Invention Grant
- Patent Title: Method for producing vinyl alcohol polymers
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Application No.: US16304842Application Date: 2017-05-25
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Publication No.: US11091574B2Publication Date: 2021-08-17
- Inventor: Takuma Kaneshima
- Applicant: KURARAY CO., LTD.
- Applicant Address: JP Kurashiki
- Assignee: KURARAY CO., LTD.
- Current Assignee: KURARAY CO., LTD.
- Current Assignee Address: JP Kurashiki
- Agency: Morgan, Lewis & Bockius LLP
- Priority: JPJP2016-108920 20160531
- International Application: PCT/JP2017/019613 WO 20170525
- International Announcement: WO2017/208974 WO 20171207
- Main IPC: C08F2/38
- IPC: C08F2/38 ; C08F2/06 ; C08F4/34 ; C08F8/12 ; C08F216/06 ; C08F118/08

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.
Public/Granted literature
- US20200325259A1 METHOD FOR PRODUCING VINYL ALCOHOL POLYMERS Public/Granted day:2020-10-15
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