Patent GB-865689-A (GB)
Title: Improvements in or relating to synthetic resins
IPC: C08G63/685
Filed: 1958-07-02
Abstract: Copolymerizable unsaturated polyesters are prepared from one or more polyesters having an acid number of 50-350 and having one or more unsaturated and one or more saturated or aromatic components by further esterification with a mixture of mono- and/or polyhydric organic hydroxyl compounds, to form high molecular polyesters with neutral terminal groups, and the product is subjected to heat treatment at a pressure up to 50 mm. Hg.; polymerizable compositions are formed by dissolving the product in a liquid mixture of comonomers.  The polyester is preferably prepared by the following sequence of processes:-(1) the basic structural element is formed from n mols of one or more dicarboxylic acids and at least n+ 1 mols of one or more multivalent alcohols, e.g. glycols, the acids being either wholly aromatic or saturated, e.g. phthalic and/or adipic acid, or wholly insaturated, e.g. maleic and/or fumaric acid, to form a hydroxyl ester; (2) one or more of such esters are then reacted with one or more dibasic acids or anhydrides to convert all the hydroxyl groups to acid ester groups.  Where the hydroxyl ester contains no unsaturation the dibasic acid used should be unsaturated but may be mixed with saturated or aromatic acids; unsaturated hydroxyl esters must be reacted with saturated and/or aromatic acids; (3) the acid polyester is reacted with mixtures of mono- and/or multivalent hydroxyl compounds.  A small amount of an unsaturated dicarboxylic acid may also be added at this stage and preferably part of the hydroxyl compounds is replaced by one or more amines to form amide groups; (4) the product is heated under vacuum to remove low-boiling material.  Some further condensation or deesterification may also occur.  In Examples (1) a saturated hydroxyl ester prepared from glycol, diglycol, phthalic anhydride and adipic acid is reacted with fumaric acid in the presence of hydroquinone and of xylene, as a water entrainer and the acid polyester formed further esterified with glycol, hexane triol, n-hexanol and stearyl amine.  The product is heated for 3 hours at 210 DEG -215 DEG C. and 30-35 torr; (2) an unsaturated hydroxyl ester-formed from glycol, triglycol, fumaric acid and phthalic anhydride is reacted with phthalic anhydride and then with stearyl alcohol, glycol, diglycol, palmityl amine and hexamethylene diamine and volatile matter removed by vacuum distillation; (3) a hydroxyl alkyd-like ester is formed from a monoglyceride (from hexane triol and vicinoleic acid) and phthalic anhydride, reacted with fumaric acid and then with octanol, 1, 3-butanediol, castor oil, stearyl amine and triethanolamine. Copolymers of such polyesters can be made with a mixture of comonomers, the following combinations of comonomers being specified:-(1) styrene, vinyl toluene, ethyl styrene, divinyl benzene and distearyl fumarate; (2) styrene, vinyl toluene, ethyl styrene and divinyl benzene; (3) styrene, vinyl toluene, ethyl styrene, divinyl benzene, dihexyl fumarate; (4) styrene, vinyl toluene, triallyl cyanurate; (5) styrene, vinyl toluene, ethyl styrene, divinyl benzene, dihexyl fumarate, acrylonitrile.  Other unsaturated esters may also be used, particularly coesters of maleic, fumaric or methacrylic acid, e.g. one formed from pentaerythritol, maleic or fumaric acid and butyl or hexyl alcohol or from mannite or pentaerythritol and methacrylic acid.  The compositions are mixed with catalysts, accelerators, inhibitors and driers, preferably as follows:-(a) peroxide catalysts, e.g. benzoyl peroxide, tertiary butyl perbenzoate, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, or cyclohexanone peroxide and benzoyl peroxide; (b) as accelerators heavy metal soaps, e.g. cobalt caprinate in combination with aliphatic or aromatic amines, e.g. diethyl aniline (c) as inhibitors to prevent polymerization merely on standing multivalent phenols or their derivatives, e.g. benzoquinone, hydro quinone or quinhydrone; (d) as drying agents, high molecular weight aliphatic amines, e.g. stearyl or palmityl amine.  The compositions harden on heating to give solids particularly useful as electrical insulators.