• Drying T = 110 º C, v = 14 m /min
• Inspection, including perching, burling and mending
• Brushing Face twice, reverse once Brushing removed short, loose fibre ends from the surface of the fabric, yielding a smooth and uniform appearance.
• Shearing v = 10 m / min, gap = thickness of two papers, face side twice, reverse twice. Shearing involved cutting off undesirable surface fibres or yarns that extend beyond the length desired. After singeing and subsequent processing, fibre ends or loose fibres may protrude from the fabric surface. Shearing cuts off these ends and creates a clear smooth fabric.
• Damping Twice, time interval 4 hours, Regain = 14 – 16 %
• Decatizing Steaming 10 min, cold air 10 min, Pressure 0.2 MPa
• Damping Twice with time interval of 4 hours, Regain = 14 – 16 %
• Electrical setting Pressure 25 MPa, T = 40º C
• Decatizing Steaming 10 min, cold air 10 min, Pressure 0.2 MPa.
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Mohair Gongskin
Warp yarn: 58 Nm / 2 100 % Australian wool 20.6 –21.5 µm
Weft yarn: 40 Nm single 100 % fine kid mohair with 15 denier nylon filament
Loom conditions: Width 172.4 cm Warp density 426 / 10 cm Weft density 247 / 10 cm Fabric structure 2 / 5 warp sateen Weight of the fabric from loom 428 g / m
Finishing conditions:
• Piece dyeing • Singeing v = 85 m / min once • Scouring 40º C x 60 min • Rinse 40º C x 30 min • Double crabbing 40º C x 6 times • Piece dying • Drying T = 110º C, v = 14 m / min • Brushing Face twice, reverse once • Shearing v = 10 m / min, gap = thickness of two papers, face twice, reverse once • Decatizing Steaming 10 min, cold air 10 min, pressure 0.2 MPa
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6.3 Test results for worsted mohair and wool fabrics
Traditionally, fabric quality is manually assessed through fabric handle (or hand), especially for apparel fabrics. However, such handle assessment is subjective, based on one’s perception of the fabric through the sense of touch. Ideally, there should be a standard for common evaluation (by direct fabric comparison) for handle. Such standards have been developed by the Textile Machinery Society of Japan: the Standard for Men’s Suit Fabric comprises sets of standard fabric samples used to evaluate a fabric’s handle attributes of (a) stiffness, smoothness and fullness for winter fabrics, and (b) stiffness, crispness, fullness & softness and anti-drape stiffness for summer fabrics. It should be noted that these standards apply to Japanese preferences and do not fully translate into other cultures. Further, individual perceptions made definitive handle assessment difficult. The last two decades have witnessed the development of fabric objective technology. This is due to the scientific recognition that fabric handle is related to the low stress mechanical properties (in bending, tension, shear and lateral compression) and surface properties (friction and roughness) of a fabric and the availability of suitable instrumentation to measure these properties. Further, these properties have been identified with fabric tailorability performance and have been used in fabric design for functional performance and in production control in textile and garment manufacture.
6.3.1 Fabric testing instruments There are two instrumentation systems for fabric objective measurement technology. They are the FAST and KESF systems. FAST (Fabric Assurance by Simple Testing) is a simple system for the assessment of fabric properties and consists of three instruments: FAST-1 Compression Meter FAST-2 Bending Meter FAST-3 Extension Meter The FAST instruments were developed by CSIRO in 1980’s. These instruments are simpler to use and straight-forward for direct application in industry.
The KESF (Kawabata Evaluation System for Fabrics) system provides a greater depth of data, including surface properties, and is generally considered more complicated to use but also more suitable for research purposes. It comprises four separate instruments: KES-FB1 Tensile and Shear Tester KES-FB2 Pure Bending Tester KES-FB3 Compression Tester KES-FB4 Surface Tester
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Both systems were used in this experiment for measuring mechanical and surface properties of mohair fabrics. In addition, fabric areal density was also measured using standard techniques. Full results for each series of tests are reported in Appendix 3. The quantity of data generated and its interpretation requires more in-depth knowledge of processing conditions and fabric construction parameters than is currently available. The following discussion therefore highlights only some aspects of the data.
6.3.2 Fabric weight measurement Table 14 summarises the areal density values of the four fabrics. As can be seen in this table, our mohair tropical suiting fabric was very light and thin, with the mass per square metre (gsm) being 151.8 g only. In comparison, the tropical wool suiting fabric was approximately 10 g higher in areal density. Our mohair Gongskin was heavier, with a gsm of 277.4, since the fabric has a high warp density. In comparison, the wool Gongskin fabric was approximately 13.5 g higher in areal density.
Table 14: Fabric areal density (gsm) Fabric Mean areal density (g/m²)
Mohair Tropical Suiting 151.8
Wool Tropical Suiting 161.6
Mohair Gongskin 277.4
Wool Gongskin 290.8
6.3.3 Compression property of mohair fabrics Textile materials are highly compressible and the property of fabric compressibility is related to fabric bulk, loftiness, softness, fullness, etc. Further, fabric compressional resilience is closely related with the hand touch/feeling. It is clearly an important aspect of fabric quality and performance.
FAST-1 – compression
The test method is very simple, with fabric thickness measured under compression forces of 2 gf/cm² and 100 gf/cm², viz.
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T2 Thickness (mm) at 2gf/cm² T100 Thickness (mm) at 100 gf/cm²
The thickness of a fabric under low pressure of 2 gf/cm² can be regarded as its basic thickness. The difference between these thickness values is called the surface thickness and is related to the fabric handle. The surface thickness is given by,
ST = T2 - T100
Table 15: FAST compression data Fabric T2 mm T100 mm ST mm
Mohair Tropical Suiting 0.339 0.272 0.067
Wool Tropical Suiting 0.337 0.278 0.059
Mohair Gongskin 0.607 0.509 0.098
Wool Gongskin 0.650 0.544 0.106
Table 15 presents the mean value results for the various FAST thickness parameters. As can be clearly seen, the wool and mohair fabrics are comparable within each category, but the Gongskin fabrics are approximately twice as thick as the tropical suiting fabrics. Further, the surface thickness of the Gongskin fabrics is greater than for the tropical suiting fabrics, indicating that these fabrics would be expected to be softer in handle.
