Improving the Environmental Aspects of Sulphur Dyeing of Cotton Knitted Fabrics

Abstract

ABSTRACT An attempt has been made to search for an eco-friendly reductants and oxidants for complete substitution of the hazardous ones along with finding out proper conditions for attaining better knitted sulphur dyeings. The results detailed in this article indicate that a) the extent of coloration is governed by both the type of reductant as well as dye/reductant ratio, i.e. liquid glucose (LG, ratio 1/1) > glucose (G, ratio, 1/1) > molaas (M, ratio 1/4), as well as the knitted fabric structure i.e. Pique > Rib > Milton; (b) the depth of shade can be improved by raising the dyeing temperature up to 80°C for 45 min., at a material-to-liquor ratio 1/10, in presence of 30g/l common salt; (c) the extent of sulphur dyeing is determined by the nature of oxidant, i.e. (NH4)2S2O8 > H2O2 > None; (d) after treatment with cationic softener results in higher softness along with better washing and rubbing fastness; and (e) the dyeing as well as fastness properties of the obtained sulphur dyeings depend on the sulphur dye category.