US Patent 7589159 Process for producing radical polymer

The present invention provides a process for producing a resin powder containing a radical polymer having a volume-average primary-particle diameter of 1 nm to 300 nm and containing no impurities such as surfactants by a simple procedure without via multistage reactions. The process for producing a resin powder (J) comprising a radical polymer obtained by polymerizing a bifunctional radical-polymerizable monomer (A) with a ter- or higher functional radical-polymerizable monomer (B) in the presence of 15 mol % to 170 mol % polymerization initiator (C), based on the sum of monomers (A) and (B).