| abstract |
The production process includes starting suspension polymerization of vinyl chloride-based monomer in a polymerization vessel in the presence of a particular combination of suspending agents; and, at the time when a polymerization conversion has reached 5 to 60%, further adding to the reaction mixture a partially saponified polyvinyl alcohol having an average polymerization degree of 1,500 to 4,000 and a saponification degree of 75 to 98 mole %, wherein a carboxylic acid ester of polyhydric alcohol is further added to at least one one selected from a content inside the polymerization vessel prior to the start of the polymerization, a content inside the polymerization vessel during the polymerization, and the resulting polymer. According to the process, there is obtained a vinyl chloride polymer having a large bulk specific gravity and a fast gelation rate, and from the polymer, a formed part small in both the number of fish eyes and the amount of residual monomer can be obtained. |