PRODUCTION OF VINYL POLYMER

PURPOSE:A specific polymerization initiator is dissolved in a vinyl monomer to effect suspension polymerization in an aqueous medium to produce a vinyl polymer with a wide range of molecular weight distribution which can be used in coating and molding without need for large investment. CONSTITUTION:In the suspension polymerization of a vinyl monomer such as methyl acrylate, styrene, acrylonitrile in an aqueous medium, a polymerization initiator with less than half hour of the half life at the polymerization, usually 90-95 deg.C, e.g., azobisdimethylvaleronitrile in case of 90 deg.C of polymerization temperature or diisopropyl percarbonate at 60-70 deg.C is dissolved in the vinyl monomer, preferably 0.1-20wt% and the mixture is added dropwise to the aqueous medium which is kept at the polymerization temperature, preferably in 0.5-3hr to effect suspension polymerization.