ISOCYANATE TRIMERS CONTAINING IMINOOXADIAZINE DIONE GROUPS, THEIR PREPARATION AND USE

The present invention relates to a polyisocyanate mixture containing isocyanate trimers provided that i) 30 to 100 mole percent of the trimers are iminooxadiazine diones B and ii) 0 to 70 mole percent of the trimers are isocyanurates A iii) less than 10 mole percent of the polyisocyanate mixture is of the ureto ne imine structural type, and iv) the ratio of the sum of the mole percents of trimers A and B to the mole percent of uretdiones is greater than 4:1 wherein R1 , R2 and R3 are the same or different and represent the groups obtained b y removing an isocyanate group from an aliphatic, cycloaliphatic, aromatic and/or araliphatic isocyanate having an NCO content of less than 70% and/or their oligomers. The present invention also relates to a process for the preparation of the se isocyanate trimers, mixtures of these isocyanate trimers with other polyisocyanates and compositions containing these isocyanate trimers, in which the isocyanat e groups may optionally be blocked with blocking agents, and compounds containing two or more isocyanate-reactive groups. The polyisocyanate mixtures are useful; as starting materials for preparing active ingredients and optionally foamed plastics materials and for the preparation of lacquers, coating compositions, adhesives and additives.