Patents Represented by Law Firm Balogh, Osann, Kramer, Kvorak, Genova & Traub
  • Patent number: 4589975
    Abstract: A method of producing a precursor pitch for use in the production of carbon fibers, which comprises hydrogenating a soft or middle tar pitch to obtain a hydrogenated pitch containing no free carbon and high molecular weight components and then subjecting it to a heat treatment. In this method, the hydrogenation is carried out in the presence of tetralin at a temperature of 400.degree.-450.degree. C., and the heat treatment after the removal of solvent insoluble components and solvent is carried out in an inert gas atmosphere at a temperature of 450.degree.-500.degree. C. and under a reduced pressure of 0.1-10 Torr.
    Type: Grant
    Filed: December 27, 1984
    Date of Patent: May 20, 1986
    Inventors: Kozo Yudate, Yukihiro Ohsugi, Mamoru Kamishita, Ken Nagasawa