GB970950A - Bleaching and detergent compositions - Google Patents

Abstract

A composition suitable for use in the washing and bleaching of textiles comprises an inorganic per-salt and an ester of carbonic or pyrocarbonic acid which when tested as described below, has a titre of not less than 1 ml. 0.1N Na2S2O3. The test is carried out by adding the ester to 500 ml. of an aqueous solution containing 1.25 gms. sodium pyrophosphate and 0.154 gms. sodium perborate at 60 DEG C. in an amount in equimolecular ratio to the available oxygen; after one and five minutes 100 ml. portions of the solution are withdrawn and pipetted on to a mixture of 250 gms. of cracked ice and 15 ml. of glacial acetic acid, 0.4 gm. of potassium iodide is added and the liberated iodine titrated with 0.1N sodium thiosulphate, using starch as indicator. The ester may be one having the formula R1 O.CO. OR2 in which R1 is a radical that exerts an electron attracting effect and R2 is an alkyl, aryl or alicyclic radical which may be substituted, specified esters being sodium p-sulphophenyl ethyl carbonate, sodium p-sulphophenyl methyl carbonate, sodium p-sulphophenyl phenyl carbonate, diethyl pyrocarbonate, o- or p-carboxy phenyl ethyl carbonate, o- or p-carboxy phenyl methyl carbonate, p-carboxy phenyl phenyl carbonate, p-carboxy phenyl n-propyl carbonate, p-carboxyphenyl-n-butyl carbonate, benzyl p-carboxy phenyl carbonate, sodium p-sulphophenyl n-propyl carbonate, sodium p-sulphophenyl n-butyl carbonate and sodium p-sulpho phenyl benzyl carbonate. The detergent present in the composition may be soap, sodium dodecylbenzene sulphonate, an alkyl sulphate or a salt of an ester or ether of isethionic acid and the inorganic persalt may be an alkali metal perborate, percarbonate, perpyrophosphate or persilicate. The composition may also contain inert salts, e.g. alkali metal sulphates and chlorides, alkaline materials, e.g. alkali metal carbonates, ortho phosphates, tripoly phosphates and pyrophosphates and silicates, in an amount sufficient to give the washing and bleaching solution a pH of 9-11 before addition of the ester, carboxy methyl cellulose, coconut monoethanolamide and fluorescent brightening agents.ALSO:Textiles, e.g. cotton cloth, are bleached by treating them with an aqueous solution of hydrogen peroxide and an ester of carbonic or pyrocarbonic acid which when tested as described below, has a titre of not less than 1 ml 0.1N Na2S2O3. The test is carried out by adding the ester to 500 ml of an aqueous solution containing 1.25 gms sodium pyrophosphate and 0.154 gms sodium perborate at 60 DEG C. in an amount in equimolecular ratio to the available oxygen; after one and five minutes 100 ml portions of the solution are withdrawn and pipetted on to a mixture of 250 gms of cracked ice and 15 ml of glacial acetic acid, 0.4 gm of potassium iodide is added and the liberated iodine titrated with 0.1N sodium thiosulphate, using starch as indicator. The ester may be one having the formula R1 O. CO. OR2 in which R1 is a radical that exerts an electron attracting effect and R2 is an alkyl, aryl or alicyclic radical which may be substituted, specified esters being sodium p-sulphophenyl ethyl carbonate, sodium p-sulphophenyl methyl carbonate, sodium p-sulphophenyl phenyl carbonate, diethyl pyrocarbonate, o- or p-carboxy phenyl ethyl carbonate, o- or p-carboxy phenyl methyl carbonate, p-carboxy phenyl phenyl carbonate, p-carboxy phenyl n-propyl carbonate, p-carboxy phenyl-n-butyl carbonate, benzyl p-carboxy phenyl carbonate, sodium p-sulphophenyl n-propyl carbonate, sodium p-sulphophenyl n-butyl carbonate and sodium p-sulphophenyl benzyl carbonate. The solution may be prepared by dissolving a solid composition comprising an inorganic persalt, e.g. an alkali metal perborate, percarbonate, perpyrophosphate or persilicate, and the ester of carbonic or pyrocarbonic acid in water. The composition may also contain inert salts, e.g. alkali metal sulphates and chlorides, detergents, e.g. soap, alkylaryl sulphonates, alkyl sulphates and salts of esters or ethers of isothionic acid, alkaline materials, e.g. alkali metal carbonates, ortho phosphates, tripoly phosphates and pyrophosphates and silicates, in an amount sufficient to give the treating solution a pH of 9-11 before addition of the ester, carboxy methyl cellulose and fluorescent brightening agents.