GB674195A - Improvements relating to human hair waving and human hair removing preparations - Google Patents

Abstract

Human-hair waving preparations containing one or more water-soluble salts of mercaptans or of carboxylic thio acids containing one or more SH groups (particularly of thioglycollic acid) have incorporated in them prior to use one or more metal ammine salts which are soluble in ammoniacal solutions but of which the corresponding metal sulphides are insoluble or only sparingly soluble in water, which ammine salts are reactive with hydrogen sulphide at room temperatures. Examples of suitable ammine salts are water-soluble salts of cupro-tetrammine, cadmium-tetrammine, zinc-tetrammine and cobalt-hexammine and complex nickel-ammine salts, zinc-tetrammine being preferred owing to its low toxicity. The proportion of metal ammine salt present in the preparation may range from 0.1 per cent by weight up to the maximum which can be dissolved in the preparation. An example is furnished of a cold wave lotion containing 6.0 per cent by weight of ammonium thioglycollate and 2.0 per cent of ammonia (calculated as NH3), with which is incorporated 3.0 per cent of zinc-tetrammine sulphate and sufficient water to make 100 per cent. In another example a hair-waving solution also intended for use at room temperature contains 5 per cent by weight of the ammonium salt of alpha-mono-thioglycerol, 2.0 per cent of ammonia (calculated as NH3), with which is incorporated 3.0 per cent of zinc-tetrammine sulphate and sufficient water to make 100 per cent. The hydrogen sulphide generated by the reaction with the hair of the thioglycollate or other active ingredient of the preparations converts the ammine salt also present into the corresponding metal sulphide, and the unpleasant odour which would otherwise result during the use of the preparations is thus prevented.