Patents by Inventor Toshitaka Yamagata

Toshitaka Yamagata 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: 11492299
    Abstract: A nitride-based ceramics resin composite body having thermal conductivity, electrical insulation, and adhesion to adherends equal to conventional products, and having improved heat resistance reliability during the reflow process, and a thermal conductive insulating adhesive sheet using the same are provided. A nitride-based ceramics resin composite body in which a thermosetting resin composition is impregnated in a porous nitride-based ceramics sintered body is provided. The thermosetting resin composition includes a specific epoxy resin and a bismaleimide triazine resin, and a water absorption of the thermosetting resin composition in a completely cured state measured in accordance with method A in JIS K7209 (2000) is 1% by mass or less.
    Type: Grant
    Filed: December 5, 2018
    Date of Patent: November 8, 2022
    Assignee: DENKA COMPANY LIMITED
    Inventors: Yoshitaka Minakata, Eri Sasaki, Toshitaka Yamagata, Saori Inoue, Ryo Yoshimatu, Ryuji Koga
  • Patent number: 11034623
    Abstract: A thermal conductive member includes: first and second surface layers including an insulating material A, and an intermediate layer including an insulating material B. The insulating material A includes a first boron nitride sintered body having an orientation degree of hexagonal boron nitride primary particles of 0.6 to 1.4, and a first heat curable resin composition impregnating in the first boron nitride sintered body. The insulating material B includes a second boron nitride sintered body having an orientation degree of hexagonal boron nitride primary particles of 0.01 to 0.05, and a second heat curable resin composition impregnating in the second boron nitride sintered body.
    Type: Grant
    Filed: March 28, 2018
    Date of Patent: June 15, 2021
    Assignee: DENKA COMPANY LIMITED
    Inventors: Saori Inoue, Toshitaka Yamagata, Yoshitaka Minakata, Ryo Yoshimatsu, Ryuji Koga
  • Publication number: 20210032171
    Abstract: A nitride-based ceramics resin composite body having thermal conductivity, electrical insulation, and adhesion to adherends equal to conventional products, and having improved heat resistance reliability during the reflow process, and a thermal conductive insulating adhesive sheet using the same are provided. A nitride-based ceramics resin composite body in which a thermosetting resin composition is impregnated in a porous nitride-based ceramics sintered body is provided. The thermosetting resin composition includes a specific epoxy resin and a bismaleimide triazine resin, and a water absorption of the thermosetting resin composition in a completely cured state measured in accordance with method A in JIS K7209 (2000) is 1% by mass or less.
    Type: Application
    Filed: December 5, 2018
    Publication date: February 4, 2021
    Applicant: DENKA COMPANY LIMITED
    Inventors: Yoshitaka MINAKATA, Eri SASAKI, Toshitaka YAMAGATA, Saori INOUE, Ryo YOSHIMATU, Ryuji KOGA
  • Publication number: 20200406586
    Abstract: A ceramic-metal temporary bonding body to inhibit breakage and degradation of a ceramic resin composite having low strength includes: a ceramic resin composite in which a non-oxide ceramic sintered body is impregnated with a thermosetting resin composition having cyanate groups in such a manner that a degree of cure calculated by differential scanning calorimetry is 5.0% or more and 70% or less; and a metal plate temporarily bonded to at least one surface of the ceramic resin composite. A shear bond strength between the ceramic resin composite and the metal plate is 0.1 MPa or more and 1.0 MPa or less.
    Type: Application
    Filed: March 6, 2019
    Publication date: December 31, 2020
    Applicant: DENKA COMPANY LIMITED
    Inventors: Yoshitaka MINAKATA, Toshitaka YAMAGATA, Saori INOUE, Ryo YOSHIMATU, Ryuji KOGA
  • Patent number: 10615096
    Abstract: Provided is a heat dissipation structure for an electric circuit device excellent in mass-productivity and heat radiation performance. A heat dissipation structure for an electric circuit device, the structure including a layered structure comprising: a heatsink exposed on the electric circuit device; a thermal conductive member; and a cooler, wherein the thermal conductive member is a ceramic-resin composite in which a resin composition is impregnated in a ceramic sintered body, the ceramic sintered body comprising ceramic primary particles integrated into a three-dimensional structure, and wherein the thermal conductive member is arranged such that the thermal conductive member directly contacts with at least one of the heatsink and the cooler.
