PURPOSE: To effect suspension polymerization stably and prevent the formation of fine suspended particles floating in the waste poymerization water, by bulk- suspension-polymerizing an aromatic vinyl monomer in the presence of a rubber- like polymer with the aid of a cellulose derivative, PVA and a phosphate.
CONSTITUTION: In a polymerization process comprising bulk-polymerizing an aromatic vinyl monomer or an aromatic vinyl monomer and a vinyl cyanide monomer, thereby obtaining a polymer solution having a viscosity at 65°C of above 40P, transferring the bulk-polymerized polymer solution into a suspension polymerization system containing water as a medium, and continuing the suspension polymerization; use is made of (a) 0.01W0.5pt.wt. hydroxypropylmethylcellulose, (b) 0.001W0.04pt.wt. partially saponified polyvinyl alcohol and (c) 1W100 times as much (based on the sum of a and b) difficultly water-soluble phosphate.
OOTSUKA ICHIROU
IIO KEIJI
AIHARA HISASHI
INOUE HARUO
