Condensation products of dialdehydes and nitrogenous compounds

Resins useful as surface coatings are prepared by reacting dialdehydes having at least 5 carbon atoms with a dihydrazide, e.g. sebacic or adipic dihydrazide, a diamide of a dicarboxylic acid or urea. The condensation is preferably effected in the absence of a catalyst. A solvent, e.g. an alcohol or ether, may be employed. Equimolecular proportions of the reactants are preferably employed. Specified dialdehydes are cyclohexane dialdehydes, succindialdehyde, glutardialdehyde, 2-methoxymethyl- and 2-ethoxymethyl-2 : 4-dimethylpentane-1 : 5 dials. In examples: (1) equimolar proportions of 2-methoxymethyl-2 : 4-dimethyl-pentane-1 : 5 dial and sebacic dihydrazide were reacted at 50-170 DEG C. in an atmosphere of nitrogen to give a viscous resin which on cooling became a clear yellow glass; (2) 69 parts urea and 172 parts 2-methoxymethyl-2 : 4-dimethylpentane-1 : 5 dial were reacted at about 110 DEG C. in an atmosphere of nitrogen to give a clear, hard, brittle resin. In both examples water was evolved. Specification 706,176 is referred to. The Provisional Specification describes the reaction of dialdehydes with polyamines, in particular of 2-methoxymethyl - 2,4 - dimethylpentane - 1,5 dial with hexamethylene diamine and p-phenylene diamine.