Patent ID: 6090939
Filing Date: 2000-07-18
Classification: C07D,C08G

Abstract:
A process for the preparation of a trimerized polyisocyanate that contains at least 30 mole % of iminooxadiazinedione groups (asymmetric trimers) in the trimer mixture which comprises catalytically trimerizing a starting isocyanate comprising a member selected from the group consisting of organic di- and polyisocyanates having a number average molecular weight of 140 to 600 and containing aliphatically, cycloaliphatically and/or araliphatically bound isocyanate groups in the presence of a quaternary phosphonium polyfluoride trimerization catalyst corresponding to the formulaR.sub.4 P.sup.+ F.sup.- n(HF)whereinR represents identical or different, optionally branched aliphatic, aromatic and/or araliphatic C.sub.1 -C.sub.20 groups, or two or more R groups optionally form, with one another and with the phosphorus atom, saturated or unsaturated rings andn has a value of 0.1 to 20.