| abstract |
The invention relates to a process for the preparation of trimerizate polyisocyanates with at least 30 mol% of iminooxadiazinedione groups (asymmetric trimers) in the trimers mixture by catalytically induced trimerization of organic di- or polyisocyanates, characterized in that quaternary phosphonium fluorides of the general formula R 4 P + are used as the trimerization catalyst F - ยท n (HF), where R stands for identical or different, optionally branched, aliphatic, aromatic and / or araliphatic C 1 -C 20 radicals and optionally forms two or more substituents R with one another and with the phosphorus atom also saturated or unsaturated cycles can be used and n can have any value between 0.1 and 20. |