GB992954A - Improvements in or relating to bleaching - Google Patents

Abstract

An aqueous alkaline chlorite-containing bleaching concentrate or an alkaline chlorite containing bleaching solution contains a stabilizing and activating quantity of urea and/or one or more of ammonium carbonate, bicarbonate or carbamate. The term a "stabilizing and activating quantity" means such a quantity that the chlorite containing solution or concentrate is stable in contact with it under normal storage conditions and is activated by it on heating. The bleaching concentrate contains at least 200 g/l of chlorite and preferably contains 10-80 g.p.l. of the additive. The bleaching solution preferably contains 0.5-5 g.p.l. of the additive. The chlorite may be sodium, potassium, ammonium or calcium chlorite. The bleaching concentrate or solution may also contain wetting agents, e.g. nonyl-phenyl-polyethylene glycol ether containing 4 molecules of ethylene oxide per molecule and the sodium salt of di-isobutyl naphthalene sulphonic acid, corrosion preventatives, e.g. sodium nitrate, buffer substances, e.g. di-sodium hydrogen phosphate, and optical bleaching agents, e.g. stilbene and coumarin derivatives. Textile materials, e.g. cotton, polyester, viscose rayon, cellulose acetate rayon and polyamide fabrics, may be bleached by contacting them with the bleaching solution, separating the bulk of the bleaching solution from the textile materials and then heating the textile materials, if desired while they are stored in a closed polythene bag.