a copolymer in a solid state with a non volatile content of 99 6 a softening point of 105 u00b0 c as measured by the ring and ball softening point method an epoxy equivalent of 500 and a number average molecular weight of 3 100 the copolymer is referred to as polymer a 2 hereinafter components were mixed together at blend ratios shown in tables 1 1 and 1 2 then the mixtures were individually kneaded under heating respectively with a cokneader single screw extruder of model pr 46 manufactured by basf co switzerland after the kneaded mixtures were coarsely ground and pulverized finely powder paints of a mean particle size of 30 to 40 microns u03bcm were prepared table 1 1 blended quantities in examples and comparative examples example example comparative 1 2 example 1 copolymer a 1 83 83 80 a 2 u2014 u2014 u2014 a curing agent dda 1 5 8 20 sebacic acid u2014 u2014 u2014 dega 2 12 9 u2014 mga 3 u2014 u2014 u2014 epga 4 u2014 u2014 u2014 taipaque 25 25 25 cr 93 5 modaflow 6 1 1 1 a powder paint t 1 t 2 t 3 5 trade name of titanium oxide manufactured by ishihara.