Natural Dyeing of Jute Fabric with Catechu

摘要

Standard 3% H_2O_2 bleached jute fabric, pre-mordanted with selective single and double mordants using myrobolan (harda/haritaki) and metallic salts has been dyed with aqueous extract of Catechu (a natural dye). Changes in importantmechanical properties after mordanting and corresponding dyeing behavior have been evaluated in terms of instrumentally measured colour interaction parameters. 20-30% myrobolan (Harda) followed by 20-30% of Al_2(SO_4)_3 pre-mordanting treatment in sequence have been found to be the most potent double mordanting systems rather than corresponding individual single mordant used. With this selective dye-fibre mordant system, dyeing process variables have also been standerdised. Effects of dyeing process variables on surface colour strength and dye uniformity in the present study have indicated that the 60 min dyeing time, 90℃ dyeing temperature, 12 pH, 1:5 material-to-liquor ratio, 20 -30% mordants concentration for each of the double mordant system, 50% (on the weight of solid source material) dye concentration (Catechu), and 15 gpl common salt have been found to be the optimum dyeing condition. Colour fastness properties to washing, rubbing and light as well as dyeing-pH sensitivity for selective fibre-mordants-dye systems on colour fastness properties have also been assessed and reported. Improvement of wash and light fastness had also been achieved with specific eco-friendly chemicals for popularizing the same in export market.