A study of washing-off stage for cotton dyed fabrics by reactive dye and their effect on fastness to wet treatments

A reactive dye was applied to woven cotton fabric then washed-off using water and three alkaline agents (ammonium hydroxide, sodium bicarbonate, sodium hydroxide). The aim of washing-off is to eliminate of dyes no fixed on fabric to avoid its dissolution during washing what reduces fastness to washing. The duration and temperature of wash-off were fixed, and the concentrations of alkaline agents used were varied, and the effects of these variables on the wash fastness of the dyeing were determined. There was little difference between the three alkaline agents, in terms of the level of wash-fastness achieved. The best result was with sodium bicarbonate and sodium hydroxide