ES343312A1 - Process for bleaching textiles - Google Patents

Abstract

and DIP. Textiles, e.g. cotton fabric, are bleached by impregnating them with an aqueous solution of sodium and/or calcium hypochlorite at a pH of 7-12 and such that the pickup of hypochlorite bleaching agent by the textiles is from 0.05-1%, calculated in terms, of active chlorine by weight of the textiles and then subjecting them to steam treatment at a temperature of 50 -140 C for 15-60 seconds in a steamer or pressure vessel. The textile which may be in the scoured or desized state may be impregnated at room temperature with the solution of the hypochlorite which may also contain a wetting agent, a chelating agent, e.g. ethylene diamine tetra-acetic acid or diethylene triamine pentaacetic acid, sodium chlorite or bromite or catalyst and/or accelerator, squeezed to the required pick-up of bleaching agent, optionally preheated using steam, infra-red or direct heat radiations, and then heated with steam which may be saturated or superheated. After steaming the textile may be washed and dried by means of a series of heated cylinders or a hot air chamber. In Fig. 2 the textile 10 is passed around rollers 11 in impregnation chamber 1 and passed by rollers 12 and 13 to preheating chamber 2 where it passes over rollers 14 and is conveyed to steaming chamber 3 where it passes over rollers 16 and is passed by rollers 17 to a second impregnating chamber 1A and second steaming chamber 3A where it passes over rollers 19 and is finally bleached. It is then passed through rollers 20 to a washing machine having compartments 5, 6 and 7 having a series of rollers 21 for passage of the textile therethrough and rollers 22 and 23 for nipping and is passed over rollers 24 to drying means 8 comprising a series of heated rollers 9 and is taken off on roller 25.