A study on salt free reactive dyeing of cotton materials using exhaust application of cationic agent

Abstract

In the present day there are a variety of fibres available for apparel production and cotton based apparels remain treasured for their natural feel look and comfort properties Although cotton woven structures occupy a special position in the production of apparel and garment wears today the demand for cotton knitted structures in manufacturing of apparels has tremendously increased ranging from intimate wear to sportswear to outer wear For cotton knit based apparels fibre reactive dyes are colourant of choice because of their brilliance brightness variety of hues and ease of application In addition to that these dyes are chemically bonded to the fabric resulting in a high wet fastness to the fabric But the usage of reactive dyes is accompanied by usage of large amounts of salt to exhaust the dyes and alkali to fix the dyes on the fabric Even with the required amount of salt only 60 65 of reactive dyes are exhausted remaining 35 40 of dyes along with added salt are removed as a coloured effluent after dyeing In addition to that reactive dyeing process consumes excessive amounts of water to remove the unutilized dyes from the fabric and generate huge quantities of effluent at the end of the dyeing process The adoption of zero liquid discharge treatment system for the discharged effluent is a time consuming energy intensive and costly process Modification of the cotton dyeing show significant environmental benefits but in many cases those processes required extensive capital investment and time in order to be beneficial to the industry. newline