The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 2004
Filed:
Mar. 05, 2002
Toshihiko Kawakubo, Kashima-gun, JP;
Tadashi Amano, Kashima-gun, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A process for polymerizing vinyl chloride or a monomer mixture containing vinyl chloride in an aqueous medium in a polymerization vessel fitted with a reflux condenser, characterized by starting to add (A) an anti-foam agent, and (B) a partially saponified polyvinyl alcohol with an average degree of polymerization of 100 to 500 and a saponification degree of 75 to 85 mole %, to a reaction mixture during the operation of said reflux condenser, and continuing the addition of (A) and (B) until recovery of unreacted monomers from said polymerization vessel is completed, thereby preventing the polymer slurry from foaming, rising, or scattering during polymerization or recovery of unreacted monomers.