公开(公告)号：CA1254327A

公开(公告)日：1989-05-16

申请号：CA452764

申请日：1984-04-25

Applicant: STAMICARBON

Inventor： TUYT ROBERT C ,  EVENS GEORGES G ,  MEYER PETER J N ,  PONS DICK A

IPC: C08F2/00 ,  C08F2/18 ,  C08F2/20 ,  C08F2/44 ,  C08F14/06

Abstract: 22772-1007 The invention relates to a process for preparing vinyl chloride polymers by suspension polymerization in a polymerization reactor of vinyl chloride, optionally in combination with at most 30 % (wt) of one or more monomers copolymerizable therewith, with monomer - soluble, radical - forming initiators and possibly in the presence of primary suspending agents. The improvement comprises the addition of an aqueous dispersion of at least one polyvinyl ester with a degree of solvolysis in respect of the dry substance lower than 25 moles % to the polymerizetion reactor before or during said polymerization, which polyvinyl ester is chosen from the polymeric vinyl esters of aliphatic and/or aromatic carboxylic acids, the amount of the aqueous dispersion supplied being such that after this addition the reaction mixture contains 0.01-0.5 part by weight of the polyvinyl ester per 100 parts by weight of the starting monomer.

公开(公告)号：CA1243795A

公开(公告)日：1988-10-25

申请号：CA452765

申请日：1984-04-25

Applicant: STAMICARBON

Inventor： TUYT ROBERT C ,  EVENS GEORGES G ,  MEYER PETER J N ,  PONS DICK A

IPC: C08F2/00 ,  C08F2/18 ,  C08F2/20 ,  C08F2/44 ,  C08F14/06

Abstract: The invention relates to a process for preparing vinyl chloride polymers by suspension polymerization in a polymerization reactor of vinyl chloride, optionally in combination with at most 30 % (wt) of one or more monomers copolymerizable therewith, with monomer-soluble, radicalforming initiators and optionally in the presence of primary suspending agents. The improvement comprises the addition of 0.01-0.5 part by weight of at least one polyvinyl ester with an average degree of solvolysis lower than 70 moles % per 100 parts by weight of the starting monomer to the polymerization reactor before or during this polymerization, which polyvinyl ester is chosen from the polymeric vinyl esters of aliphatic and/or aromatic carboxylic acids with 3-20 C-atoms per molecule. The process enables production of polymers with lower fish-eye numbers.