PROCESS FOR THE PREPARATION OF POLYMETHYLENE POLYPHENY POLYISOCYANATE COMPOSITIONS AND USE THEREOF

摘要

A polymethylene polyphenyl polyisocyanate composition comprising polymethylene polyphenyl polyisocyanates, a part of the isocyanate groups contained therein being substituted by a carbamate group, or said polymethylene polyphenyl polyisocyanates having the substituted carbamate group and polymethylene polyphenyl polyisocyanate not having carbamate group, the total amount of the isocyanate groups contained in the composition being up to 10% by mole based on the total amount of isocyanate groups contained in the composition. The composition is useful for the preparation of rigid polyurethane which has many industrial applications. A process for the preparation of the composition is also disclosed.