Coating powders for heat-sensitive substrates

A coating powder, the resin system of said coating powder composition comprising:

• A) an epoxy having an epoxy equivalent weight between about 200 and about 1000, and
• B) a carboxylic acid functional polymer having an acid number between about 20 and about 175, the stoichiometric ratio of the epoxy functionality of A) to the carboxylic acid functionality of B) being between about 0.7 and about 1.3, said resin system containing
• C) between about 0.1 and about 2.0 phr of a catalyst of the general formula (I):
• where Z is selected from P, As, and N, the R1s are the same or different and are independently selected from alkyl groups, alkenyl groups, and aryl groups, and the R2s are the same or different and are selected from alkyl groups, phenyl groups, substituted phenyl groups, Br, Cl, I, and F.