Mercerisation Followed by Wet on Wet Reactive Dyeing of Cotton Fabric

Abstract

The commonly employed textile wet processing methods are singeing, de-sizing, scouring, bleaching, mercerising, dying, printing, and finishing. However, these methods are more time-consuming and require a lot of energy, manpower, and chemicals. Therefore, this research aims to develop a semi-continuous processing route that minimizes these problems. In this study, two dying routes were employed. The first is a control group, which was done by conventional mercerisation and dyeing procedures, whereas the second is a semi-continuous experimental group, which has been employed by mercerisation followed by wet-on-wet (WOW) reactive dying. That is, after mercerisation, the fabric, which contains the optimum alkali concentration, goes to dyeing without washing. Washing and titration were performed to determine the optimum alkaline concentration in the fabric at a specific washing cycle. Fabrics that were washed at different cycles after mercerisation were dyed, and their washing fastness, degree of dye exhaustion, fixation, and colour strength were evaluated, and they had a slightly greater colour strength than conventionally dyed fabrics. This is because with a wet-on-wet dyeing procedure, the fabric is relaxed after mercerisation, which allows it to absorb more dye, and the leftover alkali in the fabric is used to fix the dye to the cellulose. The study shows that the optimal washing cycle for passing the optimum alkali concentration is one. Furthermore, the optimal amount of alkali remaining in the fabrics is 3–3.5%. As compared to the conventional dyeing process, this process is economical.