SUSTAINABLE AND ENERGY-EFFICIENT DYEING OF HOT BRAND REACTIVE DYES ON COTTON SUBSTRATE
Bipin J. Agrawal
ABSTRACT - Energy conservation is the basic requirement in the present scenario when the entire world is facing energy crisis. The chemical wet processing of textiles consumes large amount of energy since most of the processes, including pretreatments, dyeing, printing and finishing are performed at considerably high temperatures. The cost of energy is continuously increasing and is becoming a significant share of the total cost of processing textiles. Among various wet processing operations, the dyeing process consumes more than 50 % of energy. Therefore, it is essential to design various techniques so as to reduce the energy consumption during dyeing. Lowering the temperature during dyeing is one such aspect which substantially minimizes the energy requirements. The present work aims to develop conditions suitable for the application of bis-monochloro–s-triazine (HE, hot brand) reactive dyes, on cotton substrates at low temperatures. The feasibility of reactive dyeing of cotton fabrics with HE reactive dyes at low temperature was carried out in the presence of a swelling agent (tri-ethanolamine) in conjunction with an alkali. Both conventional and swelling agent-assisted dyeings were performed in the presence of the same alkali, viz. sodium carbonate. The colour strength values of the dyed samples were evaluated spectrophotometrically and were compared with conventionally dyed samples. The fastness characteristics, viz. wash, light and rub fastness were also assessed by standard measurement techniques for commercialization of the modified low-temperature dyeing technique.
Keywords: hot brand reactive dye, swelling agent, low-temperature dyeing, colour strength, fastness characteristics