| abstract |
The invention relates to a one component heat curable powder coating composition system for being cured at a temperature from 60 to 130° C. comprising: a thermal initiation system and a resin system, wherein the reactivity of the thermal initiation system is such that the thermal initiation system provides a geltime between 2.5 and 1000 minutes at 60° C. in butane diol-dimethacrylate as measured according to DIN 16945 using 1 wt % of the thermal initiation system in 99 wt % of butane diol-dimethacrylate, wherein the amount of thermal initiation system is chosen such that when the powder coating composition is applied to a substrate and cured at a temperature of 130° C. for 20 minutes, the coating resists at least 50 acetone double rubs, wherein the resin system comprises a resin and a co-crosslinker, wherein the resin contains reactive unsaturations and wherein said reactive unsaturations are carbon carbon double bonds connected directly to an electron withdrawing group, wherein the co-crosslinker is chosen from methacrylates, vinyl esters, vinyl ethers, vinyl amides, alkyne ethers, alkyne esters, alkyne amides, alkyne amines, propargyl ethers, propargyl ethers, propargyl esters, itaconates, enamines and mixtures thereof, wherein the weight per unsaturation in the resin system is between 100 and 1000 g/mole as determined using 1 H NMR. |