Patents by Inventor Nubohito Koga

Nubohito Koga 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).

  • Production process for polyimide fibers
    Patent number: 4994544
    Abstract: A process for the production of polyimide fibers and polyimide fibers obtained by the process. The process includes thermal or chemical imidation of a polyamic acid which has been obtained by reacting a specific diamine and a particular tetracarboxylic dianhydride in the presence of a dicarboxylic anhydride represented by the following formula: ##STR1## wherein Z represents a divalent group selected from the group consisting of monocyclic aromatic groups, fused polycyclic aromatic groups and non-fused polycyclic aromatic groups with aromatic rings bonded together directly or via a crosslinking member.
    Type: Grant
    Filed: November 6, 1989
    Date of Patent: February 19, 1991
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Taizo Nagahiro, Masahiro Ohta, Shuichi Morikawa, Nubohito Koga, Shoji Tamai