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. 24, 2002
Filed:
Nov. 20, 2001
Masahiro Usuki, Kamisu-machi, JP;
Minoru Shigemitsu, Kamisu-machi, JP;
Tadashi Amano, Kamisu-machi, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
Vinyl chloride or a monomer mixture containing it transported over a long distance or stored for a long period usually contains a polymerization inhibitor and Fe ions. If this kind of vinyl chloride or monomer mixture is polymerized, stirring torque during the polymerization increases, and heat removal by the cooling jacket of a polymerization vessel tends to become insufficient, making the polymer quality subject to bad influences. In the present invention, a hydroxycarboxylic acid compound is added to the polymerization mixture in an amount of 50-1000 ppm relative to the monomer or monomer mixture. As a result, an increase in stirring torque during polymerization is suppressed, and heat removal by the cooling jacket of the polymerization vessel can be performed effectively, making it possible to obtain vinyl chloride of good quality.