KESF-FB3 compression
A constant rate of compressional deformation is applied to the sample until the upper limit of compressional force (50 gf/cm2) is reached, after which a recovery process is carried out. Both deformation and compressional forces were recorded with an X-Y recorder. From the recorded curve, following parameters were calculated, T0 (mm) fabric thickness at 0.5 gf/cm2 pressure TM (mm) fabric thickness at 50 gf/cm2 pressure EMC (%) (T0–TM)/T0 LC linearity of the compression-thickness curve WC (gf.cm/cm2) compression energy at 50 gf/cm2 RC (%) compressional resilience
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Table 16: KESF compression data Fabric T0 TM EMC LC WC RC
Mohair Tropical Suiting 0.392 0.270 31.09 0.039 0.118 75.63
Wool Tropical Suiting 0.499 0.278 44.19 0.023 0.128 76.35
Mohair Gongskin 0.712 0.508 28.65 0.032 0.162 60.07
Wool Gongskin 0.743 0.542 27.06 0.034 0.171 55.73
Table 16 presents the KESF compression test results for the four fabrics. Again, similar trends in thickness between the fabrics are observed as for the FAST results, with differences in magnitude being associated with the different applied load levels at which the thickness parameters are determined. Further, the results suggest that the wool tropical suiting fabric is highly nonlinear and more compressible and resilient (ie. with less hysteresis exhibited in the load cycle) than the other fabrics. In comparison, the mohair tropical suiting fabric had the highest linearity of all the fabrics with similar resilience to its wool counterpart. The gongskin fabrics were quite comparable in the compressional properties.
6.3.4 Bending Bending properties are important not only for aesthetic characteristics such as drape and handle, but also in the making-up of an acceptable garment. The FAST-2 Bending Meter is designed to measure the bending length of a 50 mm wide strip of fabric. The fabric bends under its own weight until its leading edge intercepts a plane at an angle of 41.5 degrees from the horizontal. The bending length C is recorded and the bending rigidity B is calculated as follows
B = W x C3 x 9.81 x 10-6 (µN.m) where W is the fabric mass per unit area (g/m²).
FAST-2 – bending
Tables 17 and 18 present the FAST bending test results for the tropical suiting fabrics and Gongskin fabrics, respectively. These results indicate differences in bending properties not only between the fabrics but also with respect to whether the bending deformation is applied
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about the warp or weft direction and the face or back fabric surface. Clearly, the tropical suiting fabrics have lower bending rigidities as compared to the Gongskin fabrics due to the smaller quantity of fibre being bent (cf. areal density values).
Table 17: FAST bending test data for tropical suiting fabrics MOHAIR WOOL TROPICAL SUITING Warp Weft Warp Weft FACE C 23.1 21.1 22.5 22.9 B 18.36 13.99 18.06 19.04 BACK C 22.8 22.2 23.5 21.6 B 17.65 16.30 20.57 15.98
Table 18: FAST bending test data for Gongskin fabrics MOHAIR WOOL GONGSKIN Warp Weft Warp Weft FACE C 24.0 19.4 23.7 18.2 B 37.62 19.87 37.98 17.20 BACK C 24.0 22.9 22.4 21.5 B 37.62 32.68 32.06 28.35
KES-FB2 bending
A specimen of fabric is bent to and recovered from a maximum curvature of +2.5 cm-1. The bending moment and corresponding fabric curvature are recorded simultaneously for one and a half full bending cycles. The fabric bending rigidity B and hysteresis of bending moment 2HB are then extracted from the graph. The unit of bending rigidity B is gf.cm2/cm. The unit of hysteresis of bending moment 2HB is gf.cm/cm.
Table 19 presents the KESF bending test data for the four fabrics. Again, differences in magnitude of bending rigidity between the tropical suiting fabrics and the gongskin fabrics is observed, with the latter being stiffer. Similarly, the gongskin fabrics show greater hysteresis that the tropical suiting fabrics. Further, within a fabric category the results indicate little difference in bending rigidity or hysteresis, with the exception of the wool tropical suiting fabric. The latter shows higher hysteresis when bending in the weft direction as compared to its mohair counterpart. This is attributed to the lower frictional properties of mohair fibre in the weft yarn. Consequently, the mohair tropical suiting fabric is the most resilient of the four fabrics in bending. That a similar observation cannot be made for the
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mohair gongskin fabric is attributed to the high warp sett increasing the internal frictional forces resisting fibre movement in bending recovery.
Table 19: KESF bending test data WARP WEFT FABRIC B 2HB B 2HB
Mohair Tropic Suiting 0.076 0.020 0.072 0.010
Wool Tropical Suiting 0.088 0.023 0.072 0.016
Mohair Gongskin 0.181 0.042 0.111 0.024
Wool Gongskin 0.175 0.042 0.101 0.026
Conversion of the bending rigidity data from the cgs system to SI units (viz. µN.m2/m) allows direct comparison of the KESF results with the FAST bending rigidity data if the face and back values of the latter are averaged. This comparison is presented in Table 20, where it can be seen that the FAST values are approximately 2.27 times the KESF bending rigidity values (range 2.04-2.48x). The FAST-2 Bending Meter is much cheaper and much easier to use, and therefore has greater potential for adoption by industry in general. However, the FAST instrument does not provide hysteresis data.
Table 20: Comparison of KESF and FAST bending rigidity data (SI units) B – KESF B – FAST FABRIC warp Weft warp Weft
Mohair Tropical Suiting 7.46 7.07 18.01 15.15
Wool Tropical Suiting 8.63 7.05 19.32 17.51
Mohair Gongskin 17.71 10.91 37.62 26.28
Wool Gongskin 17.19 9.94 35.02 22.78
6.3.5 Fabric tensile and shear properties Fabric tensile and shear properties play a key role in the tailoring of clothing and in all aspects of fabric performance during use. Fabrics are continually extended so that their recovery from extension or tensile resilience is of particular significance in practical use. Fabric shearing occurs whenever fabric is formed into a three-dimensional surface (such as
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in garment manufacture). This process of fabric shear can be related to extension of the fabric in its bias direction (ie. +45 degrees to the thread directions).
Measuring tensile and shear properties using the FAST-3 Extension Meter.
