GB936056A - Improved articles of polycarbonates - Google Patents

Abstract

Shaped articles of high molecular weight polycarbonates having improved scratch resistance are produced by treating the article with a solution comprising an aminoplast in an organic solvent and thereafter drying the treated article. The term "aminoplast" is defined as the resinous product formed by the interaction of an aldehyde, e.g. formaldehyde, and a compound containing more than one amino group per molecule, e.g. urea, melamine, triazine and derivatives thereof, a triazine substituted by amino groups, thiourea and guanidine, or mixtures thereof. The aminoplast may be modified with the condensation product of an aliphatic polyhydric alcohol, e.g. glycols, glycerols, and an aliphatic polycarboxylic acid. The aminoplast may be in admixture with an epoxy resin based on diphenylolpropane and epichlorhydrin which may have a molecular weight between 1500 and 4000, an epoxy value of 1,1 to 1,6, and a hydroxyl value of 0,33 to 0,41, and may be present in the ratio by weight, aminoplast: epoxy resin of 9:1 to 1:9. The aminoplast may be dissolved in organic solvents such as acetone, methyl ethyl ketone, trichloroethylene, toluene, xylene, methanol or butanol, or mixtures thereof. The aminoplast solution may contain a polydimethyl siloxane oil in a concentration of 10-5 to 10-1% of the weight of solid substance. The solution may also contain plasticizers, e.g. triphenyl phosphite or a chlorinated diphenyl having a chlorine content of 50 to 70%; acid catalysts, e.g. phosphoric or p-toluene sulphonic acids, benzene sulphochloride or p-toluenesulphochloride; varnish raw materials, e.g. alkyd resins, vinyl polymers such as polyvinyl acetate, polyvinyl acetal or vinyl acetate-vinyl chloride copolymers, and epoxy modified polycarbonates and may be applied by dipping or spraying, or by means of spreader rolls. The polycarbonate may be prepared by reacting aromatic bishydroxy compounds, examples of which are given, with phosgene, or bis-chloroformic acid esters or diesters of carbonic acid. The coated polycarbonate foil may be a light transmitting foil and may be coated with antihalation layers e.g. containing an antihalation dye in a solution of a copolymer of vinyl butyl ether, acrylonitrile and maleic acid monoethyl ester, or light sensitive photographic layers, e.g. containing diazonium salts or silver halide in a gelatin emulsion. Specifications 790,023, 808,629, 813,000, 853,088, 853,587 and 887,543 are referred to.ALSO:A composition for coating foils and other shaped articles of high molecular weight polycarbonates comprises a solution in an organic solvent of an aminoplast formed by the interaction of an aldehyde, e.g. formaldehyde, and a compound containing more than one amino group per molecule, e.g. urea, melamine, triazine and derivatives thereof, a triazine substituted by amino groups, thiourea and guanidine, or mixtures thereof. The aminoplast may be modified with the condensation product of an aliphatic polyhydric alcohol, e.g. glycols, glycerols, and an aliphatic polycarboxylic acid. The aminoplast may be in admixture with an epoxy resin based on diphenylolpropane and epichlorhydrin which may have a molecular weight between 1,500 and 4,000, an epoxy value of 1,1 to 1,6, and a hydroxyl value of 0,33 to 0 1, and may be present in the ratio by weight, aminoplast: epoxy resin of 9:1 to 1:9. The aminoplast may be dissolved in organic solvents such as acetone, methyl ethyl ketone, trichloroethylene, toluene, xylene, methanol or butanol, or mixtures thereof. The aminoplast solution may contain a polydimethyl siloxane oil in a concentration of 10-5 to 10-1% of the weight of solid substance. The solution may also contain plasticizers, e.g. triphenyl phosphite or a chlorinated diphenyl having a chlorine content of 50 to 70%; acid catalysts, e.g. phosphoric or p-toluene sulphonic acids, benzene sulphochloride or p,toluenesulphochloride; varnish raw materials, e.g. alkyd resins, vinyl polymers such as polyvinyl acetate, polyvinyl acetal or vinyl acetate-vinyl chloride copolymers, and epoxy modified polycarbonates and may be applied by dipping or spraying, or by means of spreader rolls. The polycarbonate may be prepared by reacting aromatic bis-hydroxy compounds, examples of which are given, with phosgene, or bis-chloroformic acid esters or diesters of carbonic acid. The coated polycarbonate foil may be a light transmitting foil and may be coated with antihalation layers, e.g. containing an antihalation dye in a solution of a copolymer of vinyl butyl ether, acrylonitrile and maleic acid monoethyl ester, or light sensitive photographic layers, e.g. containing diazonium salts or silver halide in a gelatin emulsion. Specifications 790,023, 808,629, 813,000, 853,088, 853,587 and 887,543 are referred to.