Patents by Inventor Hiroharu Shirota

Hiroharu Shirota 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).

  • Processes for producing polycarbonate polyols
    Patent number: 4891421
    Abstract: A process for producing a polycarbonate polyol by ester-interchange reaction of a dialkyl, diaryl or alkylene carbonate and a polyhydroxy compound, wherein the dialkyl, diaryl or alkylene carbonate is purified by adsorption treatment with an adsorbent prior to use in the reaction. A process for producing a polycarbonate polyol which comprises ester-interchange reaction of a dialkyl or diaryl carbonate and a polyhydroxy compound in the presence of a catalyst, wherein the proportion of the polyhydroxy compound to the dialkyl or diaryl carbonate is 1.01 to 1.30 times its stoichiometrical amount, and the amount of the catalyst is 0.0001 to 0.5% by weight, calculated as metal, based on the dialkyl or diaryl carbonate. Also provided is a process for producing a polycarbonate polyol by ester-interchange reaction of a dialkyl, diaryl or alkylene carbonate and a polyhydroxy compound in the presence of a catalyst in an amount, as metal, of 0.0001 to 0.
    Type: Grant
    Filed: June 22, 1988
    Date of Patent: January 2, 1990
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Katsuhide Nishimura, Motoyasu Kunugiza, Hiroharu Shirota, Hideyuki Ishizu