Kuraray Co., Ltd.

Yuki Tachibana

Kazuhiko Maekawa

Yusuke Amano

Yuki Shimizu

Keisuke Morikawa

Tadahito Fukuhara

Taeko Kaharu

Yuki Kosaka

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 from 95 to 99.99 mol %, and having an average particle diameter from 50 to 2000 μm. The production method does not cause the problem of the residual sulfur content derived from a liquid medium used for reaction and is also capable of modifying the vinyl alcohol-based polymer particles while maintaining the particle shape.

Production method for modified vinyl alcohol-based polymer particles and particles obtained using same

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.

Production method for modified vinyl alcohol polymer particle and particle obtained thereby

Release paper base paper includes a substrate; and a coating agent containing a modified polyvinyl alcohol (A) and sodium acetate, the substrate coated with the coating agent, wherein the modified polyvinyl alcohol (A) has 0.005 mol % or more and less than 10 mol % of double bonds derived from unsaturated carboxylic acid or a derivative thereof (B) in side chains, has 1.4 mol % or more and 2.0 mol % or less of 1,2-glycol bond, units, and is water soluble, and a content of the sodium acetate relative to the modified polyvinyl alcohol (A) is 0.01 mass % or more and 10 mass % or less. The release paper base paper of the present invention is excellent in sealing properties for silicone. Use of the release paper base paper allows acceleration of curing of silicone in a release layer and improvement in adhesion between the substrate and the release layer.

Release-paper base paper and method for producing same, and release paper

The invention relates to particles with an average particle size of 300 to 1000 &#x3bc;m, comprising a modified polyvinyl alcohol having vinyl alcohol units and structural units represented by formula (1), wherein a content of the vinyl alcohol units is 60 to 90 mol % based on the total structural units: 

Particles containing modified polyvinyl alcohol

There is provided a vinyl alcohol-based polymer having an olefin in side chain, comprising 0.001 to 10 mol % of a structural unit represented by Formula (1) based on the total amount of structural units, wherein the total carbon number of X, R, R, Rand Ris 2 or more. The vinyl alcohol-based polymer having an olefin in side chain has excellent storage stability, good solubility in water or an organic solvent even after thermal treatment, and excellent reactivity to high energy beam. In Formula (1), X represents an optionally substituted divalent aliphatic hydrocarbon group, an optionally substituted divalent alicyclic hydrocarbon group, an optionally substituted divalent aromatic hydrocarbon group, or a group consisting of two or more of these groups which are linked via at least one bond selected from the group consisting of an amide bond, an ester bond, an ether bond, and a sulfide bond; R, R, Rand R, independently of each other, represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an optionally substituted alicyclic hydrocarbon group, or an optionally substituted aromatic hydrocarbon group; and X, R, R, Rand Rcan be arbitrarily combined to form a ring structure). 

Vinyl alcohol-based polymer having olefin in side chain

The present invention relates to a vinyl alcohol-based polymer having an olefin in side chain, comprising a vinyl alcohol unit and a structural unit represented by Formula (I), wherein X represents a divalent saturated hydrocarbon group with 1 to 6 carbon atoms, optionally having a branched structure; Y represents a hydrogen atom or a saturated hydrocarbon group with 1 to 6 carbon atoms, optionally having a branched structure; and Z represents a hydrogen atom or a methyl group. Thus, there is provided a vinyl alcohol-based polymer having an olefin in side chain exhibiting higher water solubility even after thermal treatment, higher storage stability, and higher reactivity to high energy beam, and a method for producing it. 

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Kurashiki, Japan

Yuki Tachibana