Modified aminoplast crosslinkers and powder coating compositions containing such crosslinkers

摘要

A crosslinking agent which is an ungelled reaction product of (a) at least one aminoplast resin, (b) at least one polyfunctional polymer having functional groups reactive with aminoplast resin (a) and having a glass transition temperature of at least 15° C.; and (c) at least one compound different from (b) having active hydrogen groups reactive with aminoplast resin (a) is provided. Also provided is a method for preparing the crosslinking agent. Further provided is a powder coating composition which includes the crosslinking agent. Additionally provided is a multi-layer composite coating composition having a base coat layer and a top coat over the base coat deposited from the previously described powder coating composition. Coated substrates are also provided.