Pretreatment of cotton to enhance its dyeability;Part 2. Direct dyesS.M. Burkinshaw *, A. GotsopoulosSpecialtyChemical Group, Department of Colour Chemistry, The University, Leeds, LS2 9JT, UKReceived 9 December 1998; accepted 4 January 1999AbstractThree commercial cationic ®xing agents, namely Matexil FC-PN (ICI), Matexil FC-ER (ICI) and Sol®x E (Ciba),originally marketed as aftertreating agents for direct dyes, were used as pretreatments for cotton modi®cation. Pre-treated cotton was dyed with four direct dyes and the eect of pretreatment on the colour strength as well as the washand the light fastness of the dyeings were investigated. The dyeings were also aftertreated with the same agents used forthe 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 elec-trolyte. However, when electrolyte was used, the pretreated samples exhibited generally lower colour strength than thestandard dyeings. The wash fastness of the dyeings was almost unaected by pretreatment while light fastness wasslightly lowered. # 1999 Elsevier Science Ltd. All rights reserved.Keywords: Cotton; Direct dyes; Pretreatment; Enhanced dyability; Low salt dyeing1. Introdu ctionThe pretreatment of cotton with cationic agentsto enhance its dyeability with anionic dyes, such asdirect [1], reactive [2±8] and C.I. Solubilised Sul-phur dyes [9] has attracted interest from manyworkers, especially in recent times. The reasonbehind such pretreatment is that the increasedcationicity imparted to the cellulosic substratereduces the inherent ion±ion repulsion that oper-ates between the anionic dye...
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