Exhaust dyeing of polyester-based textiles using high-temperature-alkaline conditions

The factors affecting the dyeability of polyester-based textiles with disperse dyes in an alkaline medium were studied. It was found, for a given set of dyeing conditions, that (a) the appropriate conditions for attaining a higher color yield were 45 min at 130degreesC with pH 9 using a material-to-liquor ratio of 1/10; (b) increasing the Diaserver(R) AD-95 concentration to 2% ows (based on weight of substrate) as well as including triethanolamine to 2% ows in the dyeing formulations bring about a significant improvement in the dye uptake; (c) both a preheat setting from 160 to 200degreesC/30 s and an alkaline weight reduction have a positive impact on postdyeing with the used disperse dye; (d) the extent of dye uptake as well as the color strength are governed by the type of substrate, that is, knitted fabric > spun yarn > woven fabric, nature of the dye stabilizer, that is, EDTA > Diaserver(R) AD-95 > Tinoclorite(R) CBB > citric acid > none, as well as kind of the disperse dye; (e) direct reuse of the disperse dyebaths, without reconstitution, in the dyeing of the used substrates was shown to be feasible in a single shade and in the reverse-order dyeings (dark light); (f) one-bath, one-step exhaust dyeing of polyester/cotton-knitted fabric using selected disperse reactive dyes combinations under high-temperature alkaline conditions is feasible; and (g) the color and fastness properties of the resultant dyeings depend on the type of the used auxiliaries, in addition to the nature of disperse/reactive dyes combinations as well as compatibility with other ingredients. (C) 2003 Wiley Periodicals, Inc.