Pretreatment of cotton to enhance its dyeability; Part 2. Direct dyes

Three commercial cationic fixing agents, namely Matexil FC-PN (ICI), Matexil FC-ER (ICI) and Solfix E (Ciba), originally marketed as aftertreating agents for direct dyes, were used as pretreatments for cotton modification. Pretreated cotton was dyed with four direct dyes and the effect of pretreatment on the colour strength as well as the wash and the light fastness of the dyeings were investigated. The dyeings were also aftertreated with the same agents used for the pretreatment, and their wash fastness properties were compared with those of the aftertreated standard dyeings. Pretreatment was found to increase the colour strength of the dyeings when dyeing had been carried out without electrolyte. However, when electrolyte was used, the pretreated samples exhibited generally lower colour strength than the standard dyeings. The wash fastness of the dyeings was almost unaffected by pretreatment while light fastness was slightly lowered.