Epoxy-urethanes based on copolyesters

Claim 1

An epoxy-urethane consisting essentially of an epoxy endcapped and chain-extended copolyesterurethane, said epoxy-urethane being: I. produced by admixing (a) at least one copolyester, such copolyester produced by the reaction of one linear or more diols or polyether glycols with at least two different dicarboxylic acids, anhydrides of dicarboxylic acids, or methyl esters of dicarboxylic acids, about 40-80 mole percent of said dicarboxylic acids, anhydrides of dicarboxylic acids or methyl esters of dicarboxylic acids being aromatic and about 60-20 mole percent of said dicarboxylic acids, anhydrides of dicarboxylic acids, or methyl esters of dicarboxylic acids being aliphatic, and (b) at least one organic diisocyanate, the molar ratio of isocyanate contained on the diisocyanate to hydroxyl contained on the copolyester being about 0.7/1.0 to about 1/1, at a temperature and for a time sufficient to form a copolyester-urethane; II. reacted to the extent of 10 to 100% of the hydroxyl groups thereof with trimellitic anhydride or a dicarboxylic acid or anhydride thereof selected from the group consisting of malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, brassylic, maleic, fumaric, dilinoleic, diphenic, phthalic, tetrachlorophthalic, isophthalic, terephthalic orthophthalic, cyclohexane dicarboxylic, p-phenylene diacetic, naphthalene dicarboxylic, dihydromuconic, beta-methyl adipic, trimethyl adipic, and ethylether-2,2'-dicarboxylic acids in an amount and for a time to form acid or anhydride endcapped copolyester-urethane with dicarboxylic acid or anhydride; and III. endcapped and/or chain-extended to form said epoxy-urethane by reacting by heat 10-100% of the carboxyl groups of said endcapped copolyester urethane with an epoxy resin of the structure ##STR4## wherein n is an integer sufficient to provide the epoxy resin with an epoxide equivalent of at least about 450 and up to about 6000.