New polyisocyanates

Abstract

Abstract Polyurethanes containing reactive isocyanate groups and useful as physiologically inactive polyisocyanates in lacquers and adhesives and in the preparation of high molecular weight products by reaction with polyhydroxy compounds (e.g. polyesters), polyamines or water, are prepared by reacting diisocyanates with trihydric or mixtures of trihydric and dihydric alcohols in proportions such that there are more than one but less than two isocyanate groups per hydroxyl group. The products have more urethane than isocyanate groups and at least one trihydric alcohol residue. The proportion of trihydric alcohol to be used is limited by the production of insoluble products. Specified alcohols are ethylene, diethylene and butylene glycols, hexane diol, methyl hexane diol, glycerol, trimethylol ethane and propane, 1,2,4-trihydroxybutane and triethanolamine. Specified diisocyanates are tetra- and hexamethylene diisocyanates, butane diisocyanate, 4.41-diphenylmethane diisocyanate and toluylene diisocyanate. In examples (1) toluylene diisocyanate and a mixture of 1.3 butylene glycol and trimethylol propane in the OH:NCO ratio of 1:1.22 are reacted at 70 DEG C. in ethyl acetate. The product is useful in lacquers in conjunction with polyesters. (2) Similar to (1) but with an OH:NCO ratio of 1:1.5. The product forms an adduct with phenol at 70 DEG C., the adduct dissociating at a higher temperature. (3) Hexmethylene diisocyanate and a mixture of 1-3 butylene glycol and trimethylolpropane in the OH:NCO ratio of 1:1.66 are reacted at 70 DEG C. in ethyl acetate. The product is useful as an adhesive. (4) Toluylene diisocyanate and a mixture of triethanolamine and 1.3 butylene glycol are reacted in the OH:NCO ratio of 1:1.83 at 50 DEG C. in ethyl acetate. (5) Toluylene diisocyanate and a mixture of trimethylol propane, 1.3 butylene glycol and triethanolamine are reacted in ethyl acetate in the OH:NCO ratio of 1:1.78. The product forms adducts with phenol and malonic ester. (6) Toluylene diisocyanate and trimethylol propane reacted in ethyl acetate at 70-75 DEG C. in the OH:NCO ratio of 1:1.53 to give a low viscosity solution containing 7.8 per cent NCO.ALSO:Polyurethanes containing a plurality of reactive isocyanate groups are prepared by reacting diisocyanates with trihydric alcohols or mixtures of dihydric and trihydric alcohols in proportions such that there are more than one but less than two isocyanate groups per hydroxyl group. The products have more urethane groups than isocyanate groups and at least one trihydric alcohol residue. The proportion of trihydric alcohol is limited by the production of insoluble products. Specified alcohols are ethylene, diethylene and butylene glycols, hexane diol, methyl hexane diol, glycerol, trimethylol propane and ethane, 1,2,4-trihydroxybutane and triethanolamine. Specified diisocyanates are tetra- and hexamethylene diisocyanates, butane diisocyanate, 4,41-diphenylmethane diisocyanate and toluylene diisocyanate. In examples: (1) toluylene diisocyanate and a mixture of 1,3-butylene glycol and trimethylol propane in the OH : NCO ratio of 1 : 1.22 are reacted at 70 DEG C. in ethyl acetate; (2) similar to (1) but with an OH : NCO ratio of 1 : 1.5. The product forms an adduct with phenol at 70 DEG C., the adduct dissociating at a higher temperature; (3) hexamethylene diisocyanate and a mixture of 1.3 butylene glycol and trimethylolpropane in the OH : NCO ratio of 1 : 1.66 are reacted at 70 DEG C. in ethyl acetate. The product is useful as an adhesive; (4) toluylene diisocyanate and a mixture of triethanolamine and 1.3 butylene glycol are reacted in the OH : NCO ratio of 1 : 1.83 at 50 DEG C. in ethyl acetate; (5) toluylene diisocyanate and a mixture of trimethylol propane, 1.3 butylene glycol and triethanolamine are reacted in ethyl acetate in the OH : NCO ratio of 1 : 1.78. The product forms an adduct with phenol and malonic ester; (6) toluylene diisocyanate and trimethylol propane reacted in ethyl acetate at 70-75 DEG C. in the OH : NCO ratio of 1 : 1.53 to give a low viscosity solution containing 7.8 per cent NCO.

Inventors

No inventors recorded.

Bibliographic Details