Process for polyaddition products which contain uretdione groups and use in coatings

US4044171A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hanns P. Muller · Leverkusen, DE
• Kuno Wagner · Leverkusen, DE
• Richard A. Muller · Berkeley, US

Key dates

• Filing date: Apr 17, 1975
• Grant date: Aug 23, 1977
• Expiry date: Apr 17, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G2250/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention teaches a novel polyisocyanate lacquer binder and a method preparing it. The binder is prepared by reacing uretidione containing polyisocyanates optionally mixed with uretdione free diisocyanates with water or with low molecular weight compounds which have two alcoholic hyroxyl groups per molecule. Optionally these compounds may be mixed with up to 60 wt.% based on the total weight of hydroxyl bearing compounds, of low molecular weight compounds with one active alcoholic hydroxyl group per molecule. The proportion of reactants is so selected that the binder produces has from 5 to 20 wt.% of latent isocyanate groups in the form of unopened uretdione rings. The binder can then be mixed with polyhydroxyl compounds having molecular weights of 400 to 10,000 and conventional lacquer pigments and fillers. This mixture can then be coated on a substrate and the coating heated to above 110.degree. C to effect hardening.