Patents by Inventor Taku Okano

Taku Okano 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: 11413685
    Abstract: A silver powder mixture that is suitable for forming a conductive film on a surface of a member having stretchability, a method for producing the same, and a conductive paste using the silver powder mixture is provided. A silver powder mixture containing filamentous silver powder including spherical and filamentous parts and flaky silver powder having an average particle diameter of 1 ?m or more and 50 ?m or less and an aspect ratio, which is defined by a ratio of an average long diameter and an average thickness, of 1.5 or more is obtained by adding one kind or two or more kinds of a salt of copper and aluminum and ethylenediaminetetraacetic acid to a silver nitrate aqueous solution, for 60 seconds or more, and then adding a reducing agent containing one kind or two or more kinds of L-ascorbic acid, erythorbic acid, and salts thereof.
    Type: Grant
    Filed: September 19, 2018
    Date of Patent: August 16, 2022
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Genta Sasaki, Taku Okano, Yoshio Moteki, Yu Saito
  • Patent number: 11081253
    Abstract: There is provided an inexpensive silver particle dispersing solution being usable as a slurry for ink jet, a method for producing the same, and a method for producing a conductive film using the silver particle dispersing solution. In a silver particle dispersing solution containing a silver powder and a solvent, the silver powder has an average primary particle diameter (DSEM) of 0.15 to 0.5 ?m, and the ratio (D50/DSEM) of a particle diameter (D50), which corresponds to 50% of accumulation in volume-based cumulative distribution of the silver powder, to the average primary particle diameter (DSEM) is not less than 1.7, the silver powder having a fatty acid adhered to the surface thereof, and the solvent containing a monohydric higher alcohol having a carbon number of 6 to 12, butyl carbitol or butyl carbitol acetate as the main component thereof.
    Type: Grant
    Filed: June 11, 2017
    Date of Patent: August 3, 2021
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Taku Okano, Noriaki Nogami
  • Publication number: 20210060655
    Abstract: A silver powder mixture that is suitable for forming a conductive film on a surface of a member having stretchability, a method for producing the same, and a conductive paste using the silver powder mixture is provided. A silver powder mixture containing filamentous silver powder including spherical and filamentous parts and flaky silver powder having an average particle diameter of 1 ?m or more and 50 ?m or less and an aspect ratio, which is defined by a ratio of an average long diameter and an average thickness, of 1.5 or more is obtained by adding one kind or two or more kinds of a salt of copper and aluminum and ethylenediaminetetraacetic acid to a silver nitrate aqueous solution, for 60 seconds or more, and then adding a reducing agent containing one kind or two or more kinds of Lascorbic acid, erythorbic acid, and salts thereof.
    Type: Application
    Filed: September 19, 2018
    Publication date: March 4, 2021
    Inventors: Genta SASAKI, Taku OKANO, Yoshio MOTEKI, Yu SAITO
  • Patent number: 10773961
    Abstract: To provide a silver-coated graphite mixed powder including: silver-coated graphite particles each including a graphite particle and silver coated on a surface of the graphite particle, where when a solution obtained by dissolving the silver-coated graphite mixed powder in nitric acid is analyzed through inductively coupled plasma (ICP) emission spectrometry, an amount of silver is 5% by mass or more but 90% by mass or less, an amount of tin is 0.01% by mass or more but 5% by mass or less, and an amount of zinc is 0.002% by mass or more but 1% by mass or less.
