| 摘要 |
PURPOSE:To prevent the scale deposition in a polymerizer and obtain the titled polymer having a constant quality, by prepolymerizing vinyl chloride monomer in the polymerizer having an agitator under specific conditions, and mass polymerizing the resultant prepolymer in a special polymerizer with a low moisture content. CONSTITUTION:(A) Vinyl chloride monomer or a monomer mixture consisting essentially thereof, (B) 0.001-3wt%, based on the component (A), antistatic agent and (C) a polymerization initiator are charged into a polymerizer having an agitator and prepolymerized to give 5-30% conversion while keeping the moisture content in the polymerizer at <=0.04wt% based on the component (A). The above-mentioned prepolymer mixture is then mass polymerized in a cylindrical polymerizer having an agitator in which the minimum distance between the inner sidewall of the polymerizer and the outer edge of the agitating blades is <=mm. all over the above-mentioned wall while keeping the total moisture at <=0.04wt% based on the component (A) to give the aimed polymer.
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