Polycarboxylic acid/ester-diamine aqueous coating composition

Claim 1

Aqueous coating solution comprising by weight (A) from about 40% to 75% of solids and (B) from about 25% to 60% of solvent, where (A) is a polycarboxylic acid/ester-organic diamine mixture wherein the organic diamine has the formula, NH.sub.2 R.sup.1 NH.sub.2, is present in about equal molar amounts and up to about a 25 mole percent excess over the moles of organic polycarboxylic acid/ester which mixture is a member selected from (i) a mixture of 40 to 80 mole percent of tetra-acid of the formula, ##STR9## and 20 to 60 mole percent of a half-ester of the formula, ##STR10## or (ii) a mixture consisting essentially of (i) and from 0 to 10 mole percent, based on total moles of said tetra-acid and said half-ester, of organic dianhydride of the formula, ##STR11## where (B) is a solvent mixture comprising by weight 1 to 20% by weight of water and 80 to 99% by weight of monoalkyl glycol ether having 1 to 4 carbon atoms in the alkyl group, where R is a C.sub.(6-30) aromatic organic radical, R 1 is a C.sub.(6-30) organic radical, R 2 is an alkyl terminated alkylene ether or dialkylene ether radical and R 3 is selected from R 2 or hydrogen.