Patent GB-1092868-A (GB)
Title: Metal cleaning
IPC: C23G1/02
Filed: 1964-11-19
Abstract: A water soluble detergent composition for cleaning metal articles comprises a metal oxide removing acid, a hydrogen embrittlement inhibitor and a balanced surfactant composition comprising a mixture of surfactants with the properties of metal melting, oxide detergency, oil emulsification and dirt dispersion, at least two of the surfactants having different molecular weights and an HLB value of 12-17 and another of the surfactants having an HLB value of 1-5. A further surfactant with an HLB value greater than 17 is also preferably present. Suitable acids are: sulphuric, phosphoric, tartaric, citric, diglycolic, chlorosulphonic, formic, acetic and mono-, di- or tri-chloroacetic acids.  When strong inorganic acids are used carbon emitting is prevented by the addition of salts such as sulphates of Sn, Pb, Cd and Hg. Acid salts of mineral acids, e.g. sodium bisulphate or monobasic sodium phosphate, or salts which hydrolyse, e.g. aluminum chloride or ammonium sulphate may also be used as the acid source.  Each of the surfactants has a hydrophobic polyoxypropylene nucleus and hydrophilic polyoxyethylene units graft polymerized thereon.  N,N-ethoxylated unctuous nitrogenous compounds such as coco amide which is N,N-substituted with 15 mols of ethylene oxide to form a cationic surfactant or hydrogenated tallow amide which is N,N-substituted with 15 mols of ethylene oxide to form a non-ionic surfactant may also be added. The hydrogen embrittlement inhibitors may be polyoxyethylene glycol, o-toluidene, an adduct of o-toluidene and formaldehyde, ethylene oxide modified rosin amine, 1-hexyn-3-ol, substituted thioureas, and amides or proteins.ALSO:A water soluble detergent composition for cleaning metal articles comprises a metal oxide removing acid, a hydrogen embrittlement inhibitor and a balanced surfactant composition comprising a mixture of surfactants with the properties of metal melting, oxide detergency, oil emulsification and dirt dispersion, at least two of the surfactants having different molecular weights and an HLB value of 12-17 and another of the surfactants having an HLB value of 1-5. A further surfactant with an HLB value greater than 17 is also preferably present.  Suitable acids are: sulphuric, phosphoric, tartaric, citric, diglycolic, chlorosulfonic, formic, acetic and mono-, di- or tri-chloroacetic acids.  When strong inorganic acids are used carbon smutting is prevented by the addition of salts such as sulphates of Sn, Pb, Cd and Hg. Acid salts of mineral acids e.g. sodium bisulphate or monobasic sodium phosphate, or salts which hydrolyze e.g. aluminium chloride or ammonium sulphate may also be used as the acid source.  Each of the surfactants has a hydrophobic polyoxypropylene nucleus and hydrophilic polyoxyethylene units graft polymerized thereon. N, N-ethoxylated unctuous nitrogenous compounds such as coco amide which is N, N substituted with 15 mols of ethylene oxide to form a cationic surfactant or hydrogenated tallow amide which is N, N substituted with 15 mols of ethylene oxide to form a non-ionic surfactant may also be added. The hydrogen embrittlement inhibitors may be polyoxyethylene glycol, o-toluidene, an adduct of o-toluidene and formaldehyde, ethylene oxide modified rosin amine, 1-hexyn-3-ol, substituted thioureas, and amines or proteins.