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AssigneeBayer Aktiengesellschaft
InventorsFrank Richter, Eberhard Stelter, Wilfried Litz, Stefan Groth
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The present invention relates to a process for the preparation of trimerized polyisocyanates that contain at least 30 mole % of iminooxadiazinedione groups (asymmetric trimers) in the trimer mixture, by catalytically trimerizing a starting isocyanate selected from organic di- or 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 formula R.sub.4 P.sup.+ F.sup.- n(HF) wherein R represents identical or different, optionally branched aliphatic, aromatic and/or araliphatic C.sub.1 -C.sub.20 groups, or two or more R groups may also form, with one another and with the phosphorus atom, saturated or unsaturated rings and n has a value of 0.1 to 20.
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 formula
Dependencies are inferred from the claim text.