Aqueous dispersions of polyhydroxy polyether resins and aminoplast resins

In an aqueous dispersion of a heat curable coating composition made from a mixture of a complex polyhydroxy polyether resin derived from an epihalohydrin and a dihydric phenol and having a melting point of at least 50.degree. C. and an aminoplast or phenolplast resin, the improvement which comprises using as a catalyst for the curing reaction an adduct of phosphoric acid and a glycidyl polyether of a polyhydric phenol reacted in the ratio of about 1 mol of phosphoric acid per each epoxide group of the glycidyl polyether wherein the catalyst is present as an organic base salt of the adducted phosphoric acid and wherein about 0.1 to about 2 weight percent phosphoric acid, in the form of the adduct, is present as the catalyst, said weight percent being based on the total solids content, excluding pigmentation, of the coating composition.