(1) Tensile properties
The FAST tensile test is a simple test requiring fabric extension to be measured for fixed applied loads (ie. weights). From this test the following tensile parameters are calculated: Formability, F Extension at 100 gf/cm, EB100, in % Extension at 20 gf/cm, EB20, in % Extension at 5 gf/cm, EB5, in % Bending Rigidity, B, in µN.m where F = (EB20-EB5) x B / 14.7
Table 21 presents the mean FAST tensile test data for the four fabrics, together with the calculated formability parameters. Clearly, the tropical suiting fabrics are anisotropic in tension, with the weft direction being more extensible than the warp direction. The gongskin fabrics, on the other hand, are approximately balanced. With respect to formability, higher values are observed for the mohair tropical suiting fabric as compared to its wool counterpart, indicating better tailorability in garment making-up. However, the opposite effect was recorded for the gongskin fabrics.
Table 21: FAST tensile test data Fabric EB 5 EB 20 EB 100 F Mohair Warp 0.34 0.74 1.90 0.49 Tropical Suiting Weft 0.52 1.70 4.88 1.22 Wool Warp 0.24 0.52 1.60 0.37 Tropical Suiting Weft 0.42 1.18 3.76 0.91 Mohair Warp 0.50 1.56 3.80 2.71 Gongskin Weft 0.50 1.48 4.16 1.75
Wool Warp 0.78 2.44 6.12 3.62 Gongskin Weft 0.8 2.54 6.98 2.70
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(2) Measurement of fabric shear (bias extension) properties
The FAST shear rigidity G (in N/m) is determined from the extension EB5 obtained from the tensile test conducted in the bias directions of the fabric, viz.
G = 123 / EB5
Table 22 presents the bias extension values together with shear rigidities for the four fabrics; the latter values are calculated from the average bias extensions. The results indicate that the tropical suiting fabrics are stiffer in shear than the gongskin fabrics. Whilst little difference is observed between the wool and mohair gongskin fabrics (due to the high warp sett), the mohair tropical suiting fabric has almost half of the shear rigidity of its wool counterpart. Coupled with the higher formability, this result suggests better tailorability performance for the mohair tropical suiting fabric as compared to the nominal wool equivalent.
Table 22: FAST bias extension and shear rigidity data
Fabric Bias Tensile Test EB5 G Left Right Average Mohair Tropical Suiting 3.52 3.62 3.57 34.45 Wool Tropical Suiting 1.86 2.12 1.99 61.81 Mohair Gongskin 4.62 4.14 4.38 28.08 Wool Gongskin 4.22 4.82 4.52 27.21
Measuring tensile and shear properties using KES-FB1 Tensile and Shear Tester
(1) Measuring fabric tensile properties
The mechanical properties of a fabric under tensile and shearing stresses is very important characteristics. In this instrument, a wide sample (20 cm) is clamped with a small span (5 cm) between clamps and then stretched. After reaching the maximum stress, 500 gf/cm, a recovery presses starts. Stress and deformation are all recorded through-out the cycle. This deformation is effectively a plan strain condition, ie. a form of biaxial deformation. For shear testing, the sample is given a constant tensile deformation and then a shear deformation is applied. From the recorded curve, the following parameters are extracted.
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LT linearity of load-extension curve - WT energy in extending the fabric to 500 gf/cm gf.cm/cm² RT tensile resilience % EMT fabric extension (extensibility) at 500 gf/cm %
Table 23 presents the means values of the KESF tensile parameters for the four fabrics. As can be seen, the results for extensibility follow similar trends to the FAST tensile data. When comparing the wool and mohair fabrics within each fabric category, only small differences are observes for the other parameters with the exception of weft tensile properties for the tropical suiting fabrics. The mohair version is more linear and requires greater energy for extension but is less resilient.
Table 23: KESF tensile data WARP WEFT Fabric LT WT RT EMT LT WT RT EMT Mohair Tropical 1.53 8.88 66.9 2.31 1.58 26.28 48.2 6.61 Suiting Wool Tropical 1.59 9.14 66.7 2.30 1.48 18.3 60.8 4.94 Suiting Mohair 1.29 16.2 58.3 5.04 1.46 21.1 56.5 5.77 Gongskin Wool 1.22 18.2 56.3 5.92 1.26 23.6 55.6 7.46 Gongskin
(2) Measurement of fabric shear properties using KES-FB 1 Tensile and Shear Tester
The parameters obtained from the KESF shear test are,
G shear rigidity (slop between 0.5º and 5º shear angle) gf / (cm.degree) 2HG hysteresis of shear force at 0.5 degrees gf / cm 2HG5 hysteresis of shear force at 5 degrees gf / cm
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Table 24 presents the KESF shear property data for the four fabrics. The shear rigidity values follow similar trends to the FAST shear rigidity vales. In terms of shear hysteresis, the gongskin fabrics have approximately similar values whereas the tropical suiting fabrics have higher hysteresis at low shear angles (2HG). Of particular note is 2HG5 value for the mohair tropical suiting fabric. This is the lowest hysteresis value of all the fabrics.
Table 24: KESF shear data WARP WEFT Fabric G 2HG 2HG5 G 2HG 2HG5 Mohair Tropical 0.605 0.38 0.27 0.566 0.36 0.21 Suiting Wool Tropical 0.985 0.40 0.69 0.968 0.33 0.65 Suiting Mohair 0.552 0.19 0.40 0.429 0.21 0.39 Gongskin Wool 0.548 0.18 0.53 0.486 0.17 0.45 Gongskin
6.3.6 Determination of fabric surface contour and friction
KES-FB4 Surface Tester
A fabric surface may be described as smooth, sleek, rough, prickly, etc. The KES-FB4 surface tester is the instrument for objective measurement of fabric surface properties. A contactor made of piano wire is placed, under constant pressure, against the face and then the back surface of a fabric specimen. The deviation of fabric thickness is recorded, from which the mean deviation of surface contour SMD is calculated. Surface friction is measured by using another contactor (made of ten pieces of the same wire as the contactor used for the roughness measurement) placed on the surface of specimen with the compression force of 50 gf. For both tests, the fabric is moved at constant velocity under the contactors. The KESF parameters derived from this instrument are,
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MIU Coefficient of friction - NMD Mean deviation of MIU - SMD Geometrical roughness µm
Table 25 presents the KESF surface property data. In general, the tropical suiting fabrics have greater surface roughness as compared to the gongskin fabrics. In addition, all fabrics showed higher roughness in their weft direction as compared to their warp direction. In terms of friction, the tropical suiting fabrics showed lower coefficients in the weft direction that the gongskin fabrics. However, all fabrics displayed higher variability in friction in the weft direction as compared to the warp direction. These effects appear to be structural rather than fibre type dependent.
