Kuraray Co., Ltd.

Yoko Nakano

Masato Nakamae

Masaki Kato

Tadahito Fukuhara

Yoshiaki Asanuma

Masao Tsuji

Kazuyuki Somemiya

Masako Katayama

Shigeo Ohzono

Makoto Nakazawa

Syunji Tago

Yoshiko Sho, Legal Representative

Yukiko Sho, Legal Representative

The present invention provides a modified vinyl alcohol polymer having a side chain with an ethylenic double bond, and having reduced a water-insoluble content and superior storage stability in the form of an aqueous solution, methods of making thereof, a modified vinyl alcohol polymer (A) having a degree of saponification of 68 mol % or more and less than 99.9 mol %, and a viscosity-average degree of polymerization of 200 or more and less than 3,000, and comprising a side chain with 0.01 mol % or more and less than 0.50 mol % of a double bond derived from an esterification agent, the esterification agent being one or more selected from the group consisting of (i) itaconic acid and/or derivatives thereof, and (ii) methacrylic acid and/or derivatives thereof, and the modified vinyl alcohol polymer (A) having a peak width Wof at least 2.85 minutes and less than 3.70 minutes at a height of 5% from the baseline in a peak measured by HPLC.

Modified vinyl alcohol polymer, method for producing same, dispersion stabilizer for suspension polymerization, and method for producing vinyl polymer

A composition including 100 parts by mass of a polyvinyl acetal and 30 to 70 parts by mass of a plasticizer including 0.5 to 100% by mass of a plasticizer containing a polar group and 0 to 99.5% by mass of a plasticizer containing no polar group, a total of the plasticizer containing a polar group and the plasticizer containing no polar group being 100% by mass. When the polyvinyl acetal is analyzed by HPLC using an ODS column having an inner diameter of 4 mm and a length of 1 cm, the polyvinyl acetal exhibits a first peak and a second peak derived from polyvinyl acetals. In addition, a laminated product of a layer including a polyvinyl acetal and a layer including a hydrocarbon-based polymer.

Polyvinyl acetal composition

7&#x3b1;-Hydroxy-pregn-4-en-3-one-20-carbaldehyde, a production method thereof and a method for producing 7&#x3b1;,21 -dihydroxy-20-methyl-pregn-4-en-3-one, which is useful as a synthetic intermediate for pharmaceuticals such as squalamine and the like, efficiently at high purity from the carbaldehyde.

7&#x3b1;-hydroxy-pregn-4-en-3-one-20-carbaldehyde, process for producing the same, and process for producing 7&#x3b1;, 21-dihydroxy-20-methyl-pregn-4-en-3-one from the same

The present invention provides a new dispersion stabilizer that satisfies, at a high level, the performances required for a dispersion stabilizer used for suspension polymerization. A method of producing a dispersion stabilizer that is useable for suspension polymerization of a vinyl compound and contains a vinyl alcohol polymer (A) includes producing the vinyl alcohol polymer (A) by heat-treating a vinyl alcohol polymer (B) at a temperature of 90 to 180&#xb0; C. for 0.5 to 20 hours in an atmosphere in which an oxygen concentration is 8000 ppm or lower. The vinyl alcohol polymer (B) has a saponification degree of at least 60 mol % and contains a residual acetic acid group whose block character is in the range of 0.3 to 0.6.

Dispersion stabilizer for suspension polymerization of vinyl compound and method of producing the same

Growing community of inventors

Kurashiki, Japan

Yoko Nakano