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:
Feb. 08, 2000
Filed:
Apr. 29, 1997
Makoto Ooura, Ibaraki-ken, JP;
Kaname Inoue, Kawasaki, JP;
Masakuni Yamamoto, Kashiwa, JP;
Tadashi Amano, Ibaraki-ken, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
In a process for producing vinyl chloride polymers including polymerization of vinyl chloride or a monomer mixture containing it in an aqueous medium using a polymerization initiator, the polymerization is carried out in the presence of a chelating agent, The chelating agent is capable of chelating iron (II) and iron (III). This process makes it possible to prevent polymer scales from adhering to, e.g. baffle surfaces facing inner walls of the polymerization vessel, which has been hitherto difficult to do so, and less cause initial discoloration of polymer products to improve quality. It is more effective to use a polymerization vessel previously provided with coating films of a polymer scale preventive agent on the inner walls of the polymerization vessel and the other portions with which monomers come into contact in the course of polymerization.