GB419357A - Improvements in or relating to the polymerisation of organic compounds - Google Patents

Abstract

Polymerization products are manufactured by subjecting to polymerizing conditions methacrylonitrile or a mixture containing it, together with a polymer plasticizer of the group comprising acetone, acetoacetic ester, cyclohexanone, benzylidene acetone, dimethyl phthalate, p-tolylsulphonamide, acid anhydrides e.g., acetic anhydride, and bodies containing 5- or 6- membered heterocyclic rings with an oxygen atom as a member of the ring, e.g. coumarin, phthalide, maleic anhydride (which may also undergo polymerization), lactide, and lactones, e.g. butyro- and valerolactones, and also certain of the homologues of these substances, e.g. methyl ethyl ketone, the proportion of methacrylonitrile amounting to not less than 40 per cent and preferably 50-75 per cent of the mixture. The polymerization may be effected with or without the addition of substances promoting polymerization, comprising organic peroxides, e.g. benzoyl or acetyl peroxide, inorganic peroxides, e.g. hydrogen peroxide or ozone, or mixtures of substances capable of forming one of the above, e.g. sodium peroxide and acetic anhydride. The polymer may be obtained in powder form by carrying out the polymerization in emulsion in an aqueous liquid, the emulsion being maintained by addition of an emulsifying or stabilizing agent, e.g. triethanolamine stearate, and by agitation of the mixture. Organic liquids other than plasticizers may be introduced into the emulsion, e.g. solvents for the monomer or the polymer. The latex produced may be coagulated by the addition of a precipitant, e.g., acetone and hydrochloric acid, and the precipitate may be washed free from emulsifying agent and precipitant. The polymerization may be carried out in the presence of a liquid, preferably organic, or mixture of liquids which dissolves the monomeric methacrylonitrile but is a non-solvent for the polymer, which is thus obtained free from bubbles. Suitable liquids are alcohol, petroleum ether, furoic acid, dimethylcyclohexanone, ethyl laevulinate, butyraldehyde, the ethyl ester of acetone dicarboxylic acid, glyoxal, acetylacetone, fenchone, butylene glycol and diacetyl, or mixtures thereof. The liquid employed is preferably also a solvent for the plasticizer. Fillers, dyes, pigments or other modifying agents, e.g. china clay, carbon black, powdered asbestos or wood flour, may be added before, during or after the polymerization. The products may be employed for the manufacture of the shock absorbing layer for safety glass. The material may be cut into sheets, which may subsequently polished, or the material in powder form may be moulded into sheets, e.g., by damping the powder with a suitable solvent or plasticizer, e.g., butyrolactone, acetoacetic ester or fenchone, and applying heat and pressure, e.g., 150lbs. per sq. inch at 110 DEG C. The products may also be moulded into rods, threads or blocks. In examples, methacrylonitrile is heated, usually to 60 DEG C., with benzoyl peroxide with the addition of the following substances: (1) acetoacetic ester; (2) coumarin and a commercial mixture of butyro- and valerolactones; (3) coumarin, butryo- and valerolactones and the substance known under the Registered Trade Mark "Sextone"; (4) lactide and butyro- and valerolactones; (5) butyro- and valerolactones and phthalide; (6) p-tolylsulphonamide and butyro- and valerolactones; (7) butyro- and valerolactones; (8) cyclohexanone; (9) coumarin (in aqueous emulsion with the addition of ammonium and triethanolamine stearates); according to the second Provisional Specification, any of the mixtures of examples (1) to (6) may be polymerized in emulsion; (10) ethyl alcohol and acetone; (11) coumarin, butyro- and valerolactones, acetone and alcohol. Specifications 358,534, 401,653, 416,007, and 417,999 are referred to.