Abstract: The invention relates to a resin composition comprising at least an organophosphorous compound and a branched amorphous carboxylic acid functional polyester, said polyester having a Tg of at least 40° C., said polyester comprising at least 1 to 45% mol of 2,2-dimethyl-1,3-propanediol; a C3 to C5 aliphatic diol AD1 not including 2,2-dimethyl-1,3-propanediol; a C6 to C50 aliphatic or cycloaliphatic diol AD2; 0.1 to 10% mol of an at least trifunctional monomer; 1 to 55% mol of terephthalic acid, wherein the % mol is based on the polyester. The powder coatings of the present invention derived upon curing at low temperature of the thermosetting powder coating compositions of the invention that were storage stable and comprised said resin composition and a crosslinker having functional groups that are reactive with the carboxylic acid groups of the polyester, have limited or no blooming, good smoothness sufficient reverse impact resistance and preferably have also good degassing limit.

Abstract: The invention relates to a resin composition comprising at least an organophosphorous compound and a branched amorphous carboxylic acid functional polyester, said polyester having a Tg of at least 40° C., said polyester comprising at least 1 to 45% mol of 2,2-dimethyl-1,3-propanediol; a C3 to C5 aliphatic diol AD1 not including 2,2-dimethyl-1,3-propanediol; a C6 to C50 aliphatic or cycloaliphatic diol AD2; 0.1 to 10% mol of an at least trifunctional monomer; 1 to 55% mol of terephthalic acid, wherein the % mol is based on the polyester. The powder coatings of the present invention derived upon curing at low temperature of the thermosetting powder coating compositions of the invention that were storage stable and comprised said resin composition and a crosslinker having functional groups that are reactive with the carboxylic acid groups of the polyester, have limited or no blooming, good smoothness sufficient reverse impact resistance and preferably have also good degassing limit.