Effect of pretreatments on ambient temperature bleaching and reactive dyeing of jute

Abstract

Bleaching of grey jute yarn by conventional hot hydrogen peroxide bleaching, ambient temperature bleaching and ambient temperature bleaching using spent liquor has been studied. Before bleaching, the jute yarns were either scoured or

treated with alkali at ambient temperature. One set of alkali-treated jute yarns was washed, dried and then used for bleaching and the other set of alkali-treated yarns was dried without washing and used for bleaching. All the bleached samples were dyed at room temperature using cold brand reactive dye. It is found that the whiteness and brightness indices of the jute yarn samples bleached by conventional process follow the older: grey bleached >scoured and bleached > alkali-treated (without wash) and bleached> alkali-treated (with wash) and bleached. For ambient temperature bleached samples, the order is : grey bleached > scoured and bleached> alkali-treated (with wash) and bleached > alkali-treated (without wash) and bleached . The dye uptake value increases with the following order of pretreatments: alkali-treated (without wash) > alkali-treated (with wash)> scoured > grey.