Process for preparing polyisocyanates containing iminooxadiazinedione groups

US6090939A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Frank Richter · Frankfurt, DE
• Eberhard Stelter · Neunburg vorm Wald, DE
• Wilfried Litz · Neunburg vorm Wald, DE
• Stefan Groth · Leverkusen, DE

Key dates

• Filing date: May 25, 1999
• Grant date: Jul 18, 2000
• Expiry date: May 25, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G18/791
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

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 EQU R.sub.4 P.sup.+ F.sup.- n(HF) wherein PA1 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 PA1 n has a value of 0.1 to 20.