The effect of pretreatment on the environment and dyeing properties of a selected cotton knitted fabric

The current preparation of cotton knitted fabric prior to dyeing mainly involves a combined process consisting of scouring and peroxide bleaching. In this research two pre-treatment procedures, i.e. combined alkaline scouring/bleaching and enzymatic scouring/bleaching, were compared and their effects evaluated regarding environmental impact, whiteness and dyeing properties. Different pre-treated samples of cotton knitted fabrics were subsequently dyed with a chosen set of bifunctional reactive Cibacron LS dyes. The results obtained indicate that combined pre-treatment by enzymatic scouring/bleaching can be regarded as a good alternative to alkaline scouring/bleaching since it results in lower pollution of waste-water lower SAK value after dyeing, washing and soaping, and consequently lower hydrolysation of dyestuff. Furthermore, added advantages are that it produces similar whiteness, similar dye exhaustion and, with the exception of black dyestuff comparable dyeing results.