| abstract |
The present invention relates to a process for the production of isocyanurate group-containing polyisocyanates by partially trimerizing the isocyanate groups of (cyclo)aliphatic diisocyanates in the presence of catalysts which accelerate the trimerization of isocyanate groups and optionally in the presence of an inert solvent, terminating the trimerization reaction at the desired degree of trimerization and removing unreacted starting diisocyanate and any other volatile constituents, characterized in that at least one monohydric alcohol containing ester groups corresponding to the formula <IMAGE> is added to the reaction mixture prior to removing the excess starting diisocyanate in a quantity of 1 to 30% by weight, based on the weight of the diisocyanate starting material, and reacted with a portion of the isocyanate groups to form urethane groups, provided that after the trimerization and urethanization reactions, the reaction mixture contains at least 10% by weigth of unreacted starting diisocyanate, based on the weight of the reaction mixture excluding the weight of inert solvent. The present invention also relates to the isocyanurate polyisocyanates obtained by this process and to their use, optionally after blocking with blocking agents for isocyanate groups, for the production of polyurethane plastics and, more particularly, two-component polyurethane coating compositions. |