GB1406419A - Metal phosphate coating or organic polymers - Google Patents

Abstract

1406419 Metal phosphates IMPERIAL CHEMICAL INDUSTRIES Ltd 11 Sept 1972 [20 July 1971 29 Oct 1971 4 Nov 1971 26 Nov 1971 (2) 20 Dec 1971 2 June 1972] 47614/74 47615/74 47616/74 47617/74 47618/74 47619/74 and 47620/74 Divided out of 1406233 Heading C1A [Also in Division B2] Organic polymer substrate has a coating comprising at least one metal phosphate, the metal having an atomic number of 12, 14, 20-32, 39-50, 56-80, 90 or 92, the phosphate being derived from an oxyacid of phosphorus having the structure where X<SP>1</SP> and X<SP>2</SP> are the same or different and are selected from hydrogen, hydroxide and halide and in which X<SP>2</SP> may have the structure Phosphates of Fe, Ti, Cr and V are specifically mentioned to provide pyrophosphate. The coating may be produced by applying to the organic polymer substrate a coating composition comprising a solution of the compound of the metal and an oxyacid of phosphorus or a compound capable of forming such an oxyacid in a solvent which comprises at least in part an organic component and heating the coating to produce the metal phosphate. The organic solvent is preferably an alcohol, ester, ketone, aldehyde, nitro-compound or ether especially monohydric alcohols ROH and esters of the structure R<SP>1</SP>COOR<SP>2</SP> where R, R<SP>1</SP> and R<SP>2</SP> are alkyl groups or substituted alkyl groups containing 1-10 carbon atoms, ethers of the structure R<SP>1</SP>OR<SP>2</SP> and ketones of the structure R<SP>1</SP>COR<SP>2</SP>, nitro-compounds of the structure R<SP>1</SP>NO 2 and cyclic ethers of the structure OR<SP>3</SP> where R<SP>3</SP> is a divalent alkyl group having 4-7 carbon atoms one of which may be replaced by an oxygen atom. Numerous suitable specific compounds are listed. Two or more solvents may be used and diluents may be present such as aromatic or halogenated hydrocarbons. The composition may be formed by dissolving a metal compound and an oxyacid of phosphorus, or a source thereof, such as the anhydride or oxyhalide, in a solvent for at least one component and for the reaction product in the presence of an organic diluent. The metal compound may be phosphate and so provide the oxyacid of phosphorus in which case an additional acid may be required. Suitable metal compounds are oxides, hydroxides, halides, carbonates, nitrates, perchlorates and cyanates. Salts of organic acids such as acetates, benzoates, oxalates, propionates or formates may also be used as well as alkoxides and co-ordination complexes such as those having ligands derived from acetyl acetone, ethylene dithiol, ethanolamine, carbon monoxide or phosphines. Other components such as pigments, polymers, colorants, surfactants or sources of other ions and other additives may be included. Suitable polymers are diene polymers, acetylene polymers, vinyl and vinylidene polymers, such as acrylic acid and methacrylic acid polymers, acrylic and methacrylic polymers, polyacrylonitrile, polyethers, polysulphones, formaldehyde resins, polyesters, polycarbonates, polyamides, polyureas and polyurethanes, natural polymers and modified natural polymers and polysiloxanes. The organic polymer substrate may be in the form of a fibre, filament, sheet, film, granule or powder and may be applied by dipping, spraying, roller or brush. The coating may be up to 10 microns thick but what is preferably 0À01 to 5 microns thick. Thicker coatings may be obtained by repeated application of the compositions. The substrates to which the compositions may be applied include cellulosic polymers such as wood and paper and synthetic polymers such a polyolefines, e.g. polymers and copolymers of ethylene, propylene, butadiene, isoprene, 4-methylpentene-1 and styrene, copolymers of ethylene with unsaturated esters such as vinyl acetate or alkyl acrylates, methacrylates, modified styrene copolymers such as styrene-maleic anhydride and styrene-acrylonitrile copolymers, polymers and copolymers of other ethylenically unsaturated monomers such as vinyl chloride, vinylidene chloride, chloroprene, methyl methacrylate, ethyl acrylate, vinyl acetate, polyphenylene oxides and sulphides, polysulphones, polyoxymethylenes, polyamides, such as nylon 6, nylon 6-6 and nylon 11, polycarbonates and polyesters such as polyethylene 1,2-diphenoxyethane - 4,4<SP>1 </SP>- dicarboxylate and polyethylene terephthalate. The phosphate coatings may form a primer or outer coating for the surface of the polymer material which should be painted, printed or metallized or further coated with one or more phosphate coatings.