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. 24, 1998
Filed:
Nov. 08, 1995
Toshihide Shimizu, Urayasu, JP;
Mikio Watanabe, Kamisu-machi, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A polymer scale preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline liquid containing a condensation product of: (A) at least one compound selected from the group consisting of azo compounds having at least two amino groups and azoxy compounds having at least two amino groups, and (B) a quirtone compound, is disclosed. Also disclosed is a process for producing a polymer, which comprises polymerizing the monomer in a polymerization vessel having a coating on its inner wall, whereby deposition of polymer scale is prevented, the coating having been formed by applying the scale preventive agent and drying the applied agent. According to the process, polymer scale deposition can be effectively prevented, not only on the areas located in the liquid-phase region but also on the areas around the gas-liquid interface in the vessel, so that the need to remove polymer scale every run of polymerization is eliminated and productivity is thereby enhanced. Besides, the process yields a polymer that shows few fish eyes and good whiteness when formed into sheets or the like.