Dai-ichi Kogyo Seiyaku Co., Ltd.

Nippon Shokubai Co., Ltd.

Dai-chj Kogyo Seiyaki Co., Ltd.

Itsuko Hamaguchi

Keiichi Fujise

Akira Kitada

Akio Naka

Daijyo Tomihisa

Disclosed is a vinylpyrrolidone-based polymer composition which has improved storage stability and of which the reduction in the molecular weight (K value) under shear stress is small. The composition comprises a vinylpyrrolidone-based polymer and contains from 1 to 10000 ppm of at least one compound selected from a group consisting of biguanides and further contains from 1000 to 30000 ppm of 2-pyrrolidone and from 1 to 5000 ppm of ammonia.

Vinylpyrrolidone-based polymer composition

A process for preparing a high purity vinylpyrrolidone polymer which dissolves clearly in an organic solvent can be provided. The process for preparing a high purity vinylpyrrolidone polymer, wherein vinylpyrrolidone is polymerized by using a redox initiator comprising an organic peroxide and a sulfite, and thereafter the product is contacted with an anion exchange resin to be purified.

Process for preparing high-purity vinylpyrrolidone polymer

A vinylpyrrolidone polymer which is little colored, gives off a bad smell little, and contains extremely little impurities is provided. The polymerization is performed by adding a water-soluble organic peroxide and a sulfite to a vinylpyrrolidone aqueous solution.

Growing community of inventors

Kyoto, Japan

Itsuko Hamaguchi