Patents by Inventor Yoshiyuki Doken

Yoshiyuki Doken 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).

  • Pitch fiber bundle and pitch type carbon fiber bundle and method for production thereof
    Patent number: 6524501
    Abstract: This invention provides a pitch fiber bundle for carbon fibers of small size, a carbon fiber bundle, and a method for the production thereof, i.e. a method for the production of carbon fibers of a small size, a pitch fiber bundle, and a carbon fiber bundle at a lower cost with higher productivity than usual. The method for the production of pitch type carbon fibers according to this invention comprises dividing a plurality of pitch fibers into not less than two bundles, intertwining the bundles by exposure to currents of air thereby forming a first fiber bundle, binding a plurality of such first fiber bundles, and again intertwining the bound pitch fiber bundles by exposure to currents of air thereby forming a second fiber bundle.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: February 25, 2003
    Assignees: Nippon Steel Corporation, Nippon Mitsubishi Oil Corporation, Nippon Graphite Fiber Corporation
    Inventors: Yutaka Arai, Yoshiyuki Doken, Tsutomu Nakamura
  • Pitch fiber bundle and pitch type carbon fiber bundle and method for production thereof
    Patent number: 6187434
    Abstract: This invention provides a pitch fiber bundle for carbon fibers of small size, a carbon fiber bundle, and a method for the production thereof, i.e. a method for the production of carbon fibers of a small size, a pitch fiber bundle, and a carbon fiber bundle at a lower cost with higher productivity than usual. The method for the production of pitch type carbon fibers according to this invention comprises dividing a plurality of pitch fibers into not less than two bundles, intertwining the bundles by exposure to currents of air thereby forming a first fiber bundle, binding a plurality of such first fiber bundles, and again intertwining the bound pitch fiber bundles by exposure to currents of air thereby forming a second fiber bundle.
    Type: Grant
    Filed: March 24, 2000
    Date of Patent: February 13, 2001
    Assignees: Nippon Steel Corporation, Nippon Mitsubishi Oil Corporation, Nippon Graphite Fiber Corporation
    Inventors: Yutaka Arai, Yoshiyuki Doken, Tsutomu Nakamura
  • Process for manufacturing pitch-type carbon fiber
    Patent number: 5968435
    Abstract: In a step of spinning a molten mesophase pitch in a process for manufacturing a pitch-type carbon fiber, the pitch is allowed to pass through an orifice and to be contracted once, is then expanded in an introduction port with a diameter greater than that of the orifice, and is then allowed to pass through an outlet pore formed at a collecting portion to spin the pitch. The pitch-type carbon fiber has a high elastic modulus in tension and high compressive strength.
    Type: Grant
    Filed: April 23, 1998
    Date of Patent: October 19, 1999
    Assignees: Nippon Steel Corporation, Nippon Steel Chemical Co., Ltd, Nippon Graphite Fiber Corporation
    Inventors: Osamu Kato, Yoshio Kishimoto, Yutaka Arai, Hajime Nakajima, Masatoshi Furuyama, Tsutomu Kihara, Michiharu Harakawa, Shigeo Hara, Ken Kobayashi, Yoshiyuki Doken, Tsutomu Nakamura