Patents by Inventor Hitoshi Ohba

Hitoshi Ohba 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 the polymerization of vinyl chloride monomer in an aqueous medium
    Patent number: 4694053
    Abstract: The invention provides an improvement in the suspension polymerization of vinyl chloride in an aqueous medium in the presence of a monomer-soluble polymerization initiator, according to which the amount of polymer scale deposition on the reactor walls can be greatly decreased. The improvement comprises admixing the aqueous polymerization medium with (a) a water-soluble crosslinked copolymer of an unsaturated carboxylic acid monomer, e.g. acrylic acid, and a crosslinking monomer such as di(methyl)allyl ether of diethyleneglycol and (b) a non-ionic surface active agent in combination.
    Type: Grant
    Filed: June 25, 1985
    Date of Patent: September 15, 1987
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Kenichi Itoh, Genji Noguki, Motoaki Tanaka, Hitoshi Ohba
  • Process for producing aqueous suspension containing organic azo compound as polymerization initiator
    Patent number: 4500649
    Abstract: A stable aqueous suspension containing an organic azo compound as polymerization initiator in fine particles, containing substantially no organic solvent and containing no foam which damages dispersing stability of the aqueous suspension and retards polymerization rate can be formed by dissolving an organic azo compound in an organic solvent, emulsifying the resulting solution by adding water and a dispersing agent A and a dispersing agent B thereto with stirring, and removing the organic solvent from the emulsified liquid preferably under reduced pressure.
    Type: Grant
    Filed: October 12, 1982
    Date of Patent: February 19, 1985
    Assignee: Wako Pure Chemical Industries, Ltd.
    Inventors: Motoaki Tanaka, Takanori Toyama, Hitoshi Ohba, Osamu Yamaguchi
  • Method for the polymerization of vinyl chloride monomer in an aqeous medium
    Patent number: RE33284
    Abstract: The invention provides an improvement in the suspension polymerization of vinyl chloride in an aqueous medium in the presence of a monomer-soluble polymerization initiator, according to which the amount of polymer scale deposition on the reactor walls can be greatly decreased. The improvement comprises admixing the aqueous polymerization medium with (a) a water-soluble crosslinked copolymer of an unsaturated carboxylic acid monomer, e.g. acrylic acid, and a crosslinking monomer such as di(methyl)allyl ether of diethyleneglycol and (b) a non-ionic surface active agent in combination.
    Type: Grant
    Filed: November 30, 1987
    Date of Patent: July 31, 1990
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Kenichi Itoh, Genji Noguki, Motoaki Tanaka, Hitoshi Ohba, Masahiko Watase