DE1570590

Polyurethanes prepared by reacting polyhydroxyl compounds with polyisocyanates and which contain incorporated in the molecule two or more groups of the formula in which the phosphorus atom is linked to a carbon atom directly or through an oxygen or nitrogen atom are cross-linked by reacting them at - 20 DEG to 250 DEG C. with a compound which may be resinous and which contains at least two azomethine groups in the molecule. The polyurethanes are suitably prepared by reacting an organic polyisocyanate with a polyhydroxyl containing compound having a M.W. greater than 1000 and/or a polyhydroxyl compound having a M.W. less than 1000 either or both of the polyhydroxyl containing compounds containing at least one of the above specified phosphorus containing groups. Suitable polyhydroxyl containing compounds having a M.W. greater than 1000 and containing the above specified phosphorus containing groups are condensation products of lower dialkylphosphites or diphenylphosphite with polyesteramides, polyacetals, polyesters, polyethers, polythioethers or low M.W. polyhydroxyl containing compounds. The corresponding compounds having a M.W. less than 1000 may be prepared by reacting lower dialkylphosphites and low M.W. polyhydroxyl containing compounds, by reacting phosphorous acid and alkylene oxides and by reacting esters, amides or chlorides of trivalent phosphorus with aminoalcohols or polyamines. Conventional polymeric and monomeric polyhydroxyl-containing compounds may also be included in the reaction system. The one-shot or prepolymer techniques may be employed to form the polyurethanes, using conventional polyisocyanates. Suitable compounds containing at least two azomethine groups are reaction products of monoaldehydes or ketones with polyamines or of polyaldehydes with primary alkyl- and hydroxyalkyl amines. The azomethine group containing compounds may be prepared in the cross-linking reaction mixture, and the reaction may be carried out in the presence of a solvent. Polyesters may be prepared by reacting di-(b -chloroethyl)-phosphite with (a) 1,6-hexane diol, (b) diphenylolpropane - di - (b - hydroxyethyl-ether) or (c) N,N-di-(b -hydroxyethyl)-aminomethyl-phosphonic acid diethyl ester.ALSO:Glass and copper plates may be coated with a composition comprising (i) a polyurethane which has been prepared from polyhydroxyl compounds and polyisocyanates and which contains in the molecule two or more groups of the formula: