To improve the deep dyeing of cellulosic fibers, the existing conventional dyeing process requires the addition of high amount of salts. The dyeing wastewater containing disposal salts could result in a negative impact on environmental ecology. It is a high cost and energy consumption process to treat the dyeing wastewater.To meet the concern and increasing demands for environmental quality, the current research trend of cellulosic fiber dyeing process is aimed at the salt-free or low-salt dyeing process.
This study was based on the methodology of creating a cationization on cellulosic fiber by using epoxy-based quaternary ammonium salt as a modifier. The dyeing process of modified cellulose fiber was carried out with acidic and reactive dyes, respectively. The effects of varying the dyeing conditions were investigated. The optimum dyeing condition was established. The experimental data demonstrated that the promising result could be obtained by carried out the B dyeing process, adding the liquid caustic soda and then adding modifiers, at the temperature of 95 °C . The investigation of the optimum dyeing process resulted in the finding of salt-free effect of dyeing cellulosic fiber by acidic dye. The resulted dyeing depth was improved to be five times over the conventional process. The resulting of low-salt reactive dyeing process leaded to the reduced amount of 75% of Glauber’s salt consumption. No significant change in the color fastness properties of washing and friction is observed comparing with conventional process.
