GB1344725A - Water dispersible coating compositions - Google Patents

Abstract

1344725 Water dispersible curable coating compositions DOW CHEMICAL CO 19 April 1971 [20 April 1970] 26640/71 Headings C3P and C3B A curable coating composition comprises a solution of a vinyl polymer containing pendant carboxylic acid groups, at least half of which are neutralized by ammonia and/or a volatile amine in which the nitrogen atom is not attached directly to an aromatic ring, and a cross-linking agent containing more than one aziridinyl hydroxyalkyl ether or ester group per molecule in a solvent consisting of or containing a watermiscible glycol ether. The composition preferably contains 0À1 to 10 aziridinyl equivalents per carboxyl or carboxylate equivalent, and at least 15% by weight of the glycol ether, based on the cross-linking agent. The polymer may be an interpolymer of monovinyl monomers 1 to 50% by weight of which contain at least one carboxylic acid or carboxylate group. Suitable carboxyl monomers are acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid and the half-esters and half-amides of the dicarboxylic acids. Monomers which may be copolymerized with these include: styrene, vinyl toluene, alphamethyl styrene, halogenated styrenes, t-butyl styrene, esters of acrylic and methacrylic acids, vinyl halides, vinyl acetate, acrylamide, acrylonitrile and methyl vinyl ether, and mixtures thereof. The ammonium or amine salt groups may be introduced by adding the ammonia or amine to a solution of the polymer which contains carboxylic acid groups. The crosslinking agent preferably contains more than one group of the formula where each of R 1 and R 2 is hydrogen or C 1-3 alkyl. In the examples the vinyl polymer is (1), (2), (4) and (6) a copolymer of styrene, methyl methacrylate, butyl acrylate and methacrylic acid which has been reacted with aqueous ammonia; (3) the copolymer of Example (1) which has been reacted with morpholine, triethylamine, dibutylamine, benzylmethylamine, diethyl ethanolamine, N,N- dimethylaminoethylamine, diethanolamine or ethanolamine; (5) a copolymer of (a) styrene, methacrylic acid and 2-ethyl hexyl acrylate, (b) methyl methacrylate, acrylic acid and butylacrylate, (c) vinyl chloride, monobutyl maleate and ethyl acrylate, (d) methyl methacrylate and 2-hydroxyethyl acrylate phthalate half-ester, (e) methyl methacrylate, methacrylic acid and 2-ethylhexyl acrylate and (f) methacrylic acid and butyl methacrylate, each neutralized with ammonia. In Example (6) the coating solution also contains a polyglycidyl ether of bisphenol A. The cross-linking agents may be prepared by reacting a polyepoxide which is a glycidyl ether or ester with an alkyleneimine. In specific examples ethyleneimine is reacted with a diglycidyl ether of bisphenol A or with a diglycidyl ester of tetrahydrophthalic acid.