Wool dyeing

It is used in the dispersed form as a dye for acetate silk, though it has no affinity for other fibres. It is also used as a starting point for alkyl- or acyl-aminoanlhraquinones which are used either as vat dyes or, after sulphona-tion, as acid wool dyes. 

Wool-acrylic blends Wool combing Wool-cotton blends Wool dyes Woolen systems... 

C. L. Bind, The Theoy and Practice of Wool Dyeing Society of Dyers and Coloudsts, Bradford, U.K., 1972. 

Other modifications of acid wool dyes have groups which react by nucleophilic substitution of basic groups ia proteia fibers (NH2 groups, etc). The iatroduction of Procion dyes by ICI ia 1956 was the most important development ia the field of technological azo dye chemistry. Chemically, many of the reactive dyes are prepared from the group of the anionic monoazo dyes (see Dyes, reactive). 

Premetallized Dyes. Although discovered in 1912, the 1 1 chromium complexes known as Palatine Fast (BASF) and Neolan (Ciba) dyes had httie practical use as wool dyes until 1920 when it was found that a strongly acidic dyebath (pH ca 2.0) (51) was requited to obtain satisfactory dyeing and acceptable fastness properties. Dyes of this type exemplified by Neolan Blue 2G [6370-12-3] (57) (Cl Acid Blue 158A Cl 15050) are stiU in use despite the damage to the wool caused by the strong acid in the dyebath. 

Among anthraquiaoae dyes (see Dyes, anthraquinone). Acid Blue 78 [6424-75-5] C2 H25BrN20 S -Na, or Alizarin Pure Blue B, is a wool dye. Bromamine acid [116-81-4] (l-amiao-4-bromoanthraquiaoae-2-sulfonic acid), C24HgBrNO S, is a useful dye iatermediate. A number of bromo anthraquiaoae, pyrathroae, and benzanthrone dyes are known. 

Localised unlevelness this is primarily related to physical and/or chemical nonuniformity of the substrate typical examples are barriness in nylon or polyester dyeing and skitteriness in wool dyeing. 

Goncalves IC, Penha S, Matos M et al (2005) Evaluation of an integrated anaerobic-aerobic SBR system for the treatment of wool dyeing effluents. Biodegradation 16 81-89... 

Donnan wool dyeing theory, 26 394 Donohue correlation, 13 262-263... 

The first acid dye, Orange I (1.53 Cl Acid Orange 20), was discovered in 1876. All but a handful of the acid dyes developed since then were evaluated initially with wool dyeing in mind. In terms of adaptability to the coloration of other substrates, however, acid dyes have proved pre-eminent. This is the main reason for their number and variety. As well as the dyeing and printing of nylon and protein fibres, acid dyes are important for the coloration of leather, paper, jute, wood and anodised aluminium. Most of the permitted dyes for food and... 

Hydrolysis of ester groups can also occur in certain wool dyes. For example, Cl Acid Red 1 (3.26) loses its acetyl group (Scheme 3.5) on prolonged dyeing in an acid dyebath, the hue becoming bluer and duller and the dyeing much less fast to light. 

In spite of their long-recognised disadvantages, or as a result of the substantial efforts to overcome them, chrome dyes still represent about 30% of total dye consumption in wool dyeing (Table 3.10 in section 3.2.2). Premetallised acid dyes and reactive dyes for wool account for a further 40%, so it is not surprising that much attention has been given to... 

Traditional wool dyeing methods have often involved a rapid unlevel initial strike at low temperature, followed by a prolonged migration treatment at the boil to attain optimum levelness. To fit in with these requirements, ranges of reactive dyes developed for wool needed to react slowly with the fibre and this implied reactive systems with low intrinsic reactivity. One such group that was found to react too slowly for exploitation on cellulosic... 

S. Ryan, W. Schnitzhofer, T. Tzanov, A. Cavaco-Paulo and G.M. Gubitz, An acid-stable lac-case from Sclerotium rolfsii with potential for wool dye decolorization. Enz. Microbiol. Technol., 33 (2003) 766-774. 

H. Kocaokutgen and S. Ozkinali, Characterisation and application of some o,o -dihydroxyazo dyes containing a 7-hydroxy group and their chromium complexes on nylon and wool. Dyes Pig., 63 (2004) 83-88. 

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