Patent ID: 6107484
Filing Date: 2000-08-22
Classification: C07D,C08G

Abstract:
A process for the production of a trimerized polyisocyanate containing at least 30 mole % of iminooxadiazinedione groups (asymmetric trimers) in the trimer mixture which comprises 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 ammonium or phosphonium fluoride trimerization catalyst corresponding to the formulaR.sub.4 E.sup.+ F.sup.- (I),whereinE represents N or P andR represents identical or different, optionally branched, aliphatic, aromatic and/or araliphatic C.sub.1 -C.sub.20 groups, or two or more R groups form, with one another and with the nitrogen or phosphorus atom, saturated or unsaturated rings,in which the catalyst isi) present in unsolvated form, orii) blended with a solvating agent S for the fluoride anion, wherein S comprises a member selected from the group consisting of protic compounds having a pK.sub.a value of greater than 2 (determined in H.sub.2 O at 25.degree. C.) or oxalic acid, provided that the molar ratio of solvating agent S to fluoride ion, F.sup.-, does not exceed 20, and provided that S is not HF or an alcohol having a functionality of 2 or more, oriii) blended with water, wherein the molar ratio of water to fluoride ions (F.sup.-) does not exceed 10.