Patents by Inventor Haruki Oikawa

Haruki Oikawa 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).

  • Patent number: 5043407
    Abstract: Hydrophilic fine gel particles, said particles being crosslinked polymer particles comprising 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.0% by weight of a crosslinkable ethylenically unsaturated monomer, 0.1-30% by weight of an ethylenically unsaturated carboxylic acid, 0.1-50% by weight of an ester monomer of an acrylic or methacrylic acid, and 0-30% by weight of a monomer copolymerizable with the above-mentioned monomers, said particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less; and a process for producing hydrophilic fine gel particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less, which comprises copolymerizing a monomer mixture of 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.
    Type: Grant
    Filed: July 24, 1990
    Date of Patent: August 27, 1991
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Jun Hasegawa, Haruki Oikawa, Osamu Kobayashi, Yasuo Kataoka, Masayoshi Sekiya
  • Patent number: 4988568
    Abstract: Hydrophilic fine gel particles, said particles being crosslinked polymer particles comprising 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.0% by weight of a crosslinkable ethylenically unsaturated monomer, 0.1-30% by weight of an ethylenically unsaturated carboxylic acid, 0.1-50% by weight of an ester monomer of an acrylic or methacrylic acid, and 0-30% by weight of a monomer copolymerizable with the above-mentioned monomers, said particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less; and a process for producing hydrophilic fine gel particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less, which comprises copolymerizing a monomer mixture of 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.
    Type: Grant
    Filed: March 28, 1989
    Date of Patent: January 29, 1991
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Jun Hasegawa, Haruki Oikawa, Osamu Kobayashi, Yasuo Kataoka, Masayoshi Sekiya