Low-temperature-curable, solid polyurethane powder coating compositions containing uretdione groups

US6914115B2 · kind B2 · utility

Assignee

• Degussa AG · DE

Inventors

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

Key dates

• Filing date: Nov 27, 2002
• Grant date: Jul 5, 2005
• Expiry date: May 1, 2023

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31605
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Polyurethane powder coating compositions containing uretdione groups and curing at low temperatures are provided, along with processes for preparing such compositions, and their use as powder coatings, wherein the compositions generally contain: A) a uretdione-containing powder coating hardener derived from aliphatic, (cyclo)aliphatic, cycloaliphatic or aromatic polyisocyanates and hydroxyl-containing compounds, and having a melting point 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) a hydroxyl-containing polymer having a melting point from 40 to 130° C., and an OH number between 20 and 200 mg KOH/gram, and C) a catalyst of the formula [NR1R2R3R4]+[R5]−, in which R1-R4 simultaneously, or independently of one another, are alkyl, aryl, aralkyl, heteroaryl or alkoxyalkyl radicals, and each R1-R4 is aromatic, linear or branched, unbridged or bridged with other radicals, R1-R4.