Solid polyurethane powder coating compositions containing uretdione groups that are hardenable at low temperatures

US7572876B2 · kind B2 · utility

Assignee

• EVONIK DEGUSSA GMBH · DE

Inventors

• Emmanouil Spyrou · Schermbeck, DE
• Holger Loesch · Herne, DE
• Andreas Wenning · Nottuln, DE

Key dates

• Filing date: May 3, 2004
• Grant date: Aug 11, 2009
• Expiry date: Jan 26, 2026

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31551
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A highly reactive polyurethane powder coating composition, which contains uretdione groups that are hardenable at low temperatures, contains A) at least one uretdione-containing powder coating hardener based on aliphatic, (cyclo)aliphatic or cycloaliphatic polyisocyanates and hydroxyl-containing compounds, the hardener having a melting point of from 40 to 130° C., a free NCO content of less than 5% by weight, and a uretdione content of 6-18% by weight; B) at least one hydroxyl-containing polymer having a melting point of from 40 to 130° C., and an OH number of between 20 and 200 mg KOH/g; C) 0.001-3% by weight of at least one tetraalkyl ammonium carboxylate catalyst, based on a total amount of components A) and B). Components A) and B) are present in a ratio so that for each hydroxyl group of component B) there is from 0.3 to 1 uretdione group of component A).