Patents by Inventor Hitoshi Shiiki

Hitoshi Shiiki 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).

  • Polypropylene resin pre-expanded beads, manufacturing method thereof and expansion-molding method using said beads
    Patent number: 5017621
    Abstract: The present invention provides polypropylene resin pre-expanded beads formed by shrinking polypropylene resin pre-expanded beads originally having a bulk density of not higher than 0.0930 g/cc to give them a bulk volume ratio of 10-75% at normal temperature and normal pressure, a manufacturing method thereof and an expansion-molding method with the aforementioned pre-expanded beads. According to this invention, it is possible to greatly reduce storing and transporting costs per unit weight of pre-expanded beads.
    Type: Grant
    Filed: March 22, 1990
    Date of Patent: May 21, 1991
    Assignee: Kanegafuchi Kagaku Kogyo Kabushiki Kaisha
    Inventors: Hitoshi Shiiki, Minoru Tada, Kyoichi Nakamura
  • Polypropylene resin pre-expanded beads, manufacturing method thereof and expansion-molding method using said beads
    Patent number: 4931477
    Abstract: The present invention provides polypropylene resin pre-expanded beads formed by shrinking polypropylene resin pre-expanded beads originally having a bulk density of not higher than 0.0930 g/cc to give then a bulk volume ratio of 10-75% at the normal temperature and the normal pressure, a manufacturing method thereof and an expansion-molding method with the aforementioned pre-expanded beads. According to this invention, it is possible to greatly reduce storing and transporting costs per unit weight of pre-expanded beads.
    Type: Grant
    Filed: December 9, 1988
    Date of Patent: June 5, 1990
    Assignee: Kanegafuchi Kagaku Kogyo Kabushiki Kaisha
    Inventors: Hitoshi Shiiki, Minoru Tada, Kyoichi Nakamura