Process for the production of urethane-modified polyisocyanate compositions using a hydantoin having two hydroxyl alkyl substituents

摘要

Urethane-modified polyisocyanate compositions are made by reacting (a) an organic polyisocyanate or mixture of polyisocyanates having an NCO-content of from 5 to 45 wt % with (b) a hydantoin having an OH number of from 56 to 596 and containing two alcoholic hydroxyl groups. These reactants are used in quantities such that the NCO:OH equivalent ratio is from 2:1 to 50:1. The preferred polyisocyanates are 4,4'-diisocyanatodiphenylmethane and isomer mixtures thereof. The most preferred hydantoin is 5,5-dimethyl hydantoin. These urethane-modified polyisocyanates are particularly useful in the production of polyisocyanate addition products such as polyurethanes and polyisocyanurates.