PROCESS FOR THE PRODUCTION OF POLYISOCYANATE PREPARATIONS CONTAINING UREA AND/OR BIURET GROUPS THE POLYISOCYANATE PREPARATIONS OBTAINABLE BY THIS PROCESS AND THEIR USE AS ISOCYANATE COMPONENT IN THE PRODUCTION OF PLASTICS BY THE ISOCYANATE-POLYADDITION

摘要

A PROCESS FOR THE PRODUCTION OF POLYISOCYANATE PREPA RATIONS CONTAINING UREA AND/OR BIURET GROUPS, THE POLY ISOCYANATE PREPARATIONS OBTAINABLE BY THIS PROCESS AND THEIR USE AS ISOCYANATE COMPONENT IN THE PRODUCTION OF PLASTICS BY THE ISOCYANATE-POLYADDITION PROCESS 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 isocyanatereactive compounds and low molecular weight isocyanatereactive 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.