Shin-etsu Chemical Co., Ltd.

Hajime Kutamura

Toshihide Shimizu

Ichiro Kaneko

Shunichi Koyanagi

A process for production of a vinyl polymer by suspension polymerization or emulsion polymerization of at least one kind of vinyl monomer in an aqueous medium is disclosed. In this process, the polymerization is carried out in a polymerizer, the inner wall surface and portions of the auxiliary equipment thereof which may come into contact with the monomer during polymerization having a surface roughness of not greater than 5 .mu.m and being previously coated with a scaling preventive comprising at least one selected from dyes, pigments and aromatic or heterocyclic compounds having at least 5 conjugated .pi. bonds. According to this process, scaling on the inner wall surface of a polymerizer, etc. during polymerization can be prevented effectively and surely.

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Ichihara, Japan

Hajime Kutamura