METHOD FOR PRODUCING UREA GROUP AND/OR BURET GROUP-CONTAINING POLYISOCYANATE PREPARATION, POLYISOCYANATE PREPARATION OBTAINED BY SAID METHOD AND USE THEREOF AS ISOCYANATE COMPONENT IN PRODUCTION OF PLASTIC BY ISOCYANATE POLYCONDENSATION

摘要

The present invention is directed to a process for the production of urea- and/or biuret-modified polyisocyanates by reacting organic polyisocyanates with a mixture of high molecular weight isocyanate-reactive compounds and low molecular weight isocyanate-reactive compounds, wherein at least 25% of the isocyanate-reactive groups are primary amino groups. The present invention is further directed to the products obtained by this process and their use for the production of polyisocyanate polyaddition products, especially for the preparation of molded articles by the RIM process.