Process for the preparation of polyisocyanates containing isocyanurate groups and their use in the production of polyurethanes

Abstract

The subject of the invention is a process for the preparation of polyisocyanates containing isocyanurate groups which comprises trimerizing a proportion of the isocyanate groups of organic polyisocyanates or mixtures of di- and monoisocyanates in the presence of basic alkali metal compounds as catalysts and terminating the trimerization reaction by the addition of a catalyst poison, characterized in that the trimerization catalysts are complexes of (i) basic alkalimetal compounds and (ii) acyclic organic compounds which (a) have at least 6 alkylene oxide units of the formula --R--O--, wherein R represents C.sub.1 -C.sub.4 -alkylene, in the form of one or more polyether chains with only those chains having at least three alkylene oxide units being counted to achieve the total of at least 6 alkylene oxide units (b) contain a total of at least about 40% by weight of alkylene oxide units, the alkylene oxide units of any chains containing less than three of these units not being counted as alkylene oxide units, and (c) have a molecular weight of at least about 282. The invention also relates to the use of the process products according to the invention, optionally freed from excess starting polyisocyanates and/or optionally blocked with blocking agents for isocyanate groups, as an isocyanate component for the production of polyurethanes by the isocyanate polyaddition process.

Dependencies are inferred from the claim text.