    Type: Grant
    Filed: August 2, 2017
    Date of Patent: April 7, 2020
    Assignee: DENKA COMPANY LIMITED
    Inventors: Toshitaka Yamagata, Saori Inoue, Hideki Hirotsuru, Ryoh Yoshimatu, Ryuji Koga
  • Publication number: 20200031723
    Abstract: A thermal conductive member includes: first and second surface layers including an insulating material A, and an intermediate layer including an insulating material B. The insulating material A includes a first boron nitride sintered body having an orientation degree of hexagonal boron nitride primary particles of 0.6 to 1.4, and a first heat curable resin composition impregnating in the first boron nitride sintered body. The insulating material B includes a second boron nitride sintered body having an orientation degree of hexagonal boron nitride primary particles of 0.01 to 0.05, and a second heat curable resin composition impregnating in the second boron nitride sintered body.
    Type: Application
    Filed: March 28, 2018
    Publication date: January 30, 2020
    Applicant: DENKA COMPANY LIMITED
    Inventors: Saori INOUE, Toshitaka YAMAGATA, Yoshitaka MINAKATA, Ryo YOSHIMATSU, Ryuji KOGA
  • Publication number: 20190189534
    Abstract: Provided is a heat dissipation structure for an electric circuit device excellent in mass-productivity and heat radiation performance. A heat dissipation structure for an electric circuit device, the structure including a layered structure comprising: a heatsink exposed on the electric circuit device; a thermal conductive member; and a cooler, wherein the thermal conductive member is a ceramic-resin composite in which a resin composition is impregnated in a ceramic sintered body, the ceramic sintered body comprising ceramic primary particles integrated into a three-dimensional structure, and wherein the thermal conductive member is arranged such that the thermal conductive member directly contacts with at least one of the heatsink and the cooler.
    Type: Application
    Filed: August 2, 2017
    Publication date: June 20, 2019
    Applicant: Denka Company Limited
    Inventors: Toshitaka YAMAGATA, Saori INOUE, Hideki HIROTSURU, Ryoh YOSHIMATU, Ryuji KOGA
  • Patent number: 9497857
    Abstract: An object of the present invention is to provide an insulating sheet superior in heat dissipation efficiency, heat resistance, insulation efficiency and moldability. Provided is a sheet-shaped insulating sheet of a resin composition containing an epoxy resin, a curing agent and an inorganic filler, wherein one or both of the epoxy resin and the curing agent have a naphthalene structure, the inorganic filler contains hexagonal boron nitride, and the inorganic filler is contained in an amount of 70 to 85 vol % in the entire resin composition. It is possible to increase the filling efficiency of an inorganic filler in the insulating sheet by using an epoxy resin and/or a curing agent having a naphthalene structure, which are favorably compatible with the hexagonal boron nitride contained in the inorganic filler.
    Type: Grant
    Filed: September 13, 2010
    Date of Patent: November 15, 2016
    Assignee: Denka Company Limited
    Inventors: Kenji Miyata, Toshitaka Yamagata
  • Patent number: 8921458
    Abstract: To provide a resin composition having excellent thermal conductivity and excellent insulation reliability, a molded object, a substrate material, and a circuit board. [Solution] Provided is a resin composition which comprises an epoxy resin, a hardener, and an inorganic filler, wherein the epoxy resin and/or the hardener has a naphthalene structure, the inorganic filler comprises hexagonal boron nitride, and the inorganic filler accounts for 50-85 vol. % of the whole resin composition. Since a naphthalene structure, which imparts the satisfactory ability to wet the hexagonal boron nitride included in the inorganic filler, has been introduced into the epoxy resin and/or the hardener to heighten the inorganic-filler loading characteristics, this resin composition attains excellent heat dissipation properties, heat resistance, insulating properties, etc.
