Patents by Inventor Takasi Ohkawa

Takasi Ohkawa 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).

  • Method of preventing discoloring of maleic anhydride
    Patent number: 5157130
    Abstract: A monochloro-substituted aliphatic alcohol containing 3-8 carbon atoms, a copper compound and a zinc compound are added to maleic anhydride to prevent discoloration of the maleic anhydride. Deterioration of the quality of the maleic anhydride can be inhibited when it is stored for a long period of time or heat-melted.
    Type: Grant
    Filed: June 20, 1990
    Date of Patent: October 20, 1992
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Harusige Sugawara, Takasi Ohkawa