Patents by Inventor Itsuko Hamaguchi

Itsuko Hamaguchi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Vinylpyrrolidone-based polymer composition
    Patent number: 7700674
    Abstract: 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.
    Type: Grant
    Filed: July 31, 2007
    Date of Patent: April 20, 2010
    Assignees: Nippon Shokubai Co., Ltd., Dai-Chj Kogyo Seiyaki Co., Ltd.
    Inventors: Keiichi Fujise, Itsuko Hamaguchi, Akio Naka, Daijyo Tomihisa
  • Vinylpyrrolidone-based polymer composition
    Publication number: 20080033081
    Abstract: 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.
    Type: Application
    Filed: July 31, 2007
    Publication date: February 7, 2008
    Inventors: Keiichi Fujise, Itsuko Hamaguchi, Akio Naka, Daijyo Tomihisa
  • Process for preparing high-purity vinylpyrrolidone polymer
    Patent number: 6486281
    Abstract: 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.
    Type: Grant
    Filed: August 24, 2001
    Date of Patent: November 26, 2002
    Assignee: Dai-Ichi Kogyo Seiyaku Co., Ltd.
    Inventors: Akira Kitada, Keiichi Fujise, Itsuko Hamaguchi
  • PROCESS FOR PREPARING VINYLPYRROLIDONE POLYMER
    Publication number: 20020173608
    Abstract: 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.
    Type: Application
    Filed: August 3, 2001
    Publication date: November 21, 2002
    Inventors: Akira Kitada, Keiichi Fujise, Itsuko Hamaguchi
  • Process for preparing vinylpyrrolidone polymer
    Patent number: 6465592
    Abstract: 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.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: October 15, 2002
    Assignee: Dai-Ichi Kogyo Seiyaku Co., Ltd.
    Inventors: Akira Kitada, Keiichi Fujise, Itsuko Hamaguchi