Table 25: KESF surface property data WARP WEFT Fabric MIU MMD SMD MIU MMD SMD Mohair Tropical 0.1555 0.0167 4.42 0.1345 0.0238 6.576 Suiting Wool Tropical 0.1531 0.0239 5.529 0.1434 0.0302 7.067 Suiting Mohair 0.1640 0.0104 2.395 0.1935 0.0153 3.327 Gongskin
Wool 0.1150 0.0089 1.831 0.2023 0.0172 3.994 Gongskin
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7. CONCLUSION AND SUGGESTION FOR FURTHER WORK
Mohair fibre is a beautiful animal fibre. Its soft and smooth handle together with its ability to be dyed into bright colours make it very desirable for apparel applications. Consequently, mohair fibre has excellent potential for further development.
Mohair spinning is generally thought to be very difficult due to the lack of cohesion between mohair fibres. This research project has demonstrated solutions to critical processing problems. The sliver twister built for this research is an example.
Another problem related to the thickness of mohair fibre has also been addressed in this research. The composite yarn approach and the innovative “three-in-one” process not only make fine mohair yarn possible but also greatly reduce the twist levels of mohair yarn. The result is fine mohair yarns of low twist. The fabrics produced from such yarns are soft, light in weight and have excellent handle.
The fine and low-twist mohair yarn technology has created the possibility for further mohair product development. Although work has been undertaken in this area, it is clear that further efforts can be made in terms of making very fine pure mohair yarns and fabrics. The current research makes use of fine nylon filament or blends of mohair with wool. If the nylon filament is replaced by a water-soluble filament, very fine 100% mohair yarns may be produced. The coarseness of mohair is its biggest disadvantage for apparel applications. There is a need to reduce the fibre diameter of mohair through either breeding or fibre engineering. Reducing the diameter of mohair by fibre engineering (eg. stretching) is one option that needs to be exploited, as in the wool industry. Another option is to produce very fine yarns through yarn engineering. Without such work, mohair will be further disadvantaged because of its relative coarseness. While the industry correctly places emphasis on product developments, it is often not well understood that developing new products means developing new yarns and new fibres. This is the approach taken by the synthetic fibre industry, with its fundamental research in the developments of microfibres and Shingosen fabrics [Okamoto and Kajiwara 1997]. Basic and applied research in the engineering of mohair fibres, yarns and fabrics is needed to drive the innovative process of product development.
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REFERENCES
1. Aldrich D V, Kruger P J, and Turpie D W F (1970), The Carding and Combing of Wools of Different Fibre Lengths, SAWTRI Techn. Report, No 136. 2. Barella A (1956), Bull. Inst. Test. France, No. 61, 55. 3. Buxton A (1986), Text. Outlook Int., No 11, 67. 4. Cilliers WC (1968), SAWTRI Technical Report, No 111. 5. Cilliers WC (1969), Spinning Mohair using the Bradford System as well as a Combined Bradford/French System, SAWTRI Technical Report , No123. 6. Frishman, D., Smith, A.L, and Harris, M. (1948), Textile Res. J., Vol. 18, 475. 7. Hearle J W S, and Aly El-Sheikh (1965), The Mechanics of Wool Yarns, 3rd International Wool Textile Conference, p267, Section 4, Paris. 8. Hunter, L (1993), Mohair: A review of its properties, processing and applications, International Mohair Association. 9. Jou G T, East G C, Lawrence C A, and Oxenham W J (1996), J. Textile Inst., 87, Part 1 (1) 78-96. 10. Kenins P (1992), The cause of Prickle and the Effect of Some Fabric Construction Parameters on Prickle Sensations, Wool Tech. Sheep Breed., p19-24, March/April 1992. 11. Knott, J. (1990), Fine Animal Fibres and Their Depigmentation Process, Eurotex. 12. Leeder, J.D., McGregor, B.A. and Steadman, R.G. (1992), A review and interpretation of existing research results on raw-fibre-to-end-product properties and performance of goat fibres, RIRDC. 13. ISTM D2612-93A, Standard Test Method for Fibre Cohesion in Sliver and Top in Static Tests. 14. Kalyanarman A R (1992), A Process to Control Hairiness in Yarn, J. Textile Inst., 83, No 3, 407-413. 15. Martindale JG (1945), A New Method of Measuring the Irregularity of Yarns with Some Observations on the Origin of Irregularities in Worsted Slivers and Yarns, J. Textile Inst., 36, T35-T47.
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16. Naylor GRS (1992), The Role of Coarse Fibres in Fabric Prickle Using Blended Acrylic Fibres of Different Diameters, Wool. Tech. Sheep Breed., p14-18, March/April 1992. 17. Okamoto M and Kajiwara K (1997), Shingosen: Past, Present, and Future, Textile progress, 27, No 2. 18. Oxtonby E (1987), Spun Yarn Technology, Butterworth & Co. Ltd. 19. Patharasarathy M S (1966), Proc. 8th Technol. Conf. ATIRA, BTRA, SITRA, 68. 20. Pillay, K R P (1964), Textile Res. J., 34, 663-783. 21. Robinson ATC and Marks R (1973), Woven Cloth Construction, The Textile Institute. 22. Sawhney APS, Robert KQ , Ruppencicker GF, and Kimmel LB (1992), Improved Method of Producing A Cotton Covered/Polyester Staple-core Yarn on A Ring Spinning Frame, Textile Res. J, 62, 21-25. 23. Sawhney APS, Robert KQ, and Ruppenicker G F (1989), Device or Producing Staple-core/Cotton-wrap Ring Spun Yarn, Textile Res. J., 59, 519 – 524 24. Selling H J (1971), Twistless Yarn, Merrow Publishing Co. Ltd. 25. Slinger R I, and Robinson G A (1968), SAWTRI Technical Report , No 160. 26. Smith P A, and Oxenham W (1991), Yarn-Production Machinery, Textile Horizons, No 11, 20-25. 27. Tang N K H, Pickering J F, and Freeman J M (1993), An Investigation into the Control of Brushed Yarn Properties: The Application of Machine and Experimental Work, J. Textile Inst., 84, No. 2, 156-165. 28. Turpie, D.W.F. [1985], SAWTRI Special Publication - June 1985. 29. Turpie, D.W.F. and Godawa, T.O. (1994), SAWTRI Techn. Rep. No 213. 30. Turpie, D W F,Kruger P J, and Hunter L (1972), A Study of the Lubrication of Mohair Part II: Lubrication in Processing, SAWTRI Technical Report, No 160. 31. Veitch CJ and Naylor GRS (1992), The Mechanics of Fibre Buckling in Relation to Fabric-evoked Prickle, Wool Tech. Sheep Breeding, March/April 1992. 32. Veldsman D P (1970), From Mohair Fleece to Fabric – An Account of SAWTRI’s Research, SAWTRI Special Publication. 33. Valdsman D P (1980), Latest Trends in Processing Mohair, International Wool Textile Conference, I, 195, Pretoria.
