Patent ID: 7183356

Claim:
A fluororesin powder coating composition comprising a composite fluorinated copolymer (A) having a core/shell structure wherein core particles comprise a fluorinated copolymer (A′), and their surfaces are covered with a resin having a glass transition temperature higher than that of the core particles, constituting shells, wherein the glass transition temperature of the core particles of the composite fluorinated copolymer (A) is from −40 to 50° C., and the glass transition temperature of the resin constituting the shells is from 60 to 150° C., wherein the resin constituting the shells comprises a (meth)acrylate resin, and wherein the composite fluorinated copolymer (A) is a powder obtained by emulsion-polymerizing, in the presence of the fluorinated copolymer (A′) containing a polymerized units based on (a) fluoroolefin and polymerized units based on (b) a vinyl monomer having at least one reactive functional group selected from the group consisting of a carboxyl group, an expoxy group, a hydrolysable silyl group, a hydroxyl group and an amino group, a radical polymerizable monomer mixture comprising (e) a (meth)acrylate having a reactive group which reacts with the reactive group of the above (b), to form a bond, thereby to obtain an aqueous dispersion of a composite fluorinated copolymer (A), and separating and drying the composite fluorinated copolymer (A) from the aqueous dispersion.