Aminoplast dispersions and polyurethanes prepared therefrom

A process for making a polyurethane resin which comprises reacting an organic polyisocyanate with a stable dispersion having a solids content of about 0.5% to about 80% by weight obtained by condensing ammonia, hydrazine or an organic compound having a molecular weight of from about 50 to about 400 and which contains at least two groups selected from the group consisting of --NH.sub.2 and --NH-- with benzoquinone or a compound of the formula R--Co--R' in which R and R' stand for the same or different radicals selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl groups which may carry chlorine substituents, C.sub.2 -C.sub.4 -alkenyl groups, C.sub.6 -C.sub.10 aryl groups, C.sub.7 -C.sub.10 aralkyl groups, C.sub.5 -C.sub.10 cycloalkyl groups and semi-acetals obtained by reacting said carbonyl compounds with monohydric or dihydric aliphatic alcohols having one to ten carbon atoms in an organic polyhydroxyl compound having a molecular weight of from about 250 to about 14,000 as the reaction medium.