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AssigneeKuraray Co., Ltd.
InventorsYuki TACHIBANA, Yusuke AMANO, Yuki SHIMIZU, Kazuhiko MAEKAWA
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A method of producing modified vinyl alcohol-based polymer particles, includes mixing vinyl alcohol-based polymer particles with a mixed medium containing 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 containing a vinyl ester unit represented by a formula (2) below, having a vinyl alcohol unit content based on the total constitutional units of 60 mol % or more and less than 95 mol %, and having an average particle diameter from 50 to 2000 μm. The production method is capable of controlling the particle shape and does not cause the problem of the residual sulfur content, and is further convenient and economically advantageous.
A method for producing modified vinyl alcohol-based polymer particles, the method comprising:
Modified vinyl alcohol-based polymer particles comprising a vinyl ester unit, wherein a ratio of three or more consecutive vinyl ester units to a total vinyl ester units is 30% or less, a vinyl alcohol unit content based on a total constitutional units is 60 mol % or more and less than 95 mol %, and an average particle diameter is from 50 to 2000 μm, and the vinyl ester unit is a unit of formula (2):
ng to claim 8, wherein a sulfur content is from 0.01 to 20000 ppm.
The modified vinyl alcohol-based polymer particles
Dependencies are inferred from the claim text.