Liquid polyisocyanate compositions, a process for their preparation, and their use for the preparation of flexible polyurethane foams

摘要

This invention relates to liquid urethane-modified polyisocyanate compositions obtained by reaction of polyisocyanates or polyisocyanate mixtures of the diphenylmethane series containing from about 50 to about 100% by weight diisocyanatodiphenylmethane isomers with substoichiometric quantities of polyether polyol compositions having an average hydroxyl equivalent weight of about 500 to 3000 and an average hydroxyl functionality greater than about 4, optionally followed by mixing the initially formed reaction product with urethane-free polyisocyanates or polyisocyanate mixtures of the diphenylmethane series containing from about 40 to about 100% by weight diisocyanatodiphenylmethane isomers. This invention also relates to a process for the preparation of such polyisocyanate compositions. The invention further relates to the use of such compositions as the polyisocyanate component in the production of flexible polyurethane foams.