Lacquer polyisocyanates, process for the production thereof and use thereof as isocyanate component in thermosetting two-component polyurethane lacquers

US4369301A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Eberhard Konig · Kronberg, DE
• Josef Pedain · Cologne, DE
• Hans-Joachim Kreuder · Krefeld, DE

Key dates

• Filing date: Oct 16, 1981
• Grant date: Jan 18, 1983
• Expiry date: Oct 16, 2001

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 lacquer polyisocyanates which contain about 0 to 8% free isocyanate groups, about 10 to 28% blocked isocyanate groups and about 2 to 10% of the structural units, --NH--NH--CO--O, all percentages based on the weight of the polyisocyanates, but excluding the weight of the blocking agent. Also provided is a process for preparing these polyisocyanates which comprises reacting about 10 to 30 mol % of the isocyanate groups of an organic polyisocyanate with reaction products which have (i) alcoholic hydroxyl groups and (ii) structural units of the formula, --O--CO--NH--NH--CO--O--, and/or of the formula H.sub.2 N--NH--CO--O--, with the formation of urethane groups and optionally groups corresponding to the formula, --NH--NH--CO--O--, and reacting about 50 to 90 mol % of the isocyanate groups of the organic polyisocyanate with a blocking agent. The reaction products containing alcoholic hydroxyl groups are obtained by reacting 1 mol of hydrazine or of hydrazine hydrate with about 1 to 2 mols of a cyclic carbonate. A final object of the present invention is the use of the new lacquer polyisocyanates as the isocyanate component in thermosetting, two-component…