Patents by Inventor Kazuyoshi Kuroishi

Kazuyoshi Kuroishi 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).

  • Rigid polyurethane foam and process for producing the same
    Patent number: 5216040
    Abstract: A rigid polyurethane foam obtained by foaming a special polyol component and an isocyanate component in the presence of a blowing agent comprising water and at least one member selected from the group consisting of 1,1-dichloro-2,2,2-trifluoroethane and 2,2-dichloro-2-monofluoroethane possesses balanced excellent properties, has no surface void, and shows only slight expansion after molding. Therefore, it can be effectively used as a heat insulator, in particular, a heat insulator for refrigerators.
    Type: Grant
    Filed: November 21, 1990
    Date of Patent: June 1, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Kazuyoshi Kuroishi, Reishi Naka, Isao Kobayashi, Kousuke Tanaka, Katuhiko Gotoo
  • Rigid polyurethane foam and heat insulator obtained therefrom
    Patent number: 5173517
    Abstract: A rigid polyurethane foam obtained by foaming a special polyol component and an isocyanate component using only water as a blowing agent has balanced excellent properties including a remarkably low density and a low thermal conductivity and is suitable for use as a heat insulator, particularly in a refrigerator.
    Type: Grant
    Filed: December 19, 1990
    Date of Patent: December 22, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Kazuyoshi Kuroishi, Reishi Naka, Isao Kobayashi
  • Rigid polyurethane foam, process for producing the same, and heat insulators and refrigerators using such polyurethane foam
    Patent number: 5034425
    Abstract: A rigid polyurethane foam produced by reacting a special polyol component with an isocyanate component in the presence of a blowing agent containing water in an amount of 2 to 3.5% by weight per 100% by weight of the polyol component is excellent in fluidity with balanced excellent properties.
    Type: Grant
    Filed: October 21, 1989
    Date of Patent: July 23, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Kazuyoshi Kuroishi, Reishi Naka, Isao Kobayashi
  • Rigid polyurethane foam and process for producing the same
    Patent number: 4742089
    Abstract: Rigid polyurethane foams produced by reacting a polyol component having a special composition with an isocyanate component in the presence of a blowing agent, a reaction catalyst and a foam stabilizer with a mold release time of as short as 5.5 minutes or less, have remarkably low thermal conductivity of 12.5.times.10.sup.-3 Kcal/m.hr..degree.C. or less and a low density and are suitable as heat insulating materials for refrigerators and the like.
    Type: Grant
    Filed: August 12, 1987
    Date of Patent: May 3, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Reishi Naka, Kazuyoshi Kuroishi
  • Rigid polyurethane foam and process for producing the same
    Patent number: RE33290
    Abstract: Rigid polyurethane foams produced by reacting a polyol component having a special composition with an isocyanate component in the presence of a blowing agent, a reaction catalyst and a foam stabilizer with a mold release time of as short as 5.5 minutes or less, have remarkably low thermal conductivity of 12.5.times.10.sup.-3 Kcal/m.hr..degree.C. or less and a low density and are suitable as heat insulating materials for refrigerators and the like.
    Type: Grant
    Filed: January 19, 1989
    Date of Patent: August 7, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Reishi Naka, Kazuyoshi Kuroishi