PRODUCTION OF HIGH-BULK-SPECIFIC-GRAVITY VINYL CHLORIDE-BASED POLYMER

PROBLEM TO BE SOLVED: To produce a high bulk specific gravity vinyl chloride-based polymer without complicatedness in production. SOLUTION: This invention provides a process for producing a vinyl chloride- based polymer having a bulk specific gravity of 0.58 g/cc or above, wherein a dispersant comprising (A) to (C) in amounts to give an A/C weight ratio in the range of 1/2 to 2/1, and 1-4 wt.%, based on the total weight of components A to C, component C by suspension polymerization. (A) a partially saponified polyvinyl alcohol having a degree of saponification of 97 mol.% or above and a viscosity of 40-70 cP (as measured in a 4 wt.% aqueous solution at 20 deg.C), (B) a partially saponified polyvinyl alcohol having a degree of saponification of 75-85 mol.% and a viscosity of 20-70 cP (as measured in a 4 wt.% aqueous solution at 20 deg.C), and (C) a hydroxypropylmethylcellulose containing 19-30 mol.% methoxyl groups and 4-12 mol.% propoxyl groups and having a viscosity of 20-120 cP (as measured in a 2 wt.% aqueous solution as 20 deg.C).