Patents by Inventor Kazuharu Itoh

Kazuharu Itoh 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).

  • Propylene-based polymer, method for its production, composition thereof, catalyst component for polymerization, and method for its production
    Patent number: 6323298
    Abstract: There are provided a propylene-based polymer characterized in that (1) the xylene-extraction insoluble portion (XI) is 99.0 wt % or greater, (2) the isotactic pentad ratio (IP) is 98.0% or greater as measured by 13C nuclear magnetic resonance spectroscopy, (3) the isotactic average chain length (N) is 500 or greater, and (4) the total amount of each of the fractions obtained by column separation of the xylene insolubles whose average chain length (Nf) is 800 or greater accounts for 10 wt % or more of the entirety, and a method for its production, as well as a propylene-based polymer composition prepared by combining with this propylene-based polymer at least a nucleating agent in the range of 0.05-15 wt %. In addition, there are provided a polymerization catalyst component allowing the production of such a propylene-based polymer, and a method for its production.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: November 27, 2001
    Assignee: Showa Denko K.K.
    Inventors: Hisayoshi Yanagihara, Kazuyuki Watanabe, Satoshi Iwamoto, Hirotoshi Takahashi, Kazuharu Itoh
  • Propylene-based polymer, method for its production, composition thereof, catalyst component for polymerization, and method for its production
    Patent number: 6184328
    Abstract: There are provided a propylene-based polymer characterized in that (1) the xylene-extraction insoluble portion (XI) is 99.0 wt % or greater, (2) the isotactic pentad ratio (IP) is 98.0% or greater as measured by 13C nuclear magnetic resonance spectroscopy, (3) the isotactic average chain length (N) is 500 or greater, and (4) the total amount of each of the fractions obtained by column separation of the xylene insolubles whose average chain length (Nf) is 800 or greater accounts for 10 wt % or more of the entirety, and a method for its production, as well as a propylene-based polymer composition prepared by combining with this propylene-based polymer at least a nucleating agent in the range of 0.05-15 wt %. In addition, there are provided a polymerization catalyst component allowing the production of such a propylene-based polymer, and a method for its production.
    Type: Grant
    Filed: December 8, 1998
    Date of Patent: February 6, 2001
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Hisayoshi Yanagihara, Kazuyuki Watanabe, Satoshi Iwamoto, Hirotoshi Takahashi, Kazuharu Itoh
  • Propylene-based polymer, method of its production, composition thereof, catalyst component for polymerization, and method for its production
    Patent number: 5916990
    Abstract: There are provided a propylene-based polymer characterized in that (1) the xylene-extraction insoluble portion (XI) is 99.0 wt % or greater, (2) the isotactic pentad ratio (IP) is 98.0% or greater as measured by .sup.13 C nuclear magnetic resonance spectroscopy, (3) the isotactic average chain length (N) is 500 or greater, and (4) the total amount of each of the fractions obtained by column separation of the xylene insolubles whose average chain length (N.sub.f) is 800 or greater accounts for 10 wt % or more of the entirety, and a method for its production, as well as a propylene-based polymer composition prepared by combining with this propylene-based polymer at least a nucleating agent in the range of 0.05-15 wt %. In addition, there are provided a polymerization catalyst component allowing the production of such a propylene-based polymer, and a method for its production.
    Type: Grant
    Filed: September 7, 1994
    Date of Patent: June 29, 1999
    Assignee: Showa Denko K.K.
    Inventors: Hisayoshi Yanagihara, Kazuyuki Watanabe, Satoshi Iwamoto, Hirotoshi Takahashi, Kazuharu Itoh