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:
Sep. 10, 2002
Filed:
Jan. 19, 2001
Takashi Kobayashi, Kamisu-machi, JP;
Ryuichi Saito, Kamisu-machi, JP;
Yoshinori Nakahara, Kamisu-machi, JP;
Tadashi Amano, Kamisu-machi, JP;
Ichiro Hara, Hasaki-machi, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A process for producing a vinyl chloride polymer, including the steps of (a) subjecting a vinyl chloride monomer alone or a monomer mixture containing a vinyl chloride, to suspension polymerization in water; (b) subjecting the resultant vinyl chloride polymer slurry to stripping to remove an unreacted monomer remaining therein; and (c) dehydrating the polymer slurry having been subjected to stripping. In the polymerization step (a), the ratio of water/monomer is set in a weight ratio of from 0.80 to 1.50, and the viscosity at 20° C. of the polymer slurry to be fed to the stripping step is previously kept adjusted to 0.30 Pa·s or lower. In the stripping step (c), the residual unreacted monomer in the polymer slurry can efficiently be removed using steam in a smaller quantity, thus the vinyl chloride polymer can be produced at a high productivity.