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:
Dec. 14, 2021
Filed:
Mar. 16, 2018
Zeon Corporation, Tokyo, JP;
Tsutomu Yoshimura, Tokyo, JP;
ZEON CORPORATION, Tokyo, JP;
Abstract
A method for producing a carboxyl group-containing nitrile rubber including the steps of: polymerizing a monomer mixture including an α,β-ethylenically unsaturated nitrile monomer and a carboxyl group-containing monomer in a solvent; terminating a polymerization reaction by adding a nitrous acid salt and a water-insoluble hydroquinone as polymerization terminators to the polymerization system, thereby obtaining a dispersion of the carboxyl group-containing nitrile rubber having a pH of 7 or below; and coagulating the dispersion of the carboxyl group-containing nitrile rubber, thereby obtaining the carboxyl group-containing nitrile rubber in the solid state, wherein the amount of the nitrous acid salt to be used is 0.15 parts by weight or less relative to 100 parts by weight of the monomer mixture used in the polymerization reaction.