Abstract: Novel solvent-based thermosetting composition comprising (a) hydroxy functional epoxy ester resin of number average molecular weight (Mn) between about 1,000 and about 5,000, being formed by reaction of diepoxide, which has been chain extended with diphenol and dicarboxylic acid, with hydroxy functional secondary amine in chain terminating reaction, in approximately 1:1 equivalent ratio: and (b) polyfunctional, hydroxyreactive crosslinking agent, for example, aminoplast crosslinking agent and blocked polyisocyanate crosslinking agent comprising isocyanate groups blocked by reaction with an active hydrogen bearing blocking agent. The coating composition may be formulated as a primer sprayable with conventional spraying equipment.

Abstract: A novel organic solvent based, thermosetting coating composition comprises novel epoxy ester resin having number average molecular weight (M.sub.n) about 1000 to about 5000 and being the reaction product of diepoxide, for example bisphenol-A epichlorohydrin epoxy resin, with (i) diphenol, for example bisphenol-A, in chain extension reaction, (ii) dicarboxylic acid, for example the dimer acid reaction product of the dimerization of C-18 fatty acid, in chain extension reaction, and (iii) fatty acid, for example Soya fatty acid, in chain terminating esterification reaction, which chain extension reactions and esterification reaction occur at least in part substantially simultaneously. Preferably, catalyst is employed for said chain extension and esterification reactions. The coating composition further comprises polyfunctional aminoplast crosslinking agent, for example, hexamethoxymethylmelamine, and polycarboxy functional polymeric catalyst.