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34. Wang X, Miao M and How Y (1997), Studies of JetRing spinning - part 1: Reducing yarn hairiness with the JetRing, Textile Res. J, 67(4), 253-258 (1997) 35. Wang X and Miao M (1997), Reducing Yarn Hairiness with an Air Jet Attachment during Winding, Textile Res. J., 67(7), 481-485. 36. Wang X (1997), Effect of Testing Speed on the Hairiness of Ringspun and Sirospun Yarns, J. Textile Inst. 88 Part 1, No 2, 99-106 (1997) 37. Wang X (1998), Measuring the Hairiness of a Rotor Spun Yarn on the Uster Tester 3 at Different Speeds, J. Textile Inst., 89 Part 1, No 2, 281-288 (1988).
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APPENDIX 1: Mohair knitting yarns I
The following lists the mohair knitting yarns used to produce the weft-knitted fabric samples that accompanied the project milestone report in 1997.
1. Soft yarn of fine hair fibres Yarn count 50 tex including 15 denier nylon filament Yarn twist 368 t/m Z De-twist 235 t/m S ‘three in one’ processed Ply twist 235 t/m S
2. Soft yarn of hair fibres Yarn count 50 tex including 15-denier nylon filament Yarn twist 368 t/m Z De-twist 210 t/m S Ply twist 110 t/m S
3. Coarse yarn of fine hair fibres Yarn count 70 tex including 15-denier nylon filament Yarn twist 280 t/m Z De-twist 235 t/m S ‘three in one’ processed Ply twist 235 t/m S
4. Normal yarn of hair fibres Yarn count 50 tex Yarn twist 368 t/m Z Ply twist 220 t/m S
5. Fine yarn of fine hair fibres Yarn count 20 tex including 15-denier nylon filament Yarn twist 567 t/m Z De-twist 235 t/m S ‘three in one’ processed Ply twist 235 t/m S
6. Fine yarn of hair fibres Yarn count 30 tex including 15-denier nylon filament Yarn twist 442 t/m Z De-twist 180 t/m S ‘three in one’ processed Ply twist 180 t/m S
7. Fine yarn of hair fibres Yarn count 40 tex Yarn twist 442 t/m Z single yarn
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8. Fine yarn of hair fibres Yarn count 40 tex Yarn twist 440 t/m single yarn
9. soft yarn of 85 % fine kid fibres blended with 15 % wool Yarn count 50 tex including 15-denier nylon filament Yarn twist 368 t/m Z De-twist 110 t/m S ‘three in one’ processed Ply twist 110 t/m S
10. Zero twist yarn of 85 % fine kid mohair blended with 15 % wool Yarn count 50 tex including 15-denier nylon filament Yarn twist 368 t/m Z De-twist 368 t/m S Ply twist 110 t/m S
11. Soft yarn of 85 % fine kid mohair blended with 15 % wool Yarn count 30 tex including 15-denier nylon filament Yarn twist 380 t/m Z De-twist 152 t/m S ‘three in one’ processed Ply twist 152 t/m S
12. fine yarn of 85 % fine kid mohair blended with 15 % wool Yarn count 25 tex including 15-denier nylon filament Yarn twist 442 t/m Z De-twist 235 t/m S ‘three in one’ processed Ply twist 235 t/m S
13. Fine yarn of 85 % fine kid mohair blended with 15 % wool Yarn count 20 tex including 15-denier nylon filament Yarn twist 440 t/m Z Ply twist 293 t/m S
14. Fine yarn of 85 % fine kid mohair blended with 15 % wool Yarn count 20 tex including 15-denier nylon filament Yarn twist 544 t/m Z De-twist 235 t/m S ‘three in one’ processed Ply twist 235 t/m S
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APPENDIX 2: Mohair knitting yarns II
The following lists the mohair knitting yarns used to produce the weft-knitted fabric samples that accompany this report.
1) 80 tex mohair yarn containing 15 % wool Yarn count 80 tex X 2 Single yarn twist 291 t/m Ply twist 194 t/m
2) 60 tex mohair yarn containing 15 % wool Yarn count 60 tex X 2 Single yarn twist 335 t/m Ply twist 223 t/m
3) 50 tex mohair yarn containing 15 % wool Yarn count 50 tex X 2 Single yarn twist 377 t/m Ply twist 254 t/m
4) 40 tex mohair yarn containing 15 % wool Yarn count 40 tex X 2 Single yarn twist 427 t/m Ply twist 285 t/m
5) 30 tex mohair yarn containing 15 % wool Yarn count 30 tex X 2 Single yarn twist 475 t/m Ply twist 317 t/m
6) 20 tex mohair yarn containing 15 % wool and 15-denier nylon filament Yarn count 20 tex X 2 Single yarn twist 564 t/m Ply twist 381 t/m
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APPENDIX 3: Test results for worsted mohair and wool fabrics
The following tables list the specimen results for the various physical and mechanical property tests described in section 5.3.
