GB774521A - Improvements in or relating to the removal of tarnish from silver articles - Google Patents

Abstract

An agent for use in the detarnishing and polishing of silver and silver alloys comprises an acid stronger than hydrosulphuric acid but which is not such as will in aqueous solution attack silver to any material extent, at least 1.0 per cent of a soluble compound capable of forming a soluble complex with silver ions which complex gives rise to substantially no silver ions in aqueous solution, said soluble compound fulfilling both of the tests specified in the parent Specification, and means providing polishing and/or mild abrasive action on silver, said means being substantially stable to the acid present (in aqueous solution). The acid may be hydrochloric, sulphuric, aminosulphonic, chloracetic, tartaric or citric acid, the complex-forming compound may be thiourea or thiosemi-carbazide, and the polishing &c. means may be one or more of diatomaceous earth, titanium dioxide, rouge, powdered silica kieselguhr and abrasive silicates, e.g. a polishing clay or calcium silicate. The agent may be in the form of (a) a liquid, when there may be added detergents having thickening properties, e.g. 1 per cent of a mixture of 95 per cent C16 and 5 per cent C18 amine hydrochlorides, colloidal suspending agents such as carboxy methyl cellulose, a wetting agent, a buffer, e.g. aluminium chloride, a solubilized perfume, and a non-toxic, non-volatile germicidal agent such as a cationic quaternary ammonium compound, or (b) a dry mix, when there may be added a solid detergent, perfume &c., said mix being applied in the presence of water either by being made into a paste therewith or by impregnation in a polishing cloth.ALSO:An agent for use in the detarnishing and polishing of silver and silver alloys comprises an acid stronger than hydrosulphuric but which is not such as will in aqueous solution attack silver to any material extent, at least 1.0 per cent of soluble compound capable of forming a soluble complex with silver ions which complex gives rise to substantially no silver ions in aqueous solution, said soluble compound fulfilling both of the tests specified in the parent Specification, and means providing polishing and/or mild abrasive action on silver, said means being substantially stable to the acid present (in aqueous solution). The acid may be hydrochloric, sulphuric, aminosulphonic, chloracetic, tartaric or citric acid, the complex-forming compound may be thiourea or thiosemic carbazide, and the polishing etc. means may be one or more of diatomaceous earth, titanium dioxide, rouge, powdered silica, kieselguhr and abrasive silicates, e.g., a polishing clay or calcium silicate. The agent may be in the form of (a) a liquid, when there may be added, detergents having thickening properties, e.g., 1 per cent of a mixture of 95 per cent C16 and 5 per cent C18 amine hydrochlorides, colloidal suspending agents such as carboxy methyl-cellulose, a wetting agent, a buffer, e.g. aluminium chloride, a solubilized perfume, and a non volatile, non-toxic germicidal agent such as a cationic quaternary ammonium compound, or (b) a dry rinse, when there may be added a solid detergent, perfume &c., said mix being applied in the presence of water either by being made into a paste therewith or by impregnation in a polishing cloth.