Patents by Inventor Syuji Iwakura

Syuji Iwakura 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 for preventing the discoloration of paper and paper treated to prevent discoloring
    Patent number: 5181988
    Abstract: A process for treating paper to prevent discoloration when exposed to light which comprises adding 1% to 10% by weight of hypophosphorous acid or its salt based on the paper at any stage during or after paper making and maintaining said hypophosphorous acid or its salt therein. The invention also provides paper which contains hypophosphorous acid or its salt to prevent discoloration when exposed to light.
    Type: Grant
    Filed: June 12, 1991
    Date of Patent: January 26, 1993
    Assignee: Asahi Denka Kogyo Kabushiki Kaisha
    Inventors: Mitsuo Akutsu, Syuji Iwakura
  • Heat-sensitive recording material
    Patent number: 5081099
    Abstract: A heat-sensitive recording material wherein a color-forming layer comprising a coupling substance which is usually colorless or light-colored and a developer which gives rise to color in the coupling substance upon heating further contains, as a sensitizer, a tetrahydronaphthalene compound of the following general formula (I): ##STR1## wherein X represents an alkylene group, --O--CO--O--, --O--CO-- or --O--R'.sub.n Y--, n represents 1 or 2, Y represents --O-- or --S--, R' represents an alkylene group, and R represents a phenyl, alkylphenyl or tetrahydronaphthyl group.
    Type: Grant
    Filed: July 19, 1990
    Date of Patent: January 14, 1992
    Assignee: Adeka Argus Chemical Co., Ltd.
    Inventors: Mitsuo Akutsu, Syuji Iwakura, Keiji Oya
  • Heat-sensitive recording material
    Patent number: 4980336
    Abstract: A heat-sensitive recording material wherein 1,2-bis(3,4-dimethylphenyl)ethane is contained as a sensitizer in a color-forming layer comprising a usually colorless or light-colored coupling substance and a developer which causes coloring of the coupling substance upon heating.
    Type: Grant
    Filed: October 27, 1989
    Date of Patent: December 25, 1990
    Assignee: Adeka Argus Chemical Co., Ltd.
    Inventors: Mitsuo Akutsu, Syuji Iwakura, Keiji Tabata, Keiji Oya
  • Optical recording material
    Patent number: 4944980
    Abstract: An optical recording material having excellent light stability, shelf stability and solubility in a solvent comprises, as an indispensable constituent, a compound of the following general formula: ##STR1## wherein R represents a cycloalkyl group having 3 to 12 carbon atoms, X.sup.- represents a halide anion, a perchlorate anion or a quencher anion, rings A and B each represent a benzene or naphthalene ring which may be substituted with a halogen atom, and n represents 1 to 4.
    Type: Grant
    Filed: July 25, 1989
    Date of Patent: July 31, 1990
    Assignee: Adeka Argus Chemical Co., Ltd.
    Inventors: Mitsuo Akutsu, Syuji Iwakura, Keiji Oya
  • Heat-sensitive recording material
    Patent number: 4918046
    Abstract: A heat-sensitive recording material which comprises a usually colorless or light-colored coloring material together with one or more compounds selected from among bissulfonate compounds, 2-substituted cyclohexyl sulfonate derivatives and biscycloalkyl aryldisulfonate derivatives.
    Type: Grant
    Filed: December 16, 1988
    Date of Patent: April 17, 1990
    Assignee: Adeka Argus Chemical Co., Ltd.
    Inventors: Mitsuo Akutsu, Syuji Iwakura, Keiji Oya, Keiji Tabata