Abstract: A process for producing polymer microparticles by suspension polymerization of a vinyl-based monomer in which, when polymer microparticles are produced by suspension polymerization of a vinyl-based monomer, a macromonomer having a radically polymerizable unsaturated group at a terminus of a vinyl-based monomer-derived polymer is used as a dispersion stabilizer.

Abstract: A process for producing high-quality polymer microparticles having uniform particle size of the order of several micrometers to tens of micrometers by inverse suspension polymerization at high productivity while keeping excellent dispersion stability without causing aggregation among particles. The inverse suspension polymerization involves a vinyl monomer and is performed in at least two steps. A water-soluble oxidizing agent and a water-soluble reducing agent are used as a polymerization initiator, and the water-soluble reducing agent is fed after the water-soluble oxidizing agent is fed.

Abstract: The object of the present invention is to provide a process for producing high-quality polymer microparticles having uniform particle size of the order of several micrometers to tens of micrometers by inverse suspension polymerization at high productivity while keeping excellent dispersion stability without causing aggregation among particles. The process is one for the production of polymer microparticles by inverse polymerization of a vinyl monomer and is characterized in that the inverse suspension polymerization is conducted dividing at least two steps, that a water-soluble oxidizing agent and a water-soluble reducing agent are used as a polymerization initiator, and that the oil-soluble oxidizing agent is fed after the water-soluble reducing agent is fed.