Patent GB-835927-A (GB)
Title: Germicidal article
Inventor: HILL WILLIAM HERMANN
IPC: D06M16/00
Filed: 1957-03-12
Abstract: Cotton, wool, nylon or rayon fabrics, yarns or bolts of cloth and articles such as bedding, clothing, towels, and bandages are impregnated or coated with silver thiocyanate, to impart bactericidal properties to the materials.  A coating may be obtained by precipitating the salt upon the surface of the article treated, or by applying an aqueous emulsion of a binder, e.g. polyvinyl acetate, having the salt dispersed therein, e.g. by precipitation from a solution containing silver thiocyanate and ammonia or another colourless thiocyanate.  The treatment of cellulosic fibres may be accompanied by swelling and penetration of the salt within the fibres.  The articles may be impregnated and/or coated by applying an aqueous solution containing silver thiocyanate and ammonia or sodium, ammonium or calcium thiocyanate as solubilizing agent, and a precipitation of the silver thiocyanate or a complex containing the thiocyanate may be obtained by diluting the treating solution, e.g. by further dipping the article in water or dilute acid, or by spraying the treated article with water, or by treating the article with formaldehyde vapour, or by evaporating the solution upon the article.  Alternatively, the article may be treated with a soluble silver compound, e.g. silver nitrate, in one solution and with a second solution containing ammonium, sodium, potassium or calcium thiocyanate.  A precipitate containing both silver and copper thiocyanates may be obtained by applying a solution containing silver thiocyanate and an alkali metal or ammonium thiocyanate and then treating with a solution containing copper sulphate and sodium metabisulphite at temperatures up to 55 DEG  C., or with copper sulphate and sulphur dioxide simultaneously.  The treatment of absorbent materials may be accompanied by the alternate application of increased and reduced pressure.  In examples: (2) a cheese cloth is impregnated with a solution containing ammonia, 8-hydroxyquinoline, ammonium thiocyanate and silver nitrate with the application of alternating pressure and is subsequently treated with a solution containing copper sulphate and sodium metabisulphite; (5) cotton cloth is padded with an emulsion containing silver thiocyanate and polyvinyl acetate.ALSO:Nylon or rayon fabrics or yarns or rubber articles are impregnated or coated with silver thiocyanate, to impart bactericidal properties to the materials.  A coating may be obtained by precipitating the salt upon the surface of the article treated, or by applying an aqueous emulsion of a binder, e.g. polyvinyl acetate, having the salt dispersed therein, e.g. by precipitation from a solution containing silver thiocyanate and ammonia or another colourless thiocyanate.  The treatment of cellulosic fibres may be accompanied by swelling and penetration of the salt within the fibres.  The articles may be impregnated and/or coated by applying an aqueous solution containing silver thiocyanate and ammonia or sodium, ammonium or calcium thiocyanate as solubilizing agent, and a precipitation of the silver thiocyanate or a complex containing the thiocyanate may be obtained by diluting the treating solution, e.g. by further dipping the article in water or dilute acid, or by spraying the treated article with water, or by treating the article with formaldehyde vapour, or by evaporating the solution upon the article.  Alternatively, the article may be treated with a soluble silver compound, e.g. silver nitrate, in one solution and with a second solution containing ammonium, sodium, potassium or calcium thiocyanate.  A precipitate containing both silver and copper thiocyanates may be obtained by applying a solution containing silver thiocyanate and an alkali metal or ammonium thiocyanate and then treating with a solution containing copper sulphate and sodium metabisulphite at temperatures up to 55 DEG  C., or with copper sulphate and sulphur dioxide simultaneously.  The treatment of absorbent materials may be accompanied by the alternate application of increased and reduced pressure.  In Example (5) cotton cloth is padded with an emulsion containing silver thiocyanate and polyvinyl acetate.ALSO:Cotton, wool, nylon or rayon fabrics, yarns or bolts of cloth; articles such as bedding, clothing, towels, and bandages; paper, leather, rubber or plastic articles are impregnated or coated with silver thiocyanate.  A coating may be obtained by precipitating the salt upon the surface of the article treated, or by applying an aqueous emulsion of a binder, e.g. polyvinyl acetate, having the salt dispersed therein, e.g. by precipitation from a solution containing silver thiocyanate and ammonia or another colourless thiocyanate. The treatment of cellulosic fibres may be accompanied by swelling and penetration of the salt within the fibres.  The articles may be impregnated and/or coated by applying an aqueous solution containing silver thiocyanate and ammonia or sodium, ammonium or calcium thiocyanate as solubilizing agent and a precipitation of the silver thiocyanate or complex containing the thiocyanate obtained by diluting the treating solution, e.g. by further dipping the article in water or dilute acid or by spraying the treated article with water or by treating the article with formaldehyde vapour, or evaporating the solution upon the article.  Alternatively, the article may be treated with a soluble silver compound, e.g. silver nitrate, in one solution and with a second solution containing ammonium, sodium, potassium or calcium thiocyanate.  A precipitate containing both silver and copper thiocyanates may be obtained by applying a solution containing silver thiocyanate and an alkali metal or ammonium thiocyanate and then treating with a solution containing copper sulphate and sodium metabisulphite, at temperatures up to 55 DEG  C., or with copper sulphate and sulphur dioxide simultaneously.  The treatment of absorbent materials may be accompanied by the alternate application of increased and reduced pressure.  In examples: (2) a cheese cloth is impregnated with a solution containing ammonia, 8-hydroxyquinoline, ammonium thiocyanate and silver nitrate with the application of alternating pressure and is subsequently treated with a solution containing copper sulphate and sodium metabisulphite; (5) cotton cloth is padded with an emulsion containing silver thiocyanate and polyvinyl acetate.