Polyisocyanates blocked with a mixture of blocking agents

US5596064A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Eberhard K onig · Leverkusen, DE
• Theodor Engbert · Recklinghausen, DE

Key dates

• Filing date: Apr 27, 1995
• Grant date: Jan 21, 1997
• Expiry date: Apr 27, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D251/34
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Blocked polyisocyanates containing aliphatically and/or cycloaliphatically bound isocyanate groups blocked by a mixture of blocking agents containing PA1 A) 30 to 70 equivalent % of 1,2,4-triazole, PA1 B) 30 to 70 equivalent % of 3,5-dimethylpyrazole, and PA1 C) 0 to 30 equivalent % of other blocking agents, a method of preparing these blocked polyisocyanates by blocking the isocyanate groups of a (cyclo)aliphatic polyisocyanate, wherein up to 20 NCO equivalent % of the isocyanate groups may optionally be reacted with compounds containing carboxylic acid hydrazide groups and isocyanate-reactive groups, and the use of the blocked polyisocyanates as crosslinking agents for organic polyhydroxyl compounds in one-component polyurethane stoving compositions.