    Type: Grant
    Filed: December 6, 2016
    Date of Patent: September 15, 2020
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kairi Otani, Noriaki Nogami, Yoshio Moteki, Taku Okano
  • Publication number: 20190259510
    Abstract: There is provided an inexpensive silver particle dispersing solution being usable as a slurry for ink jet, a method for producing the same, and a method for producing a conductive film using the silver particle dispersing solution. In a silver particle dispersing solution containing a silver powder and a solvent, the silver powder has an average primary particle diameter (DSEM) of 0.15 to 0.5 ?m, and the ratio (D50/DSEM) of a particle diameter (D50), which corresponds to 50% of accumulation in volume-based cumulative distribution of the silver powder, to the average primary particle diameter (DSEM) is not less than 1.7, the silver powder having a fatty acid adhered to the surface thereof, and the solvent containing a monohydric higher alcohol having a carbon number of 6 to 12, butyl carbitol or butyl carbitol acetate as the main component thereof.
    Type: Application
    Filed: June 11, 2017
    Publication date: August 22, 2019
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Taku Okano, Noriaki Nogami
  • Publication number: 20180362348
    Abstract: To provide a silver-coated graphite mixed powder including: silver-coated graphite particles each including a graphite particle and silver coated on a surface of the graphite particle, where when a solution obtained by dissolving the silver-coated graphite mixed powder in nitric acid is analyzed through inductively coupled plasma (ICP) emission spectrometry, an amount of silver is 5% by mass or more but 90% by mass or less, an amount of tin is 0.01% by mass or more but 5% by mass or less, and an amount of zinc is 0.002% by mass or more but 1% by mass or less.
    Type: Application
    Filed: December 6, 2016
    Publication date: December 20, 2018
    Inventors: Kairi Otani, Noriaki Nogami, Yoshio Moteki, Taku Okano
  • Publication number: 20180308603
    Abstract: To provide a conductive paste including: a filler containing a silver powder and a graphite powder; a polymer; and a solvent, where a 1%-weight-reduction starting temperature of the graphite powder, which is determined through a thermogravimetry-differential thermal analysis method, is 300° C. or more but 640° C. or less.
    Type: Application
    Filed: September 23, 2016
    Publication date: October 25, 2018
    Inventors: Taku Okano, Noriaki Nogami, Yoshio Moteki
  • Patent number: 8916068
    Abstract: Provided is a silver micropowder coated with a protective material and capable of more drastically reducing the sintering temperature than before. The silver micropowder comprises silver particles processed to adsorb hexylamine (C6H13—NH2) on the surfaces thereof and having a mean particle diameter DTEM of from 3 to 20 nm or an X-ray crystal particle diameter DX of from 1 to 20 nm. The silver micropowder has the property of forming a conductive film having a specific resistivity of not more than 25 ??·cm when it is mixed with an organic medium to prepare a silver coating material and when a coating film formed of it is fired in air at 120° C. Even when fired at 100° C., it may form a conductive film having a specific resistivity of not more than 25 ??·cm.
    Type: Grant
    Filed: December 25, 2008
    Date of Patent: December 23, 2014
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Kimitaka Sato, Taku Okano, Taro Nakanoya
  • Publication number: 20120045573
    Abstract: Provided is a silver conductive film, a thin film of silver comprising a sintered layer of silver particles having a mean particle size DTEM of at most 100 nm. Its specific resistance is at most 5 ??·cm, the ratio of the voids in the sintered layer is at most 3/?m2, and the film has a texture structure with a surface roughness Ra of from 10 to 100 nm. The silver conductive film having such a texture structure may be produced according to a production process comprising a step of applying a silver particle dispersion of silver particles having a mean particle size DTEM of at most 100 nm dispersed in a non-polar or poorly-polar liquid organic medium having a boiling point of from 60 to 300° C., onto a substrate to form a coating film thereon, and thereafter baking the coating film.
    Type: Application
    Filed: October 14, 2011
    Publication date: February 23, 2012
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kimitaka SATO, Yutaka HISAEDA, Taku OKANO, Kozo Ogi
  • Patent number: 7981326
    Abstract: A silver fine powder comprising silver particles with an average particle diameter of 20 nm or less and having an organic protective material on the surface thereof, wherein the proportion of the organic protective material present is 0.05 to 25% by mass based on the total mass of the silver particles and the organic protective material. An amine compound having a molecular weight of 100 to 1,000 is preferably used as the organic protective material, and that having one or more unsaturated bond in one molecule is particularly preferred. This silver fine powder has, for example, a crystallite diameter in (111) crystal plane of silver particle of 20 nm or less. The present invention further provides an ink comprising particles of the silver fine powder dispersed in an organic solvent in the silver concentration of 10% by mass or more, the ink having a viscosity of 50 mPa·s or less.
