Blocked polyisocyanates and their use in stoving lacquers

US5691438A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Eberhard Konig · Kronberg, DE
• Theodor Engbert · Recklinghausen, DE

Key dates

• Filing date: Apr 17, 1996
• Grant date: Nov 25, 1997
• Expiry date: Apr 17, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G2115/02
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Polyisocyanates which have 1,2,4,-triazole-blocked isocyanate groups and a blocked isocyanate group content of 7 to 14 wt. % and which are reaction products of PA1 A) a polyisocyanate component selected from (i) lacquer polyisocyanates based on (cyclo)aliphatic diisocyanates or (ii) mixtures of these lacquer polyisocyanates with cycloaliphatic diisocyanates of a maximum molecular weight of 300, PA1 B) 50 to 80 equivalent-%, based on the isocyanate groups of component A), of a monofunctional isocyanate group blocking agent containing at least 90 wt. % of 1,2,4-triazole, PA1 C) 10 to 30 equivalent-%, based on the isocyanate groups of component A), of a polyester component having an OH number of 56 to 250 and PA1 D) 0 to 20 equivalent-%, based on the isocyanate groups of component A), of selected hydrazine derivatives. The present invention is also directed to the use of these blocked polyisocyanates as crosslinking agents in one-component polyurethane stoving lacquers.