Aftertreatment of Conventional Direct Dyeings of Cotton with a Bis‐reactive Cationic Fixing Agent

Abstract

A bis-reactive cationic fixing agent, ethylenebis [N-(2,3-epoxypropyl)-N,N-dimethylammonium chloride] has been used as an aftertreatment reagent to improve the wash fastness of direct dyes on cotton. The effects of different pH conditions and concentrations on the effectiveness of this cationic fixing agent have been investigated. The results showed that aftertreatment at pH 11 produced dyeings with higher colour strength and better wash fastness than that at pH 7. In addition, the cationic agent at a low concentration was found to be more effective under both neutral and alkaline conditions.

Synthesis of a Bi-functional Cationic Agent and its Application in Cotton Dyeing

“…Epichlorohydrin was then added slowly with continuous stirring; the temperature was maintained at 40 ± 5 °C and the reaction mixture was stirred for 10-12 h. e mole ratio of TEMED: HCl: epichlorohydrin was 1:2:2. e bi-functional cationic agent (CA1) was a yellowish, viscous liquid with 77.2% solid content. 16,17…”