Mohair Tropical Suiting Mass per area Sample No Mass ( g ) Area (M2) Mass per area ( g / M2 ) 1 6.102 0.04 152.55 2 6.044 0.04 151.10 3 6.092 0.04 152.30 4 6.069 0.04 151.73 5 6.057 0.04 151.43 Average 151.82
Wool Tropical Suiting Mass per area Sample No Mass ( g ) Area (M2) Mass per area ( g / M2 ) 1 6.504 0.04 162.60 2 6.464 0.04 161.60 3 6.428 0.04 160.70 4 6.433 0.04 160.83 5 6.490 0.04 162.25 Average 161.60
Mohair Gongskin Mass per area Sample No Mass ( g ) Area (M2) Mass per area ( g / M2 ) 1 11.118 0.04 277.95 2 10.920 0.04 273.00 3 11.082 0.04 277.05 4 11.103 0.04 277.58 5 11.253 0.04 281.33 Average 277.38
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Wool Gongskin Mass per area Sample No Mass ( g ) Area (M2) Mass per area ( g / M2 ) 1 11.671 0.04 291.98 2 11.626 0.04 290.65 3 11.718 0.04 292.95 4 11.544 0.04 288.60 5 11.595 0.04 289.88 Average 290.81
Tropical Suiting Compression test - FAST Mohair Wool Sample No T2 mm T100 mm T2 mm T100 mm 1 0.360 0.283 0.336 0.280 2 0.367 0.283 0.345 0.284 3 0.337 0.275 0.330 0.275 4 0.342 0.274 0.339 0.281 5 0.336 0.268 0.331 0.278 6 0.333 0.269 0.334 0.277 7 0.326 0.266 0.333 0.276 8 0.331 0.272 0.332 0.276 9 0.324 0.266 0.337 0.278 10 0.332 0.267 0.350 0.278 Average 0.339 0.272 0.337 0.278 ST 0.067 0.059
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Gongskins Compression test - FAST Mohair Wool Sample No T2 T100 T2 T100 1 0.611 0.515 0.658 0.540 2 0.618 0.518 0.637 0.537 3 0.599 0.506 0.670 0.559 4 0.611 0.505 0.653 0.546 5 0.611 0.517 0.649 0.544 6 0.601 0.506 0.646 0.540 7 0.604 0.504 0.658 0.551 8 0.601 0.503 0.642 0.541 9 0.600 0.505 0.645 0.540 10 0.611 0.512 0.640 0.542 Average 0.607 0.509 0.650 0.544 ST 0.098 0.106
Tropical suiting Compression Test - KESF MOHAIR T0 TM EMC LC WC RC 1 0.375 0.275 26.67 0.0392 0.098 77.55 2 0.390 0.270 30.77 0.0377 0.113 74.34 3 0.385 0.270 29.87 0.0355 0.102 72.55 4 0.380 0.265 30.26 0.0348 0.100 77.00 5 0.400 0.277 30.75 0.0384 0.118 75.42 6 0.370 0.255 31.08 0.0584 0.168 85.12 7 0.385 0.272 29.35 0.0400 0.113 76.11 8 0.375 0.265 29.33 0.0389 0.107 73.83 9 0.425 0.275 35.29 0.0339 0.127 66.93 10 0.440 0.275 37.50 0.0322 0.133 77.44 Average 0.392 0.270 31.09 0.0389 0.118 75.63
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Tropical suiting Compression Test - KESF WOOL T0 TM EMC LC WC RC 1 0.500 0.282 43.60 0.0198 0.108 75.93 2 0.515 0.275 46.60 0.0282 0.169 78.70 3 0.475 0.270 43.16 0.0338 0.173 79.19 4 0.505 0.285 43.56 0.0198 0.109 77.06 5 n.a n.a n. a. n.a n.a n.a 6 0.480 0.276 42.50 0.0202 0.103 81.55 7 0.485 0.278 42.68 0.0205 0.106 75.47 8 0.460 0.277 39.78 0.0210 0.096 70.83 9 0.525 0.282 46.29 0.0179 0.109 66.97 10 0.545 0.275 49.54 0.0264 0.178 81.46 Average 0.499 0.278 44.19 0.0231 0.128 76.35
Gongskin Compression Test - KESF Mohair T0 TM EMC LC WC RC 1 0.710 0.500 29.58 0.0297 0.156 61.54 2 0.690 0.500 27.54 0.0324 0.154 62.34 3 0.740 0.515 30.41 0.0290 0.163 61.35 4 0.720 0.515 28.47 0.0312 0.160 60.00 5 0.695 0.505 27.34 0.0352 0.167 59.88 6 0.725 0.505 30.34 0.0322 0.177 61.02 7 0.725 0.510 29.66 0.0309 0.166 59.64 8 0.720 0.510 29.17 0.0316 0.166 59.04 9 0.700 0.515 26.43 0.0337 0.156 58.33 10 0.690 0.500 27.54 0.0322 0.153 57.52 Average 0.712 0.508 28.65 0.0318 0.162 60.07
Gongskin Compression Test - KESF Wool T0 TM EMC LC WC RC 1 0.750 0.545 27.33 0.0365 0.187 54.01 2 0.735 0.540 26.53 0.0334 0.163 53.99 3 0.730 0.540 26.03 0.0328 0.156 55.13 4 0.760 0.550 27.63 0.0330 0.173 53.18 5 0.730 0.535 26.71 0.0326 0.159 55.35 6 0.740 0.540 27.03 0.0322 0.161 55.28 7 0.750 0.535 28.67 0.0313 0.168 58.93 8 0.750 0.545 27.33 0.0367 0.188 54.79 9 0.730 0.535 26.71 0.0370 0.180 61.11 10 0.750 0.550 26.67 0.0346 0.173 55.49 Average 0.743 0.542 27.06 0.0340 0.171 55.73
