| 摘要 |
PROBLEM TO BE SOLVED: To obtain a vinyl chloride polymer high in degree of polymn. with a high productivity while decreasing the load of heat removal by starting polymn. of at most 4/5 of all vinyl chloride monomer of be charged in a polymerizer in the presence of a polymn. initiator, and feeding and polymerizing the rest of the monomer after the inner pressure begins to lower. SOLUTION: A 1,1,2,2-tetramethylpropyl peroxyester of formula I (wherein R<1> to R<3> are each a 1-9C linear alkyl) having a 10-hr half-life temp. of 30 to 65 deg.C as measured in a 0.1mol/l soln. thereof in benzene is used in an amt. of 0.01 to 0.3wt.% based on all of a monomer to be charged. At most 4/5 of all the monomer to be charged is charged in a polymerizer, wherein polymn. is allowed to proceed under a given satd. vapor pressure P1 kgf/cm<2> at a set polymn. temp. When the inner pressure of the polymerizer is lowered to P2 kgf/ cm<2> , the rest of the monomer is added while maintaining the inner pressure of the polymerizer in the range of P1 -ΔP (whereinΔP=P1 -P2 , and 0.1kg.f/ cm<2> <=ΔP<=2.0kg.f/cm<2> ).
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