US 11,884,756 B2
Production method for modified vinyl alcohol polymer particle and particle obtained thereby
Yuki Tachibana, Kurashiki (JP); Yusuke Amano, Kurashiki (JP); Yuki Shimizu, Kurashiki (JP); and Kazuhiko Maekawa, Kurashiki (JP)
Assigned to KURARAY CO., LTD., Kurashiki (JP)
Appl. No. 17/418,468
Filed by KURARAY CO., LTD., Kurashiki (JP)
PCT Filed Dec. 26, 2019, PCT No. PCT/JP2019/051112
§ 371(c)(1), (2) Date Jun. 25, 2021,
PCT Pub. No. WO2020/138284, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 2018-248264 (JP), filed on Dec. 28, 2018.
Prior Publication US 2022/0089793 A1, Mar. 24, 2022
Int. Cl. C08F 16/06 (2006.01); C08J 7/16 (2006.01)
CPC C08F 16/06 (2013.01) [C08J 7/16 (2013.01); C08F 2810/00 (2013.01); C08J 2329/04 (2013.01)] 20 Claims
 
1. A method for producing modified vinyl alcohol-based polymer particles, the method comprising:
mixing vinyl alcohol-based polymer particles with a mixed medium comprising an unsaturated carboxylic acid, an acid catalyst, and water, wherein by mixing the vinyl alcohol-based polymer particles with the mixed medium, the vinyl alcohol-based polymer particles are reacted with the unsaturated carboxylic acid to obtain modified vinyl alcohol-based polymer particles comprising a vinyl ester unit, having a vinyl alcohol unit content based on a total constitutional units of 60 mol % or more and less than 95 mol %, and having an average particle diameter from 50 to 2000 μm,
wherein the unsaturated carboxylic acid is a compound of formula (1):

OG Complex Work Unit Chemistry
wherein X denotes a carbon-carbon bond or a divalent saturated hydrocarbon group having a carbon number from 1 to 10 optionally having a branched structure, Y denotes a hydrogen atom or a saturated hydrocarbon group having a carbon number from 1 to 6 optionally having a branched structure, and Z denotes a hydrogen atom or a methyl group, and
the vinyl ester unit is a unit of formula (2):

OG Complex Work Unit Chemistry