Conventional Dyeing Process Research Articles

The use of sodium edate in dyeing: II. Union dyeing of cotton/wool blend with hetero bi-functional reactive dyes

Union dyeing of cotton/wool blend with hetero bi-functional reactive dyes, namely CI Reactive Yellow 145, CI Reactive Red 194, and CI Reactive Red 195 is obtained using one-bath and two-bath dyeing processes. The results obtained are compared with those obtained by conventional two-bath dyeing process. Factors affecting the dyeability, such as the amount of sodium edate, sodium sulphate, temperature and dye concentration are investigated. The dyed fabrics were evaluated with respect to the dye exhaustion and fixation, levelling and the fastness properties. Excellent to good fastness was obtained for all samples irrespective of the dyeing method. The result of investigation offers a new viable method for union dyeing by using sodium edate two-bath and one-bath processes with a better levelling and dye uptake.

Alkali-hydrolysis kinetics of alkali-clearable azo disperse dyes containing a fluorosulphonyl group and their fastness properties on PET/cotton blends

The alkali-hydrolysis kinetics of a series of 4-amino-4′-fluorosulphonylazobenzene disperse dyes were investigated using HPLC and their fastness properties on PET/cotton blends were examined. Most of the dyes showed reasonable level of hydrolysis (%) under relatively mild alkaline condition and the dyes having more electron-accepting group in diazo component exhibited lower rate of hydrolysis. The application of fluorosulphonyl containing disperse dyes on PET/cotton blends showed excellent dyeing fastness properties and offers the option of one-bath dyeing process, replacing time- and energy-consuming conventional two-bath dyeing process.

Adsorption behavior of direct dye on cotton in non-aqueous media

Solubilization and adsorption behavior of direct dye on cotton in Aerosol-OT (AOT) revere micellar system has been investigated. Cotton fabrics could be dyed in deep shade with direct dye from reverse micellar system without adding auxiliaries. Exhaustion of dye was almost perfect and was very superior to that in aqueous system. High exhaustion of the dye in reverse micellar system was attributed to the very low bath-ratio (water–fabric ratio) compared to the conventional aqueous dyeing process. It has become obvious that adsorption of direct dye on cotton in reverse micellar system is similar to that in aqueous system and follows a Freuindrich manner.