Patent GB-1466405-A (GB)
Title: Moulded articles of plastics having surface characteristics and process for producing the same
IPC: C08J7/046
Filed: 1974-11-25
Abstract: 1466405 Coated moulded plastics articles DAINIPPON PRINTING CO Ltd and MISSUBISHI RAYON CO Ltd 25 Nov 1974 [26 Nov 1973 6 Sept 1974] 50937/74 Heading B2E [Also in Divisions C3 and G2] A moulded article of plastics having improved surface characteristics comprises a moulded substrate of plastics and a cured film formed on the surface of the moulded substrate, said film having a thickness of 1-50Á, characterised in that the cured film is formed from a coating material comprising at least 30% by weight of at least one polyfunctional compound selected from polymethacryloyloxy compounds having at least three methacryloyloxy groups in one molecule and a molecular weight of 250-300 and polyacryloyloxy compounds having at least three acryloyloxy groups in one molecule and a molecular weight of 250-300. The coating material may also contain 0.01-5% by weight of a fluorine-containing surfactant, or at least one member selected from monoacryloyloxy, monomethacryloyloxy, diacryloyloxy and diethacryloyloxy compounds. The moulded substrate may be polymethyl methacrylate, copolymers of methyl methacrylate with other vinyl monomers, polystyrene, styreneacrylonitrile copolymers, polyallyl diglycol carbonates. polycarbonates and cellulose esters. The moulded substrate may be less shaped. The polyfunctional compound may be selected from trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, glycerol triacrylate, glycerol tetramethacrylate, di-trimethylolpropane tetraacrylate and ditrimethylolpropane tetramethacrylate. The coating formed on the surface of the moulded plastics substrate may be subjected to heat treatment, in which case the coating material should incorporate 0.01-5% by weight of a polymerisation initiator such as azobisisobutyronitrile, or to irradiation, with light of 2000- 8000A in an atmosphere which does not interfere with the curing, e.g. nitrogen, CO 2 , argon, helium or krypton, in which case the coating material should incorporate a carbonyl compound, or with radiation such as α-rays, #- rays, γ-rays or electron beam. The specific Examples describe the coating of:- polymethylmethacrylate with a monomer composition comprising pentaerythritol tetraacrylate, trimethylolpropane triacrylate and methacrylic acid together with benzoin n-butyl ether and a surfactant selected from polyoxyethylene perfluorocarbonamide, C 5 F 7 H 4 COOC 4 H 9 , potassium perfluorooctasulphonate, and a mixture of polyoxyethylene perfluorocarbonamide and polyethylene glycol oleyl ether (1); polymethylmethacrylate with a monomer composition comprising pentaerythritol tetraacrylate, trimethylolpropane triacrylate and ethylene glycol dimethacrylate together with benzoin nbutyl ether (4) and a surfactant selected from polyoxyethylene perfluorocarbonsulphonamide, polyoxyethylene perfluorocarbonamide, HC 6  F 12 CH 2 OCH 3 , perfluorocarbon sulphonamide propyldimethylamine hydrogen chloride, N- potassium carboxymethyl perfluorocarbon sulphonamide, and potassium perfluorocarbon sulphate (2) (5) (8) polyallyl diglycol carbonate backed with a layer of quartz with a monomer composition of trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1, 3- butylene - glycol dimethacrylate together with benzoin isopropyl ether and optionally polyoxymethylene perfluorocarbonamide (3); a polycarbonate. with a monomer composition comprising pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate and methyl methacrylate together with benzoin n-propyl ether (6); and a polymethyl methacrylate with a monomer composition comprising pentaerythritol tetraacrylate, trimethylolpropane triacrylate and propylene glycol diacrylate together with benzoin isopropyl ether and a fluorine containing non- ionic surfactant. The coated substrate in the specific Examples are subsequently irradiated with light of 3650 in a nitrogen atmosphere (1, 2, 3, 5); a mercury lamp in CO 2  (4); a mercury lamp in N 2  (6, 8, 9); and a carbon arc in helium. The coating material may be applied by spray-, brush-, flow-, dip-, rotary- or roll-coating.