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Tropical Suiting Bending Test - FAST Mohair Wool Warp Weft Warp Weft C (mm) C (mm) C (mm) C (mm) 1 Face 23.0 20.5 22.0 22.5 2 Face 23.0 21.0 23.0 23.0 3 Face 23.5 21.0 23.0 23.0 4 Face 23.0 21.0 22.5 23.0 5 Face 23.0 22.0 22.0 23.0 Average C 23.1 21.1 22.5 22.9 B 18.36 13.99 18.06 19.04 1 Back 23.5 21.5 22.5 21.5 2 Back 22.5 21.5 23.5 22.0 3 Back 23.0 22.5 23.0 22.0 4 Back 22.0 22.5 24.0 21.5 5 Back 23.0 23.0 24.5 21.0 Average C 22.8 22.2 23.5 21.6 B 17.65 16.30 20.57 15.98
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Gongskin Bending Test - FAST Mohair Wool Warp Weft Warp Weft C (mm) C (mm) C (mm) C (mm) 1 Face 24.0 19.5 23.5 16.0 2 Face 24.5 19.5 23.5 18.0 3 Face 23.0 19.0 23.5 20.0 4 Face 24.5 19.5 24.0 19.5 5 Face 24.0 19.5 24.0 17.5 Average C 24.0 19.4 23.7 18.2 B 37.62 19.87 37.98 17.20 1 Back 24.0 23.0 23.0 21.0 2 Back 24.0 23.5 22.5 21.0 3 Back 24.0 22.5 22.5 20.5 4 Back 24.0 22.5 21.5 23.0 5 Back 24.0 23.0 22.5 22.0 Average C 24.0 22.9 22.4 21.5 B 37.62 32.68 32.06 28.35
Mohair Tropical suiting Bending Test - KESF Warp Weft B 2HB B 2HB 1 0.0813 0.0163 0.0755 0.0150 2 0.0788 0.0225 0.0645 0.0100 3 0.0720 0.0175 0.0700 0.0093 4 0.0763 0.0213 0.0763 0.0068 5 0.0718 0.0210 0.0738 0.0113 Average 0.07604 0.01971 0.07202 0.01045
Wool Tropical suiting Bending Test - KESF Warp Weft B 2HB B 2HB 1 0.0905 0.0213 0.0750 0.0200 2 0.0838 0.0153 0.0688 0.0130 3 0.0825 0.0275 0.0675 0.0138 4 0.0908 0.0288 0.0725 0.0163 5 0.0925 0.0200 0.0758 0.0148 Average 0.0880 0.0226 0.0719 0.0156
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Mohair Gongskin Bending Test - KESF Warp Weft B 2HB B 2HB 1 0.1725 0.0438 0.1100 0.0238 2 0.1813 0.0363 0.1275 0.0245 3 0.1813 0.0375 0.1050 0.0245 4 0.1775 0.0500 0.1058 0.0188 5 0.1900 0.0438 0.1075 0.0275 Average 0.1805 0.0423 0.1112 0.0238
Wool Gongskin Bending Test - KESF Warp Weft B 2HB B 2HB 1 0.1775 0.0438 0.1000 0.0238 2 0.1713 0.0400 0.0975 0.0245 3 0.1720 0.0425 0.1000 0.0250 4 0.1775 0.0413 0.1050 0.0245 5 0.1775 0.0418 0.1038 0.0298 Average 0.1752 0.0419 0.1013 0.0255
Mohair tropical suiting Tensile Test - FAST Warp Weft Sample No EB5 EB20 EB100 EB5 EB20 EB100 1 0.30 0.70 1.80 0.50 1.50 4.40 2 0.30 0.70 1.80 0.50 1.80 5.00 3 0.40 0.80 1.90 0.50 1.60 4.80 4 0.40 0.80 2.10 0.60 1.80 5.20 5 0.30 0.70 1.90 0.50 1.80 5.00 Average 0.34 0.74 1.9 0.52 1.7 4.88
Wool Tropical Suiting Tensile Test - FAST Warp Weft Sample No EB5 EB20 EB100 EB5 EB20 EB100 1 0.30 0.60 1.60 0.40 1.20 3.90 2 0.20 0.50 1.60 0.40 1.20 3.70 3 0.20 0.50 1.60 0.50 1.20 3.80 4 0.30 0.50 1.60 0.40 1.10 3.60 5 0.20 0.50 1.60 0.40 1.20 3.80 Average 0.24 0.52 1.6 0.42 1.18 3.76
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Mohair Gongskin Tensile Test - FAST Warp Weft Sample No EB5 EB20 EB100 EB5 EB20 EB100 1 0.50 1.60 3.80 0.50 1.50 4.30 2 0.50 1.50 3.70 0.50 1.40 4.00 3 0.50 1.50 3.70 0.50 1.50 4.10 4 0.50 1.60 3.90 0.50 1.50 4.10 5 0.50 1.60 3.90 0.50 1.50 4.30 Average 0.50 1.56 3.80 0.50 1.48 4.16
Wool Gongskin Tensile Test - FAST Warp Weft Sample No EB5 EB20 EB100 EB5 EB20 EB100 1 0.80 2.40 6.00 0.80 2.60 7.20 2 0.70 2.40 6.10 0.80 2.50 6.90 3 0.80 2.40 6.10 0.80 2.50 6.80 4 0.80 2.50 6.30 0.80 2.60 7.20 5 0.80 2.50 6.10 0.80 2.50 6.80 Average 0.78 2.44 6.12 0.8 2.54 6.98
Tropical Suitings Shear Test - FAST Mohair Wool Bias Tensile Test EB5 Bias Tensile Test EB5 Sample No Left Right Left Right 1 3.5 3.6 1.9 2.2 2 3.3 3.4 1.8 2.1 3 3.7 3.9 1.8 2.2 4 3.4 3.6 2.1 1.9 5 3.7 3.6 1.7 2.2 Average 3.52 3.62 1.86 2.12
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Gongskin Shear Test - FAST Mohair Wool Bias Tensile Test EB5 Bias Tensile Test EB5 Sample No Left Right Left Right 1 4.6 4.2 4.2 5.3 2 4.3 4.1 4.7 4.7 3 5.0 3.9 4.0 4.4 4 4.7 4.3 4.2 4.8 5 4.5 4.2 4.0 4.9 Average 4.62 4.14 4.22 4.82
Mohair tropical suiting Tensile Test - KESF WARP WEFT LT WT RT EMT LT WT RT EMT 1 1.4579 7.80 69.87 2.14 1.4900 22.35 53.91 6.00 2 n.a. n.a. n.a. n.a. 1.6556 29.80 43.96 7.20 3 1.6000 9.80 62.76 2.45 1.5783 25.45 49.12 6.45 4 1.5217 8.75 73.14 2.30 1.4309 22.00 55.91 6.15 5 1.5508 9.15 61.75 2.36 1.7545 31.80 38.21 7.25 Mean 1.5326 8.88 66.88 2.31 1.5819 26.28 48.22 6.61
