Patent GB-531956-A (GB)
Title: Improvements in and relating to synthetic resins and to articles made therefrom
IPC: C08F20/62
Filed: 1939-05-08
Abstract: 531,956. Synthetic resins; esters. NORTON GRINDING WHEEL CO., Ltd. May 8, 1939, No. 13664. Convention date, May 7, 1938.. [Class 2 (iii)] Glass-like, hard, transparent synthetic resin is prepared by polymerizing, by known methods, a mixture comprising wholly or largely monomeric methyl methacrylate and monomeric methacrylic acid. The methacrylic acid preferably amounts to 1-25 per cent. by volume of the monomeric ingredients, the maximum. useful amount being 30 per cent. An additional polymerizable substance or substances may be included in the mixture to modify the refractive index and/or dispersion value, e.g. acrylic or methacrylic acid esters of hydroxyquinolines, nitrophenols, chlorophenols or tripbenylmethyl carbinol ; styrene ; nitroethylene, and o,m, or p-nitrostyrene; reference is also made to a copolymer of vinyl chloride and vinyl acetate. A mixture of 20 per cent. methacrylic acid and 80 per cent. methyl methacrylate, by volume. with or without a catalyst, e.g. benzoyl chloride, held at 45-55‹C. for 1 to 2 days yields a solid, highly transparent product which may be formed into an optical body by casting or moulding, e.g in a polished mould. The product may also be shaped by grinding and polishing. Colour, e.g. for colour filters or protective glasses, may be imparted by employing resins which are naturally coloured or by the use of dyestuffs soluble in the monomer. The optical' properties are approximately proportional to the amount of added substance. Optical bodies made from the polymers may be combined with glass elements, e.g. for correcting chromatic aberration. Spectacle lenses may be secured to nose-pieces and bows of similar compounds. Specification 478,323 is referred to. The Specification as open to inspection under Sect. 91 includes the subject-matter of Specifications 532,022 and 533,497 and also the following matters-(a) copolymers of α-substituted allyl esters of acrylic acid and its homologues, or (b) polyhydric alcohol esters of acrylic acid and its homologues, with (1) derivatives of acrylic acid and α-substituted acrylic acids, (2) vinyl esters, (3) polymerizable substituted ethylenes, (4) mono-vinyl ketones, (5) monovinyl ethers or (6) mono-vinyl aldehydes, the following being specified-(a) α-substituted allyl esters of the formula where X may be hydrogen, methyl, ethyl or other alkyl or aryl groups, or halogen, and R may be alkyl or aryl, e.g. methyl, ethyl, propyl, butyl, alkyl, cyclohexyl, phenyl, tolyl or furyl ; (b) esters of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, pentaglycerol, pentaerythritol, trimethylolpropane and trimethylene glycol ; (1) methyl, ethyl, chlorethyl, isopropyl, ter-butyl, tertiary amyl, phenyl, benzyl, o-cresyl, cyclohexyl and p-cyclohexylphenyl acrylates and methacrylates or cresyl and methacryl amides or chlorides ; (2) vinyl-acetate, mono-, di- and trichloroacetates, propionate or butyrate ; (3) styrene, furyl ethylene, vinyl chloride and nitroethylene; (4) methyl vinyl, phenyl vinyl, isopropenyl methyl, and furyl vinyl ketones; (5) methyl vinyl ether and phenyl vinyl ether; (6) acrolein and α-methyl acrolein. α-substituted allyl esters of acrylic acid and its homologues are prepared by esterifying with the acrylic anhydride, the secondary alcohol obtained by addition of a Grignard reagent to acrolein, esterification being conducted in the presence of a polymerization inhibitor, e.g. pyrogallol or copper methacrylate and in the presence of a base, e.g. pyridine. Specified esters are α - triphenylmethyl-, a - triphenylphenyl- and α - diphenyl allyl methacrylates. This subject-matter does not appear in the Specification as accepted.