Cassia tora Gum- A Thickener for Screen Printing on Silk with Kachnar Bark Dye

Abstract

The art of printing with natural dyes has played an important role in beautifying the textiles, since time immemorial. But with the introduction of synthetic dyes the use of natural dyes gradually went out of existence due to the fact that brilliant colour and shades with good fastness can be produced with synthetic dyes in lesser time. With the increased awareness of people about harmful effects of synthetic dyes, use of natural dyes as an alternative source again geared up. Nowadays fabrics dyed and printed with natural dyes are in more demand amongst the green minded and health conscious consumers. Keeping in view the importance of natural dyes in textile world a study was conducted to print silk fabric with kachnar bark dye using Cassia tora gum. Eight percent dye was extracted by boiling in water and strained to get dye extract. Extracted dye was evaporated to make 10 ml. dye concentrate. Two concentrationsi.e. 2.5 and 5 % of Cassia tora gum powder was used as natural thickener. Copper sulphate and ferrous sulphate were used as mordants. Printing was done by screen printing technique. Printed samples were dried in sun, cured for three days and steamed in laboratory steamer. The printed samples were evaluated visually for depth of colour, evenness of print, sharpness of print and overall appearance.Fastness of printed samples was studied against, sunlight, washing, rubbing and perspiration using standard test methods. Good prints were obtained with screen. Results of the study revealed that for visual evaluation all the printed samples scored very good scoring 3.82 to 4.4. The fastness ratings against different agencies ranged from fairly good (3/4) to excellent (5). The fastness as well as visual evaluation grades of Cassia tora gum were comparable with guar gum used as controlled thickener, hence cassia tora gum can be used effectively for printing of silk.