MANUFACTURE OF ISOCYANURATE GROUP-CONTAINING POLYISOCYANATE AND USE THEREOF FOR POLYURETHANE MANUFACTURE

The present invention relates to a process for the preparation of polyisocyanates containing isocyanurate groups by the trimerization of a proportion of the isocyanate groups of organic polyisocyanates and termination of the trimerization reaction by the addition of a catalyst poison, characterized in that the trimerization catalysts employed are quaternary ammonium salts based on the reaction product of tertiary amines and esters of acids of phosphorus which have an alkylating action. The invention also relates to the use of the polyisocyanates with isocyanurate groups obtainable by this process, optionally in a form freed from excess starting polyisocyanates and/or optionally in a form in which the isocyanate groups are blocked with blocking agents, as isocyanate components for the preparation of isocyanate-polyaddition products, especially polyurethanes.