    Type: Grant
    Filed: January 8, 2008
    Date of Patent: July 19, 2011
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Kimitaka Sato, Taku Okano
  • Publication number: 20100283013
    Abstract: Provided is a silver micropowder coated with a protective material and capable of more drastically reducing the sintering temperature than before. The silver micropowder comprises silver particles processed to adsorb hexylamine (C6H13—NH2) on the surfaces thereof and having a mean particle diameter DTEM of from 3 to 20 nm or an X-ray crystal particle diameter DX of from 1 to 20 nm. The silver micropowder has the property of forming a conductive film having a specific resistivity of not more than 25 ??·cm when it is mixed with an organic medium to prepare a silver coating material and when a coating film formed of it is fired in air at 120° C. Even when fired at 100° C., it may form a conductive film having a specific resistivity of not more than 25 ??·cm.
    Type: Application
    Filed: December 25, 2008
    Publication date: November 11, 2010
    Inventors: Kimitaka Sato, Taku Okano, Taro Nakanoya
  • Publication number: 20100006002
    Abstract: A silver fine powder comprising silver particles with an average particle diameter of 20 nm or less and having an organic protective material on the surface thereof, wherein the proportion of the organic protective material present is 0.05 to 25% by mass based on the total mass of the silver particles and the organic protective material. An amine compound having a molecular weight of 100 to 1,000 is preferably used as the organic protective material, and that having one or more unsaturated bond in one molecule is particularly preferred. This silver fine powder has, for example, a crystallite diameter in (111) crystal plane of silver particle of 20 nm or less. The present invention further provides an ink comprising particles of the silver fine powder dispersed in an organic solvent in the silver concentration of 10% by mass or more, the ink having a viscosity of 50 mPa·s or less.
    Type: Application
    Filed: January 8, 2008
    Publication date: January 14, 2010
    Inventors: Kimitaka Sato, Taku Okano
  • Publication number: 20090236567
    Abstract: A powder of silver particles having an organic protective film, which has a broad particle size distribution of such that the CV value, as computed according to the following formula (1) in which the particle diameter is determined by TEM (transmission electromicroscopy), is at least 40%. The organic protective film comprises, for example, a fatty acid (oleic acid, etc.) having a molecular weight of from 100 to 1000 and an amine compound having a molecular weight of from 100 to 1000, and at least any one of the fatty acid and the amine compound has at least one unsaturated bond in one molecule.
    Type: Application
    Filed: September 11, 2007
    Publication date: September 24, 2009
    Inventors: Kozo Ogi, Taku Okano
  • Publication number: 20090053469
    Abstract: Provided is a silver conductive film, a thin film of silver comprising a sintered layer of silver particles having a mean particle size DTEM of at most 100 nm. Its specific resistance is at most 5 ??·cm, the ratio of the voids in the sintered layer is at most 3/?m2, and the film has a texture structure with a surface roughness Ra of from 10 to 100 nm. The silver conductive film having such a texture structure may be produced according to a production process comprising a step of applying a silver particle dispersion of silver particles having a mean particle size DTEM of at most 100 nm dispersed in a non-polar or poorly-polar liquid organic medium having a boiling point of from 60 to 300° C., onto a substrate to form a coating film thereon, and thereafter baking the coating film.
    Type: Application
    Filed: January 9, 2007
    Publication date: February 26, 2009
    Inventors: Kimitaka Sato, Yutaka Hisaeda, Taku Okano, Kozo Ogi