Process for producing a vinyl chloride-based polymer.

摘要

A process for producing a vinyl chloride-based polymer by suspension polymerizing vinyl chloride monomer or the like while circulating a reaction mixture in a polymerization vessel by a circulating pump through a circulation line led out from the polymerization vessel to extend through a heat exchanger back to the vessel, wherein the pump comprises a conical hub (15) and an impeller comprised of a spirally shaped single blade (16) provided on the hub (15), and, during polymerization, the stirring energy (A) applied to the reaction mixture by the stirrer in the polymerization vessel and the circulating energy (B) exerted to the reaction mixture by the circulating pump in the circulation line are controlled so as to satisfy the relationships: (A) + (B) = from 1.5 to 4.0 kW/t (1), and (B) / [(A) + (B)] = from 0.1 to 0.6 (2). Polymer scale is prevented from being deposited on inner surfaces of the heat exchanger, circulation piping, circulating pump or the like.