Volume 1 Issue 3
Single Stage Application of Disperse/Reactive Dye System on Chemically Modified Polyester/Cotton Blend for Improved Performance
Wet processing of textiles involves utilization of large amount of chemicals, which ultimately adds to effluent load. The colouration of textiles with various dyes makes the colour of the effluent dark and hence requires expensive treatments for the removal of dyes from the effluent. In the present work, a blend comprising of polyester and cotton components was dyed with disperse and reactive dyes respectively by a neutral dyeing approach. Normally polyester is dyed with disperse dyes in acidic medium, while cotton is dyed with reactive dyes in an alkaline medium for their respective fixation; the application involves either a two bath or one bath/ two-step dyeing procedure to be employed. In this approach, the blend was pretreated with a potential polymer, polyacrylic acid, in the presence of a suitable cross-linking agent and subsequently the pretreated fabric was dyed by pad-dry-cure dyeing technique using both disperse and reactive dyes in the same padding liquor in the absence of any chemical in the bath. Thus, one bath/one-step dyeing method was possible with such neutral dyeing method leading to considerable saving of energy, time, water, labour, etc. These dyeing were compared with the conventionally dyed samples in terms of colour strength (K/S) values, measured on spectrophotometer. The washing, light and rub fastness of the dyed samples were quite good and comparable with the conventionally dyed samples. Effluent characteristics show remarkable results for the new approach and since chemicals were not utilized during dyeing, the pH, BOD, COD, etc. were all in the permissible range, indicating no extra effluent treatment to be used, except removal of dyes/colour from the effluent by a suitable colour removable technique, Thus, the new approach may be considered as “Green processing of cellulosic textiles” without any pollution problem.
Reactive dye, polyacrylic acid, cross-linking, effluent characteristics, green processing