Thermosetting powders comprising curing agent adducts of polyesters and strong, flexible powder coatings made therefrom

The present invention provides thermosetting polyester powder or epoxy-containing acrylic powder compositions comprising one or more curing agent adduct of a polyester, preferably a linear polyester, wherein when the said curing agent adduct comprises an adduct of one or more polyepoxy compound, the said polyepoxy compound has an average of 2.01 or more epoxy groups per molecule. The compositions provide flexible coatings, films and capstocks having improved impact resistance, especially for use in automotive and architectural applications. To improve impact strength of coatings and films provided thereby, the compositions comprise curing agent adducts of one or more polyepoxy compound chosen from triglycidyl isocyanurate (TGIC) and triglycidyl trimellitate with a carboxyl functional polyester having a carboxyl equivalent weight of 602 or more. In addition, to further improve the impact strength of coatings and films provided thereby, the compositions may comprise one or more adjunct curing agent, such as glycoluril, an aminoplast resin or a blocked isocyanate.