SOLUTIONS OF ISOCYANURATE POLYISOCYANATES IN COATINGS SOLVENTS AND A PROCESS FOR THEIR PRODUCTION

The present invention relates to a process for the preparation of a composition containing an isocyanurate polyisocyanate dissolved in a solvent inert to isocyanate groups by a) reacting 2.5 to 7% of the isocyanate groups of a starting diisocyanate based on 2,4-diisocyanatotoluene or a mixture of 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene with a monohydric alcohol corresponding to the formula R1-¢-O-CH2-CH-!n-OH R2 wherein R1 is an aliphatic or cycloaliphatic C6-18 hydrocarbon radical which may be olefinically unsaturated, R2 is hydrogen or a methyl group, and n is 0 or an integer from 1 to 3, b) adding a sufficient amount of an organic solvent which is inert to isocyanate groups to form a 30 to 70% solution of the urethanized diisocyanate either before, during or after step a), c) subsequently partially trimerizing the remaining isocyanate groups of said urethanized diisocyanate in the presence of a catalyst which accelerates the trimerization of isocyanate groups and d) terminating tire trimerization reaction when the content of unreacted diysocyananotoluene is less than 0.5% by weight by the addition of a catalyst poison. The present invention also relates to the solutions of isocyanurate polyisocyanates obtained by this process.