Patents by Inventor Hiroshi Okayasu

Hiroshi Okayasu 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).

  • Process for producing dioxazine violet pigment
    Patent number: 4804417
    Abstract: Dioxazine violet pigment clear in color hue, high in tinting strength and good in dispersibility, which is suitable for ink, is prepared by treating a crude dioxazine violet with sulfuric acid (to finer it) and then treating an aqueous suspension of the resulting dioxazine violet in coexistence of an alcohol and an inorganic salt.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: February 14, 1989
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Taira Fujita, Yoshiaki Hayashi, Hiroshi Okayasu
  • Process for producing copper phthalocyanine pigment
    Patent number: 4785091
    Abstract: Copper phthalocyanine pigment which is a coloring material for ink or paint is prepared by allowing, for example, phthalate, urea, and cuprous chloride to react in a hydrophilic solvent in the presence of a catalyst and at least one element selected from the group consisting of aliphatic tetracarboxylic acids, benzophenone 3,3',4,4'-tetracarboxylic acid or anhydride thereof, pyromellitic acid or anhydride thereof, copper phthalocyanine sulfonic acids, copper phthalocyanine carbonyl imide, tetrahydrophthalic acid or derivative thereof, pyromellitic imide or derivative thereof, sulfophthalic acid, derivative thereof or the salt thereof and benzene carboxylic acid.
    Type: Grant
    Filed: October 20, 1987
    Date of Patent: November 15, 1988
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Taira Fujita, Toshiaki Kishimoto, Hiroshi Okayasu