Patents by Inventor Toshiaki Imokawa

Toshiaki Imokawa 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 preparing liquid diphenylmethane diisocyanate
    Patent number: 5610408
    Abstract: A process for preparing a liquid MDI, which comprises adding, to MDI, a phospholine catalyst and a phosphorous acid ester of a specified formula and conducting a carbodiimidization reaction.
    Type: Grant
    Filed: August 28, 1995
    Date of Patent: March 11, 1997
    Assignee: Sumitoma Bayer Urethane Co., Ltd.
    Inventors: Toshiaki Imokawa, Yoshiharu Kato
  • Method for preventing coloration of aromatic isocyanate compounds
    Patent number: 5258548
    Abstract: A method for preventing coloration of an aromatic isocyanate compound, which is characterized in that an organic phosphite ester of formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are, the same or different, each a C.sub.4-20 hydrocarbon group, 2,6-di-tert.-butyl-4-methylphenol and triphenyl phosphite are added to the aromatic isocyanate compound.
    Type: Grant
    Filed: September 3, 1992
    Date of Patent: November 2, 1993
    Assignee: Sumitomo Bayer Urethane Co., Ltd.
    Inventor: Toshiaki Imokawa
  • Low-viscosity polyol composition containing potassium titanate needle crystal
    Patent number: 5096956
    Abstract: A polyol composition with a viscosity at 25.degree. C. of not higher than 50,000 cps which comprises (1) 100 parts by weight of a polyether polyol with a molecular weight of 2,000 to 10,000 prepared by addition of ethylene oxide and propylene oxide to a di- or tri-functional compound containing active hydrogen atoms, (2) 5 to 30 parts by weight of an aromatic diamine, (3) a solution of 0.5 to 5 parts by weight of fatty acid metal salt in an aliphatic amine and (4) 10 to 50 parts by weight of a potassium titanate needle crystal, which has low viscosity and can be easily handled in a molding step.
    Type: Grant
    Filed: May 15, 1990
    Date of Patent: March 17, 1992
    Assignees: Sumitomo Bayer Urethane Co., Ltd., Toyota Jidosha Kabushiki Kaisha
    Inventors: Kanemitsu Kondo, Toshiaki Imokawa, Shinichi Murakami, Hideaki Nagayasu
  • Magnetic recording medium, a process for preparing a magnetic recording medium and a binder composition therefor
    Patent number: 4686145
    Abstract: A novel magnetic recording medium consisting of a base material, magnetic particles and a specific polyurethane-based binder containing incorporated sulphonate groups, a process for preparing such a magnetic recording medium which comprises coating a base material with a coating material comprising (i) an organic solvent, (ii) a polyurethane binder containing chemically incorporated sulphonate groups and (iii) magnetic particles and the most preferred binder composition therefor comprising a hexandiol-(1,6)-polycarbonate-based polyurethane.
    Type: Grant
    Filed: February 19, 1986
    Date of Patent: August 11, 1987
    Assignee: Sumitomo Bayer Urethane Co., Ltd.
    Inventors: Masaru Honda, Takanori Chiba, Toshiaki Imokawa, Yoshito Harada, Katsumi Nagayasu