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:
Aug. 17, 2021
Filed:
May. 25, 2017
Kuraray Co., Ltd., Kurashiki, JP;
Takuma Kaneshima, College Station, TX (US);
KURARAY CO., LTD., Okayama, JP;
Abstract
The present invention provides an industrially advantageous method for producing vinyl alcohol polymers having a low degree of polymerization using a chain transfer agent having an aliphatic hydrocarbon group having 6 to 12 carbon atoms, the method being capable of producing a vinyl alcohol polymer whose aqueous solution has excellent viscosity stability. The present invention relates to a method for producing vinyl alcohol polymers, including: polymerizing a vinyl ester monomer (a) in the presence of a polymerization initiator (B) and a chain transfer agent (C) having an aliphatic hydrocarbon group having 6 to 12 carbon atoms to obtain a vinyl ester polymer (A); and saponifying the vinyl ester polymer (A) at a concentration of 40 mass % or more and 75 mass % or less in the presence of an acidic catalyst (D) to obtain a vinyl alcohol polymer, wherein the vinyl alcohol polymer has a viscosity-average degree of polymerization of 160 or more and 400 or less.