Patents by Inventor Hiroharu Takeshima

Hiroharu Takeshima 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 producing poly(p-t-butoxystyrene)
    Patent number: 6423821
    Abstract: A method for producing poly(p-t-butoxystyrene), which comprises polymerizing p-t-butoxystyrene in a hydrocarbon type reaction solvent in the presence of a polymerization initiator, and, after termination of the polymerization reaction, conducting a separation of the hydrocarbon type reaction solvent layer containing poly(p-t-butoxystyrene) and the water layer in the presence of 1-50 parts by weight of a polar solvent per 100 parts by weight of the hydrocarbon type reaction solvent layer, wherein the separation efficiency, after termination of the polymerization reaction, of the hydrocarbon type reaction solvent layer containing poly(p-t-butoxystyrene) and the water or acidic water layer conspicuously improves.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: July 23, 2002
    Assignee: Sumitomo Chemical Company, Ltd.
    Inventors: Takanori Okahashi, Hiroharu Takeshima, Seigo Ito
  • Method for producing poly (p-t-butoxystyrene)
    Patent number: 6395854
    Abstract: Disclosed is a method for producing poly(p-t-butoxystyrene) by polymerizing p-t-butoxystyrene using an organometallic compound as a polymerization initiator, wherein a mixed solvent comprising a hydrocarbon solvent and a diether of (poly)alkylene glycol is used as a solvent, and this method can provide the desired poly(p-t-butoxystyrene) efficiently and readily under relatively mild conditions.
    Type: Grant
    Filed: December 7, 1999
    Date of Patent: May 28, 2002
    Assignee: Sumitomo Chemical Company, Limited
    Inventor: Hiroharu Takeshima
  • Method for producing poly(p-t-butoxystyrene)
    Publication number: 20020026023
    Abstract: A method for producing poly(p-t-butoxystyrene), which comprise polymerizing p-t-butoxystyrene in a hydrocarbon type reaction solvent in the presence of a polymerization initiator, and, after termination of the polymerization reaction, conducting a separation of the hydrocarbon type reaction solvent layer containing poly(p-t-butoxystyrene) and the water layer in the presence of 1-50 parts by weight of a polar solvent per 100 parts by weight of the hydrocarbon type reaction solvent layer, wherein the separation efficiency, after termination of the polymerization reaction, of the hydrocarbon type reaction solvent layer containing poly(p-t-butoxystyrene) and the water or acidic water layer conspicuously improves.
    Type: Application
    Filed: August 23, 2001
    Publication date: February 28, 2002
    Inventors: Takanori Okahashi, Hiroharu Takeshima, Seigo Ito
  • Method for producing poly(p-t-butoxystyrene)
    Patent number: 6291604
    Abstract: A method for producing poly(p-t-butoxystyrene) by a polymerization reaction of p-t-butoxystyrene characterized in that p-t-butoxystyrene or a solution thereof is added little by little to a mixture of the reaction solvent and the polymerization initiator, and water content of the p-t-butoxystyrene or a solution thereof is in a range of 5-70 ppm, and according to the method, poly(p-t-butoxystyrene) having narrow molecular weight distribution can be produced securely, with easy reaction temperature control.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: September 18, 2001
    Assignee: Sumitomo Chemical Company Limited
    Inventor: Hiroharu Takeshima