Patent GB-948491-A (GB)
Title: Improvements in thermoset compositions based on carboxy polymers and epoxide resins
IPC: C09D157/00
Filed: 1960-04-29
Abstract: Heat-convertible solvent-thinned resinous compositions comprise (a) a nitrogen-free polyepoxide and (b) a carboxy copolymer which comprises an alpha-beta monounsaturated monocarboxylic acid containing up to four carbon atoms and a monoethylenically unsaturated monomer free of carboxyl groups which is copolymerised therewith, the carboxy copolmer comprising more than 15% but not more than 30% of the acid based on the total weight of the carboxy copolymer and the composition comprising 0.7 to 2 equivalents of polyepoxide per equivalent of carboxy copolymer. The epoxy resin may be a glycidyl polyether of a polyhydric alcohol or phenol, e.g. bisphenol A, or an epoxy ester, e.g. 3,4-epoxy-6-methylcyclohexyl-methyl 3,4-epoxy-6-methylcyclohexylcarboxylate and bis(3,4 - epoxy - 6 - methylcyclohexyl-methyl) suberate, or it may be the diglycidyl ether of trimethylolpropane, dicyclopentadiene diepoxide, the bisepoxydicyclopentyl ether of ethylene glycol or an epoxydised drying oil, e.g. epoxidised soya oil. The carboxy copolymer may be derived from acrylic methacrylic or crotonic acid copolymerized with other monomers or mixtures of monomers which may be styrene, halostyrenes, cyanostyrene, dialkylstyrenes, isopropenyl-toluene, vinylnophthalene, a -methylstyrene, acrylic, methacrylic and crotinic esters of saturated alcohols, acrylonitrile, methacrylonitrile or unsaturated alcohol esters of saturated monocarboxylic acids. Many such monomers are specified. The solvent may be mixtures of two or more of xylene, 2-ethoxyethyl acetate, methyl isobutyl ketone and diacetaone alcohol. The compositions may be cured by heating with or without a catalyst which may be amines amine salts or quaternary ammonium salts or hydroxides many of which are specified.  In comparative examples copolymers comprising 15% or less by weight of the unsaturated acid are used.  In examples the following copolymers (in which parts are by weight) are prepared by solution polymerisation using, as catalyst, benzoyl peroxide or di-t-butyl peroxide:-65/20/15 styrene/methyl acrylate/acrylic acid; 65/20/15 vinyltoluene/methylacrylate/acrylic acid; 60/20/20 vinyltoluene/methylacrylate/acrylic acid; 60/20/20 styrene/methylacrylate/acrylic acid; 72/20/8 vinyltoluene/methylacrylate/acrylic acid; 68/20/12 vinyltoluene/methylacrylate/acrylic acid and 40/35/25 vinyltoluene/methylacrylate/methacrylic acid.  Specifications 730,869 and 948,493 are referred to.ALSO:Coating compositions which are heat-convertible and solvent-thinned resinous compositions comprising (a) a nitrogen-free polyepoxide and (b) a carboxycopolymer which comprises an alpha-beta monounsaturated monocarboxylic acid containing up to four carbon atoms and a monoethylenically unsaturated monomer free of carboxyl groups, the copolymer containing more than 15% but not more than 30% by weight of the acid and the composition comprising 0,7-2 equivalents of polyepoxide per equivalent of carboxy copolymer and containing optionally a curing catalyst are drawn down in films on glass plates.  The copolymer may be made from acrylates, styrene, and/or vinyl esters.  The coatings are cured by heating.