Aminoplast-based crosslinkers and powder coating compositions containing such crosslinkers

Abstract

Provided is a crosslinking agent which is the ungelled reaction product of a polyester polyol and an aminotriazine compound having one or less non-alkylated NH bond per triazine ring. The polyester polyol is the reaction product of a cycloaliphatic polyol and a cyclic polycarboxylic acid or anhydride. The crosslinking agent is essentially free of hydroxyl functionality and has a glass transition temperature of at least 10° C. Further provided is a powder coating composition including a solid particulate film-forming mixture of a polymer containing reactive functional groups and having a Tg of at least 30° C., and the crosslinking agent. Additionally provided is a multi-layer composite coating composition having a basecoat layer deposited from a basecoat film-forming composition and a topcoat over the basecoat deposited from the previously described powder coating composition. Coated substrates are also provided.

Dependencies are inferred from the claim text.