Reactive Dyeing of Cationized Cotton Fabric: The Effect of Cationization Level

Abstract

Modification of cotton fiber with cationic agents is one of the most effective ways to realize its salt-free reactive dyeing. To lay a foundation for the industrial-scale use of the reactive dyeing of cationized cotton fabric, how the level of cationization affects the penetrability of dyes on fabrics and ultimately the dyeing properties were investigated in this study. The results showed that the cationization level of cotton fiber increased with the increasing dosage of 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC), leading to enhanced dye uptake and K/S value. However, an obvious ring dyeing was observed when the cationization level was high and there were many unoccupied cationic sites on the fiber after dyeing. The ring dyeing would result in reduced wet rubbing fastness, and the soaping and washing fastnesses were firstly decreased and then increased with the cationization level. In addition, the optimum cationization level for different reactive dyes was different, and the fastnesses of dyed cationized fabrics at the optimum level were higher than or equal to those of traditional dyeing fabrics.