Patents by Inventor Tadashi Koyonagi

Tadashi Koyonagi 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: 5281476
    Abstract: A crimped multifilament composed of a thermoplastic polymer, wherein a birefringence index measured at an outer layer of a filament constituting said multifilament is larger than that of a birefringence index measured at a central portion of the filament, and said filament has a distribution in which a position having a smallest value of the birefringence index deviates from the center axis of the filament and random crimps of 10 per inch or more.A crystal growth rate measured by a wide-angle X-ray diffractometry is 0.2 or more for a polyamide crimped multifilament and 0.4 or more for a polyester crimped multifilament.A preferable method for manufacturing the crimped multifilament is that a multifilament extruded from. a spinneret (2) is applied with an aqueous liquid (5) to one side thereof up to state that a temperature of the multifilament becomes to a predetermined temperature, the obtained multifilament is drawn at the drawing ratio between 1.0 and 1.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: January 25, 1994
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Tadashi Koyonagi, Hironori Hamada, Yumio Endoh, Teruhiko Matsuo