Method for the suspension polymerization of vinyl chloride monomer

U.S. Patent Number: 5342906

Abstract: An improved method is proposed for the suspension polymerization of vinyl chloride monomer in an aqueous medium, by which the polyvinyl chloride resin obtained may have an increased bulk density without causing any disadvantages. The improvement can be obtained by controlling the power on the stirrer for the agitation of the polymerization mixture in such a manner that the power at the moment of the start of the polymerization reaction is 100 to 200 kgf.m/s per 1000 kg of the polymerization mixture and the power is subsequently decreased either continuously or step-wise according to a specified schedule down to 60 to 90% of the value at the start of the polymerization reaction at the moment when conversion of the monomer to polymer is 30% along with starting of the operation of the reflux condenser at a specified moment in relation to the stirrer power and the monomer conversion.

Inventors: Amano; Tadashi (Ibaraki, JP), Koga; Toshimichi (Ibaraki, JP)

Assignee: Shin-Etsu Chemical Co., Ltd. (Tokyo, JP)

Application Number: 08/060,596

Issued: 1994-08-30

Expired: 2006-08-30

Classes: 526/88 ; 526/202; 526/344.2

Field of search: 526/329.4,330,88

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