Polyisocyanates blocked with CH-acidic esters and stabilized against thermal yellowing

US6060573A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Eberhard Konig · Kronberg, DE
• Claus Kobusch · Meerbusch, DE
• Wolfram Küttner · Bensberg, DE

Key dates

• Filing date: Mar 17, 1999
• Grant date: May 9, 2000
• Expiry date: Mar 17, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G2150/20
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to a stabilized, aliphatic and/or cycloaliphatic, blocked polyisocyanates which have PA1 i) isocyanate groups blocked with CH-acidic esters, PA1 ii) a content of blocked isocyanate groups (calculated as NCO, MW 42) of 5 to 20, preferably 7 to 15 wt. %, based on the solids content of the blocked polyisocyanate and PA1 iii) a content of formaldehyde of 0.1 to 5 wt. %, based on the solids content of the blocked polyisocyanate. The present invention also related to a process for the preparation of these stabilized, blocked polyisocyanates and to their use in one-component polyurethane stoving compositions, which may be cured at relatively low stoving temperature of about 100.degree. C., as crosslinking agents for organic polyhydroxy compounds.