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:
May. 13, 2025
Filed:
Dec. 23, 2020
Showa Denko K.k., Tokyo, JP;
Takamitsu Kobayashi, Tokyo, JP;
Naoyuki Tanaka, Tokyo, JP;
Resonac Corporation, Tokyo, JP;
Abstract
A method for producing a highly polymerizable N-vinyl carboxylic acid amide monomer includes (A) melting a crude N-vinyl carboxylic acid amide monomer comprising 50 to 88 mass % of an N-vinyl carboxylic acid amide monomer by heating, followed by cooling for precipitation, and subjecting precipitated N-vinyl carboxylic acid amide monomer crystals to solid-liquid separation (step (A)), and (B) further dissolving the N-vinyl carboxylic acid amide monomer crystals separated in step (A) in a mixed solvent of toluene and an aliphatic hydrocarbon having 6 to 7 carbon atoms, then performing crystallization, performing solid-liquid separation, and recovering an N-vinyl carboxylic acid amide monomer purified product (step (B)), wherein a mass ratio of toluene/N-vinyl carboxylic acid amide monomer crystal in step (B) is 0.01 to 0.5, and a mass ratio of aliphatic hydrocarbon having 6 to 7 carbon atoms/N-vinyl carboxylic acid amide monomer crystal in step (B) is 0.5 to 3.0.