| 摘要 |
PURPOSE:Vinyl chloride monomer is additionally fed in the process of polymerization and partially saponified polyvinyl alcohol is added to give the titled polymer of a large bulk density and high plasticizer absorption with increased batch productivity. CONSTITUTION:An aqueous medium, a dispersant such as methylcellulose a polyumerization initiator such as acetylcyclohexylsulfonyl perioxide and vinyl chloride are charged in the polyhmerizer and the polymerization is initiated. Until polymerization conversion reaches 30-75%, vinyl chloride is additionally fed, further, a partially saponified polyvinyl alcohol of 200-1,500 polymerization degree and 30-75mol% saponification degree is added before, after or during additoinal charge, in an amount of 0.01-5wt% of the additionally charged monomer to complete the polymerization. EFFECT:The yield is increased without a large delay in polymerization time.
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