Contents
Contributor contact details ix
Woodhead Publishing Series in Textiles xi
Part I Textile applications 1
1 The colouration of wool 3
D. M. LEWIS , The University of Leeds , UK
1.1 Introduction 3
1.2 Overview of industry practice 5
1.3 The theoretical basis of wool dyeing 6
1.4 Environmental impact of wool colouration processes 15
1.5 Reactive dyes for wool 22
1.6 Wool protection during dyeing by using reactive dyes and/or anti-setting agents 24
1.7 Ink-jet printing of wool fabrics 32
1.8 References 35
2 Dyeing of synthetic fibres 40
A. K. ROY CHOUDHURY , Government College of Engineering and Textile Technology , Serampore, India
2.1 Introduction 40
2.2 Mass colouration 41
2.3 Disperse dyes 47
2.4 Disperse dyes on acetate fibres 63
2.5 Disperse dyes on polyester fibres 63
2.6 Disperse dyes on texturised polyester 74
2.7 Disperse dyes on modified polyester 75
2.8 Disperse dyes on nylon 81
2.9 Disperse dyes on other fibres 82
2.10 Dyeing of nylon fibres 82
2.11 Anionic dyes on nylon 86
2.12 Reactive dyes on nylon 97
2.13 Dyeing of modified nylons 99
2.14 Dyeing of aramid fibres 101
2.15 Basic or cationic dyes 102
2.16 Dyeing of acrylic fibres with basic dyes 106
2.17 Dyeing of olefin fibres 121
2.18 Dyeing of elastomeric fibres 124
2.19 Future trends 125
2.20 References 125
3 Dyeing of cellulosic fibres 129
J . KOH , Konkuk University , South Korea
3.1 Introduction 129
3.2 Cellulosic fibres 129
3.3 Main methods of dyeing cellulosic fibres 133
3.4 Future trends 145
3.5 References 146
4 Dyeing of textile fibre blends 147
N. A. IBRAHIM , National Research Centre , Egypt
4.1 Introduction 147
4.2 Key fi bre blends 148
4.3 Dyeing of textile blends 151
4.4 Main dyeing methods 156
4.5 Future trends 159
4.6 Sources of further information and advice 168
4.7 Acknowledgement 169
4.8 References 169
Part II Industrial applications 173
5 Colourants and dyes for the cosmetics industry 175
R. J. W . HEFFORD , Independent Cosmetic Advice Ltd , UK
5.1 Introduction 175
5.2 Regulations and definitions 176
5.3 Raw material types and chemistry 181
5.4 Product types 196
5.5 Future trends 201
5.6 References 203
6 Dyes for the medical industry 204
M. WAINWRIGHT , Liverpool John Moores University , UK
6.1 Introduction 204
6.2 Dyes for indication 206
6.3 Dyes as colourants in medicines 208
6.4 Dyes for therapy 210
6.5 Medical photosensitisers 216
6.6 Potential adverse effects of dyes 222
6.7 Future prospects 226
6.8 References 227
7 Automotive dyes and pigments 231
B . KAUR AND S. N. BHATTACHARYA , RMIT University , Australia
7.1 Introduction 231
7.2 Key issues of automotive dyes and pigments 232
7.3 Major pigment types used in automotive coatings 235
7.4 Techniques commonly used to improve the technical performance of pigments 245
7.5 Application technology 246
7.6 Future trends in automotive pigments 248
7.7 References 250
8 Food colourants 252
A . P . DAMANT , Food Standards Agency , UK
8.1 Introduction 252
8.2 UK and EU legislation 254
8.3 Synthetic food colours 259
8.4 Illegal dyes 276
8.5 Natural dyes 278
8.6 Conclusions 296
8.7 Acknowledgements 297
8.8 References 297
Index 307
The colouration of wool
D. M. LEWIS, The University of Leeds, UK
Abstract : Perceived and real environmental threats have greatly influenced wool dyeing trends and much of these effects are detailed. In particular chrome dyeing has been under scrutiny and methods to avoid the use of extremely toxic Cr (VI) compounds are discussed. Damage in wool dyeing is an important theme and the use of anti-setting agents in wool dyebaths is fully described along with their modus operandi. In the latter case reactive dyes have much to offer especially in the case of those reacting by a Michael addition mechanism. Shrink-resist treatments to give machine-washable wool are discussed in terms of required dye selection and also the environmental hazards of Absorbable Organo Halogen (AOX) production if pre-chlorination is used. Recent developments in ink-jet printing and how they should favour wool fabric printing are described.
Key words : wool chemistry, acid dyes, chrome dyes, reactive dyes, dyeing theory, dyeing machine-washable wool, damage and wool setting, ink-jet printing.
1.1 Introduction
Animal fibres such as wool, cashmere and alpaca are highly prized when made into garments since these exhibit desirable properties such as soft touch, warmth, beautiful drape, excellent comfort in wear and, using modern synthetic dyes, unparalleled colouration possibilities with very few shade restrictions. Leeder 1 points out that wool has been bio-engineered over millions of years to be worn next to an animal’s skin, and is thus better than other types of fibres in terms of comfort in wear; it possesses the properties of absorbing up to 30% of its own weight of water without feeling wet, and even giving out heat when it absorbs water. Despite the above strong positives it has to be noted that wool makes up less than 5% of the textile market, cotton and synthetic fibres making up the bulk – it would not be possible for wool growing to increase significantly and therefore wool must position itself mainly in the desirable ‘luxury’ item sector of the market. There are also performance disadvantages, which are not present in garments made from the other textile fibres; these include felting shrinkage (in knitwear this can be as high as 60%) during household laundering procedures, the need to scour the raw wool to remove lanolin, soil and seeds, and attack by moths and beetles during garment storage.