Cleaner coloration of cotton fabric with reactive dyes using a pad-batch-steam dyeing process

To enhance dye fixation rate in pad-steam dyeing, a preliminary research was carried out to examine that the effect of the water content in water-ethanol mixed medium on reactive dyeing of cotton fabrics. The fabric temperature and dyeing properties as affected by the water content were investigated. Based on the results, a batch procedure was incorporated in the pad-steam dyeing to enhance the interactions between reactive dye and cellulosic fibers. The dyeing properties, chemicals and energy consumption of the pad-batch-steam process and conventional pad-steam process were also evaluated. The results show that reducing the water content could expedite fabric heating and improve dyeing properties significantly. The batching time of 60 min, 20 g/L of sodium carbonate and steaming time of 2.0 min were appropriate for dyeing cotton fabric with 25 g/L of C.I. Reactive Violet 5. Compared with conventional pad-steam dyeing, the color strength and dye fixation rates of dyed fabrics using pad-batch-steam dyeing process were maximum increased by 21.4% and 16.1%, respectively. The proposed dyeing process saved 13.7% dye, 33.3% sodium carbonate, 33.3% steam and 28.5% industrial electricity. The pad-batch-steam dyeing process has significant potential for enhancing dye fixation rate and reducing the dyeing effluent, which is a major step towards cleaner dyeing of cotton fabrics.