Patents by Inventor Kigen Kawai

Kigen Kawai 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: 6290888
    Abstract: The present invention provides a highly oriented aramid fiber with high tensile strength, high tensile modulus and low breakage elongation by spinning liquid crystal polymers such as aramids and drafting the polymer in or adjacent to a first coagulating bath. A polymer solution with concentration of 4-24 weight % is extruded as a stream into a non-coagulating fluid, and the stream is stretched in the non-coagulating fluid and passed through a first coagulating bath where it is drafted by using a drafting roller, so that the polymer concentration of the flue is increased sufficient to form fibers. As a result, a highly oriented aramid fiber with tensile strength of 1500-5000 MPa, tensile modulus of 200-500 GPa, and the % elongation of 0.8-1.4 is provided.
    Type: Grant
    Filed: August 4, 1999
    Date of Patent: September 18, 2001
    Assignee: Kansai Research Institute (KRI)
    Inventor: Kigen Kawai
  • Patent number: 5968432
    Abstract: A process of making a fiber includes the sequential steps of extruding as a stream solution of a polymer having a polymer concentration of 4-24 weight % into a non-coagulating fluid, stretching the stream while in the non-coagulating fluid, passing the stream through a first coagulating bath, stretching the stream in a non-coagulating fluid, and passing the stream through a coagulating bath to sufficiently increase the polymer concentration in the stream to form the fiber.
    Type: Grant
    Filed: March 4, 1997
    Date of Patent: October 19, 1999
    Assignee: Kansai Research Institute (KRI)
    Inventor: Kigen Kawai
  • Patent number: 5965260
    Abstract: The present invention provides a highly oriented aramid fiber with high tensile strength, high tensile modulus and low breakage elongation by spinning liquid crystal polymers such as aramids and drafting the polymer in or adjacent to a first coagulating bath. A polymer solution with concentration of 4-24 weight % is extruded as a stream into a non-coagulating fluid, and the stream is stretched in the non-coagulating fluid and passed through a first coagulating bath where it is drafted by using a drafting roller, so that the polymer concentration of the flue is increased sufficient to form fibers. As a result, a highly oriented aramid fiber with tensile strength of 1500-5000 MPa, tensile modulus of 200-500 GPa, and the % elongation of 0.8-1.4 is provided.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: October 12, 1999
    Assignee: Kansai Research Institute (KRI)
    Inventor: Kigen Kawai
  • Patent number: 5234651
    Abstract: A method of making a fiber involves the sequential steps of: a) extruding as a stream a solution of a polymer having a polymer concentration of 4-24 weight % into a non-coagulating fluid; b) stretching the stream while in the non-coagulating fluid at a spinning draft of 25-2000; c) increasing the polymer concentration by at least 2 weight % to a concentration of 20-65 weight %; e) stretching the stream at a stretch ratio of 1.5-10; and f) increasing the polymer concentration in the stream sufficiently to form a fiber.
    Type: Grant
    Filed: September 12, 1991
    Date of Patent: August 10, 1993
    Inventor: Kigen Kawai