Improving the dyeability of natural colorants on cotton by cationization

Abstract

Cotton fabric was cationized with several cationizing reagents before dyeing with natural colorants (Redwood, Gromwell, Cochineal, Goldthread and Amur cork tree) for improving its dyeability. The K/S value of cationized cotton fabric dyed with Redwood and Cochineal was higher than that of untreated one. In case of Gromwell, though the K/S value of the cationized fabric was higher than that of untreated one, the fabric showed poor levelness. Cationization of cotton had no effect on the dyeability of Goldthread and Amur cork tree. It is observed that when the concentration of NaOH exceeds beyond a certain level, NaOH hydrolyzes the cationizing agent and the K/S values of dyed materials decrease. The optimum concentrations of NaOH in cationization have been determined for dyeings with different natural colorants.