GB704576A - Detergent compositions - Google Patents

Abstract

A minor proportion of a dibutyl thiourea is added to detergent compositions to inhibit their tarnishing action on metals, such as German silver. The detergent composition may contain or comprise water-soluble inorganic polyphosphates, such as hexasodium hexametaphosphate, hexasodium tetraphosphate or the alkali metal or ammonium salts of tripolyphosphoric tetraphosphoric or pyrophosphoric acids, and/or synthetic organic detergents. The latter include the anionic sulphated and sulphonated detergents such as the sulphates of aliphatic compounds having, preferably, 12 to 26 carbon atoms in the molecule, and more particularly those having an acyl radical of about 8 to 22 carbon atoms. Such compounds include the sulphuric acid esters of polyhydric alcohols incompletely esterified with higher fatty acids, e.g. coconut oil monoglyceride monosulphate and tallow diglyceride monosulphate; the pure or mixed higher alkyl sulphates, e.g. lauryl sulphate, cetyl sulphate and those derived from reduced coconut oil fatty acids; the hydroxy sulphonated higher fatty acid esters, e.g. higher fatty acid esters of 2.3 dihydroxy-propane sulphonic acid; the higher fatty acids esters of alkylol sulphonic acids, e.g. oleic ester of isethionic acid; the higher fatty acid ethanolamide sulphates and the higher fatty acid amides of amino alkyl sulphonic acids, e.g. lauric acid tauride. The synthetic organic detergent may also be an alkyl aryl sulphonate wherein the nucleus may be derived from benzene, toluene, xylene, phenol, cresols or naphthalene, and the alkyl groups may have 8 to 22 and preferably 12 to 16 carbon atoms. These anionic detergents are generally employed in the form of their water-soluble salts such as alkali metal, alkaline earth metal, magnesium ammonium, amine or alkylolamine salts. The synthetic organic detergents may also comprise non-ionic detergents such as the polyoxyethylene ethers of alkyl phenols or of long chain aliphatic alcohols, and ethers of polyalkylene glycols. The inhibitor may be a symmetrical N.N1-(or 1.3)-dibutyl thiourea in which the butyl may be normal, secondary or isoin structure. The amount of inhibitor added is normally less than 1 per cent. by weight of the total composition and preferably up to 0.5 per cent., e.g. 0.05 to 0.5 per cent. These quantities are particularly effective for use with built detergent compositions containing from 10 to 50 per cent and preferably 15 to 40 per cent. by weight of a synthetic organic detergent, preferably of the anionic sulphated or sulphonated type, and about 10 to 80 per cent. and usually 20 to 60 per cent. by weight of the polyphosphates. The compositions may contain other additives such as alkali metal phosphates, silicates, sulphates, chlorides, hydroxides and carbonates, sodium carboxymethylcellulose and fatty acid amides, alcohols or esters.ALSO:A minor proportion of a dibutyl thiourea is added to detergent compositions to inhibit their tarnishing action on metals, such as German silver. The detergent composition may contain or comprise water-soluble inorganic polyphosphates, such as hexasodium hexametaphosphate, hexasodium tetraphosphate or the alkali metal or ammonium salts of tripolyphosphoric, tetra-phosphoric or pyrophosphoric acids, and/or synthetic organic detergents. The latter include the anionic sulphated and sulphonated detergents (see Group III). The synthetic organic detergents may also comprise non-ionic detergents such as the polyoxyethylene ethers of alkyl phenols or of long chain aliphatic alcohols, and ethers of polyalkylene glycols. The inhibitor may be a symmetrical N.N1 or 1.3 dibutyl thiourea in which the butyl may be normal, secondary or isoin structure. The compositions may contain other additives such as alkali metal phosphates, silicates, sulphates, chlorides, hydroxides and carbonates, sodium carboxymethylcellulose and fatty acid amides, alcohols or esters.