ABSTRACT
The reactive dyes (RDs) play an important role among textile dyes in the dyeing of cellulose fbers such as cotton as well as polyamide, wool, and, to a lesser extent silk, fur, and leather.[1] RDs are water-soluble and sold as powders, granules, or water solutions. They produce bright colors, their application is fast, and their fixation is permanent in natural and synthetic fbers.[2] Therefore they are extensively used and there are an enormous number of commercially available products. The RD molecule contains a color-forming component (chromogen) and a fiber-reactive component that form irreversible covalent bonds with the amino acid residues of cellulosic fibers [3] and with hydroxyl groups in the fiber molecule.[4] Because RDs form strong covalent bonds with the fibers to be dyed, they show excellent fastness to washing if the dyeing process is properly done.[5] There are several RDs with different reactive functional groups to which carrier proteins bind to induce immune responses.[6–8] The color-forming component is usually an azo, anthraquinone, or phthalocyanine derivative. Hydrophilic groups improve the water solubility. According to Elliot and Yeung in 1979,[9] functional groups were not less than 23. Some of these were suitable only for either cellulose fibers or wool and nylon, whereas others could be used for any of these materials. According to another report, only dyes belonging to a minority of the existing reactive groups seemed to have been involved in allergic cases. The groups mostly involved were bromoacrylamide, dichlorotriazine, monochlorotriazine, monochlorodifuoro pyrimidine, vinyl sulfone, fluorotriazine, and pyrazolone. The vinyl sulfone RDs are major causes of occupational asthma (OA) and have one or two vinyl sulfone reactive groups.[1,10,11]
