Kuraray Co., Ltd.

Junpei Horiguchi

Tadahito Fukuhara

Yosuke Kumaki

Shinsuke Nii

Tatsuya Tanida

Junji Funakoshi

Kazuyuki Tanaka

A modified vinyl alcohol polymer powder having a structural unit derived from a derivative of an ethylenically unsaturated dicarboxylic acid, and containing a reduced amount of methanol, and a trace amount of a component that does not dissolve in water. The present invention relates to a modified vinyl alcohol polymer powder containing a structural unit derived from a derivative (A) of an ethylenically unsaturated dicarboxylic acid in a content (X) of 0.05 mol % or more and 10 mol % or less, and having a degree of saponification of 80.0 mol % or more and 99.9 mol % or less, the modified vinyl alcohol polymer powder has a methanol content of 0.01 weight % or more and less than 3.0 weight %, the modified vinyl alcohol polymer powder contains 0.1 ppm or more and less than 2,000 ppm of a component that is insoluble in a 90&#xb0; C., 5 weight % aqueous solution.

Modified vinyl alcohol polymer powder having reduced methanol content and production method therefor, and water-soluble film and packaging material

The present invention is characterized by being a polyvinyl alcohol powder having an average particle diameter of 100 to 2000 &#x3bc;m as measured by optical microscopic observation at a humidity of 65% RH and a temperature of 25&#xb0; C., having a bulk specific gravity (g/ml) of a portion ranging from 500 to 1000 &#x3bc;m in particle diameter of more than 0.60 and less than 0.80, and having a content of the portion ranging from 500 to 1000 &#x3bc;m in particle diameter of 35 to 70% by mass. Accordingly, a polyvinyl alcohol powder is provided, that is good in anti-scattering property, superior in solubility in preparing an aqueous solution from the powder, and capable of reducing transport costs due to its large specific gravity.

Polyvinyl alcohol powder and method for producing same

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Tainai, Japan

Junpei Horiguchi