Patents by Inventor Yoshinao Doi

Yoshinao Doi 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).

  • Patent number: 5022990
    Abstract: A porous membrane comprising a polyvinylidene fluoride resin and having a uniform, three-dimensional, network pore structure. The membrane has excellent chemical resistance, excellent filtering characteristics and excellent mechanical properties. The porous membrane can be produced by blending a polyvinylidene fluoride resin, an organic liquid and a powdery hydrophobic silica, subjecting the resultant blend to melt-molding to form a membrane, and extracting the organic liquid and the hydrophobic silica from the melt-molded membrane.
    Type: Grant
    Filed: January 10, 1990
    Date of Patent: June 11, 1991
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Yoshinao Doi, Haruo Matsumura
  • Patent number: 4409339
    Abstract: A sulfonated polyolefin porous membrane containing sulfonic groups in an amount, in terms of exchange capacity, of 0.05 to 1 milliequivalent per gram of the sulfonated polyolefin and having a porosity of 30 to 85% and an average pore diameter of 0.05 to 1.mu. has been found to be excellent in water permeability, removal capability, water-permeability retention, mechanical strength and elongation, etc. The porous membrane of the present invention may advantageously be employed as a fine microfilter or the like. The porous membrane of the present invention may be easily prepared by treating with a sulfonating agent a polyolefin porous membrane preferably containing an inorganic filler which is subsequently extracted from the membrane.
    Type: Grant
    Filed: October 6, 1980
    Date of Patent: October 11, 1983
    Assignee: Asahi Kasei Kogyo
    Inventors: Kazuo Matsuda, Mitsuo Kohno, Yoshinao Doi
  • Patent number: 4335193
    Abstract: This invention is directed to a microporous film comprising a 40 to 90 volume percent polyolefin having a number average molecular weight of 15,000 or more and a weight average molecular weight of less than 300,000 and a 10 to 60 volume percent inorganic filler and having a void space rate or porosity of 30 to 75 volume percent based on the volume of the film. The microporous film of such specific composition and structure has a desired wettability and a much reduced electrical resistance. Said resistance being as low as 0.0006 .OMEGA.dm.sup.2 /sheet. Said film has sufficient flexibility and mechanical strength to make it useful in wide variety of applications, especially as separators in batteries or electrolytical apparatuses etc.
    Type: Grant
    Filed: February 28, 1979
    Date of Patent: June 15, 1982
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Yoshinao Doi, Shigeo Kaneko, Takeo Hanamura, Osamu Fujii, Katsumi Yoshitake, Tetsuhiko Hirata, Yasuhiro Tanabe
  • Patent number: 4331622
    Abstract: A microporous film which comprises a matrix comprising 40 to 90 volume percent of a polyolefin having a number average molecular weight of 15,000 or more and 10 to 60 volume percent of an inorganic filler, said matrix having therein void spaces at a rate of 30 to 75 volume percent based on the volume of the film; and 2 to 20 weight percent, based on the total weight of the polyolefin and the inorganic filler, of an organic substance which is substantially insoluble in and inert to sulfuric acid and has a solubility parameter ranging from 7.3 inclusive to 8.4 exclusive; said organic substance, in its majority, adhering to the overall surface of the film including the outer surfaces of the film and the surfaces of the polyolefin walls defining said void spaces in cooperation with said inorganic filler.
    Type: Grant
    Filed: January 14, 1980
    Date of Patent: May 25, 1982
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Yoshinao Doi, Osamu Fujii, Shigeo Kaneko, Takeo Hanamura
  • Patent number: 4229297
    Abstract: A specific porous membrane is found to be extremely useful for permeation-separation of an oil from an oil-containing emulsion. By contacting a stable oil-containing emulsion of either water-in-oil type or oil-in-water type with the surface of a specific porous membrane having at its surface a critical surface tension of less than 35 dynes/cm to not less than 20 dynes/cm and having an average pore diameter of 0.03 .mu.m to 5 .mu.m, a pore radius distribution of not more than 1.5 and a porosity of 1 to 85%, only the oil can be permeation-separated, without permeation of the liquid immiscible with the oil, with high selectivity and high oil permeation.
    Type: Grant
    Filed: January 9, 1979
    Date of Patent: October 21, 1980
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Takashi Nohmi, Takao Yamada, Yoshinao Doi
  • Patent number: 4210709
    Abstract: A microporous film which comprises a matrix comprising 40 to 90 volume percent of a polyolefin having a number average molecular weight of 15,000 or more and 10 to 60 volume percent of an inorganic filler, said matrix having therein void spaces at a rate of 30 to 75 volume percent based on the volume of the film; and 2 to 20 weight percent, based on the total weight of the polyolefin and the inorganic filler, of an organic substance which is substantially insoluble in and inert to sulfuric acid and has a solubility parameter ranging from 7.3 inclusive to 8.4 exclusive; said organic substance, in its majority, adhering to the overall surface of the film including the outer surfaces of the film and the surfaces of the polyolefin walls defining said void spaces in cooperation with said inorganic filler.
    Type: Grant
    Filed: August 1, 1978
    Date of Patent: July 1, 1980
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Yoshinao Doi, Osamu Fugii, Shigeo Kaneko, Takeo Hanamura
  • Patent number: 4190707
    Abstract: An alkaline battery separator made of a porous film which consists substantially of a polyolefin having a weight average molecular weight of less than 300,000 and a number average molecular weight of 15,000 or more and which has a thickness of 0.025 to 1 mm, a porosity of 50 to 80%, an average pore diameter of 0.05 to 0.5.mu. and an average ratio of the larger dimension to the smaller dimension of the pore opening of not more than 2. The alkaline battery separator has not only an extremely low electrical resistance and a high alkali resistance but also a transmission-inhibitive ability for the active materials of battery and is excellent in mechanical strength and flexibility. It does not show appreciable shrinkage by heat. For producing such an alkaline battery separator, 10 to 50 volume percent of a polyolefin, 7 to 42 volume percent of an inorganic filler and 30 to 75 volume percent of an organic liquid having a solubility parameter of from 8.6 to 9.
    Type: Grant
    Filed: October 3, 1978
    Date of Patent: February 26, 1980
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Yoshinao Doi, Mitsuo Kohno, Katsumi Yoshitake