Wool tropical suiting Tensile Test - KESF WARP WEFT LT WT RT EMT LT WT RT EMT 1 1.5130 8.70 68.97 2.30 1.4139 17.85 63.31 5.05 2 1.6638 9.65 62.69 2.32 1.4969 18.15 60.06 4.85 3 1.5771 8.95 69.27 2.27 1.5216 18.45 57.45 4.85 4 n.a. n.a. n.a. n.a. 1.4849 18.45 61.25 4.97 5 1.6087 9.25 65.95 2.30 1.4720 18.40 61.68 5.00 Mean 1.5907 9.14 66.72 2.30 1.48 18.26 60.75 4.94
Mohair Gongskin Tensile Test - KESF WARP WEFT LT WT RT EMT LT WT RT EMT 1 1.2559 14.60 62.67 4.65 1.4379 20.85 57.55 5.80 2 1.2648 16.60 66.27 5.25 1.5098 23.10 52.38 6.12 3 1.2495 16.15 54.18 5.17 1.4526 20.70 57.73 5.70 4 1.3258 17.50 51.14 5.28 1.4638 20.75 56.63 5.67 5 1.3443 16.30 57.06 4.85 1.4399 20.05 58.10 5.57 Mean 1.2881 16.23 58.26 5.04 1.4608 21.09 56.48 5.77
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Wool Gongskin Tensile Test - KESF WARP WEFT LT WT RT EMT LT WT RT EMT 1 1.3375 21.40 48.83 6.40 1.3455 27.75 49.01 8.25 2 1.3248 20.70 49.28 6.25 1.3753 27.85 48.83 8.10 3 1.2315 18.35 55.04 5.96 1.2703 23.50 54.04 7.40 4 1.0982 15.10 65.23 5.50 1.1647 19.80 60.10 6.80 5 1.1236 15.45 63.11 5.50 1.1289 19.05 65.88 6.75 Mean 1.2231 18.20 56.30 5.92 1.2569 23.59 55.57 7.46
Mohair Tropical Suiting Shear Test - KESF WARP WEFT G 2HG 2HG5 G 2HG 2HG5 1 0.5733 0.24 0.40 0.5889 0.32 0.22 2 0.6044 0.43 0.26 0.56 0.32 0.27 3 0.6489 0.41 0.20 0.5556 0.30 0.22 4 0.6133 0.37 0.33 0.5889 0.52 0.12 5 0.5867 0.47 0.15 0.5378 0.33 0.20 Mean 0.6053 0.38 0.27 0.5662 0.36 0.21
Wool Tropical Suiting Shear Test - KESF WARP WEFT G 2HG 2HG5 G 2HG 2HG5 1 1.0111 0.40 0.88 0.9667 0.34 0.62 2 0.9556 0.50 0.60 0.9556 0.40 0.63 3 1.0222 0.50 0.70 0.9956 0.52 0.65 4 0.9556 0.28 0.58 0.9444 0.35 0.60 5 0.9778 0.30 0.70 0.9778 0.035 0.73 Mean 0.9845 0.40 0.69 0.9680 0.33 0.65
Mohair Gongskin Shear Test - KESF WARP WEFT G 2HG 2HG5 G 2HG 2HG5 1 0.5400 0.23 0.36 0.5556 0.18 0.47 2 0.5067 0.12 0.48 0.2667 0.15 0.36 3 0.5289 0.15 0.42 0.2333 0.20 0.40 4 0.6022 0.23 0.28 0.5111 0.25 0.38 5 0.5800 0.20 0.46 0.5778 0.27 0.36 Mean 0.5516 0.19 0.40 0.4289 0.21 0.39
69 Final Report Processing Performance and Fabric Properties of Australian Mohair
Wool Gongskin Shear Test - KESF WARP WEFT G 2HG 2HG5 G 2HG 2HG5 1 0.5644 0.20 0.64 0.4889 0.05 0.47 2 0.5844 0.20 0.52 0.5289 0.10 0.45 3 0.5600 0.23 0.55 0.4556 0.23 0.48 4 0.5222 0.18 0.44 0.4889 0.38 0.49 5 0.5111 0.10 0.52 0.4667 0.11 0.37 Mean 0.5484 0.18 0.53 0.4858 0.17 0.45
Wool Gongskin Surface Test - KESF WARP WEFT No MIU MMD SMD MIU MMD SMD 1 0.0529 0.0085 1.835 0.1970 0.0154 4.350 2 0.0534 0.0080 2.065 0.2115 0.0209 4.480 3 0.1550 0.0110 1.840 0.1980 0.0162 3.495 4 0.1525 0.0090 1.660 0.2045 0.0200 4.005 5 0.1615 0.0083 1.756 0.2005 0.0133 3.640 average 0.1150 0.0089 1.831 0.2023 0.0172 3.994
Mohair Gongskin Surface Test - KESF WARP WEFT MIU MMD SMD MIU MMD SMD 1 0.170 0.0122 2.615 0.2025 0.0134 3.130 2 0.165 0.0095 2.155 0.1930 0.0163 3.535 3 0.164 0.0094 2.275 0.1920 0.0159 3.445 4 0.161 0.0113 2.600 0.1870 0.0145 3.725 5 0.159 0.0097 2.330 0.1930 0.0160 2.800 average 0.164 0.0104 2.395 0.1935 0.0153 3.327
70 Final Report Processing Performance and Fabric Properties of Australian Mohair
Wool Tropical Suiting Surface Test - KESF WARP WEFT MIU MMD SMD MIU MMD SMD 1 0.1575 0.0251 4.505 0.1510 0.0265 7.025 2 0.1530 0.0230 6.445 0.1435 0.0366 7.210 3 0.1520 0.0242 5.305 0.1425 0.0306 7.135 4 0.1480 0.0255 5.870 0.1385 0.0293 7.060 5 0.1550 0.0220 5.520 0.1415 0.0279 6.885 average 0.1531 0.0239 5.529 0.1434 0.0302 7.063
Mohair Tropical Suiting Surface Test - KESF WARP WEFT no MIU MMD SMD MIU MMD SMD 1 0.1570 0.0156 4.22 0.1365 0.0252 7.045 2 0.1505 0.0175 4.63 0.1335 0.0253 6.230 3 0.1555 0.0165 4.30 0.1320 0.0242 6.540 4 0.1540 0.0176 4.46 0.1370 0.0196 6.425 5 0.1605 0.0162 4.49 0.1335 0.0249 6.640 average 0.1555 0.0167 4.42 0.1345 0.0238 6.576
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