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:
Jan. 23, 1979
Filed:
Apr. 18, 1977
Shunichi Koyanagi, Naoetsu, JP;
Shigenobu Tajima, Naoetsu, JP;
Kazuhiko Kurimoto, Nakakubiki, JP;
Yoshitaka Kiri, Takada, JP;
Shinetsu Chemical Company, Tokyo, JP;
Abstract
A polymerization vessel equipped with a condenser is charged with vinyl chloride, a suspending agent or dispersing agent, and water. The mixture is subjected to a preparatory stirring in the absence of a catalyst. The polymerization catalyst is added thereto when bubbling caused by the preparatory stirring subsides and stable suspended oil drops form. Blockage of the condenser by polymer scale deposition is substantially reduced. The addition of an alkaline substance, an oxidizing substance or an azine dye further reduces polymer scale deposition. Preferably the operation of the condenser is initiated only after the conversion rate is higher than 5% or the average value per unit hour.