摘要 |
<p>Polyisocyanato-polyisocyanurates are prepared by catalytically cyclotrimerizing a polyisocyanate in the presence of a catalytically effective amount of an aminosilyl catalyst, and which is characterizing by terminating the cyclotrimerization reaction when a predetermined desired amount of isocyanurate groups has been obtained, by adding to the reaction mixture a reaction terminating amount of an organic catalyst deactivating compound comprising at least one free hydroxyl moiety, or the reaction product of such hydroxylated organic catalyst deactivating compound with an isocyanate.</p> |