One-Bath One-Step Dyeing of a Polyester/ Cotton Blend using the Pad-Dry-Fixation Process

The aim of this research work was to evaluate the one bath dyeing of polyester/cotton blend and to compare the results with those of two bath dyeing. Polyester/cotton (50:50) blend fabrics were studied using dichlorotriazine based reactive dye and compatible disperse dye. The one bath one step method was used to shorten the dyeing process, increase yield and reduce the utility and chemical cost. Trichloroacetic acid (TCAA) was used to provide an acidic and basic medium with a change in temperature. A TCAA/sodium carbonate buffer was also used to obtain the best colour yield. In two bath dyeing disperse dye was fixed on polyester fibre in an acidic medium, whereas reactive dye was fixed on cellulosic fibre in an alkaline medium. In the final stage, the dyed fabric was evaluated by testing the light, washing and rubbing fastness and colour yield strength properties of the dye. The results clearly show that polyester/cotton fabric presents good fastness and colour strength values when the one bath one step dyeing method is used.