    Type: Grant
    Filed: August 26, 2010
    Date of Patent: December 30, 2014
    Assignee: Denki Kagaku Kogyo Kabushiki Kaisha
    Inventors: Kenji Miyata, Toshitaka Yamagata
  • Publication number: 20130248755
    Abstract: Provided is a high durability thermally conductive composite containing 0.5-10 volume % of a high molecular weight silicone with vinyl groups on both ends with viscosity at 25 DEG C. of 10000-15000 Pa·s, 1-10 volume % of an alkylalkoxysilane, and 40-65 volume % of an inorganic filler with the remainder being an addition-reacting low molecular weight silicone with viscosity at 25 DEG C. of 0.2-0.5 Pa·s. Also provided is a grease characterized in containing 38-48 volume % of an addition-reacting low molecular weight silicone with viscosity at 25 DEG C. of 0.2-0.5 Pa·s, 2-8 volume % of a high molecular weight silicone with vinyl groups on both ends with viscosity at 25 DEG C. of 10000-15000 Pa·s, and 50-60 volume % of an inorganic filler. It is preferable that the alkylalkoxysilane is a triethoxysilane or trimethoxysilane wherein the number of carbons in the alkyl groups is six to ten.
    Type: Application
    Filed: May 13, 2013
    Publication date: September 26, 2013
    Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Takashi DOHMOTO, Kazuhiro OSHIMA, Toshitaka YAMAGATA
  • Publication number: 20130143981
    Abstract: To provide a resin composition having excellent thermal conductivity and excellent insulation reliability, a molded object, a substrate material, and a circuit board. [Solution] Provided is a resin composition which comprises an epoxy resin, a hardener, and an inorganic filler, wherein the epoxy resin and/or the hardener has a naphthalene structure, the inorganic filler comprises hexagonal boron nitride, and the inorganic filler accounts for 50-85 vol. % of the whole resin composition. Since a naphthalene structure, which imparts the satisfactory ability to wet the hexagonal boron nitride included in the inorganic filler, has been introduced into the epoxy resin and/or the hardener to heighten the inorganic-filler loading characteristics, this resin composition attains excellent heat dissipation properties, heat resistance, insulating properties, etc.
    Type: Application
    Filed: August 26, 2010
    Publication date: June 6, 2013
    Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Kenji Miyata, Toshitaka Yamagata
  • Publication number: 20120188730
    Abstract: An object of the present invention is to provide an insulating sheet superior in heat dissipation efficiency, heat resistance, insulation efficiency and moldability. Provided is a sheet-shaped insulating sheet of a resin composition containing an epoxy resin, a curing agent and an inorganic filler, wherein one or both of the epoxy resin and the curing agent have a naphthalene structure, the inorganic filler contains hexagonal boron nitride, and the inorganic filler is contained in an amount of 70 to 85 vol % in the entire resin composition. It is possible to increase the filling efficiency of an inorganic filler in the insulating sheet by using an epoxy resin and/or a curing agent having a naphthalene structure, which are favorably compatible with the hexagonal boron nitride contained in the inorganic filler.
    Type: Application
    Filed: September 13, 2010
    Publication date: July 26, 2012
    Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Kenji Miyata, Toshitaka Yamagata
  • Publication number: 20100048435
    Abstract: The present invention provides a grease showing low thermal resistance, which is not significantly deteriorated by a heat cycle, particularly, a grease suitable as a thermally conductive material for heat-generating electronic components. A grease containing one type or at least two types of thermally conductive material powder selected from the group consisting of a thermally conductive material (A), a thermally conductive material (B) and a thermally conductive material (C), wherein the particle size distribution of the thermally conductive material powder measured by a laser diffraction type particle size distribution method, has population peaks in the ranges of from 2.0 to 10 ?m, from 1.0 to 1.9 ?m and from 0.1 to 0.9 ?m, respectively, and the grease contains a base oil having a surface tension of from 25 to 40 dyn/cm at 25° C.
    Type: Application
    Filed: October 16, 2007
    Publication date: February 25, 2010
    Applicant: Denki Kagaku Kogyo Kabushiki Kaisha
    Inventors: Toshitaka Yamagata, Takuya Okada, Akira Ubukata
  • Patent number: 4539459
    Abstract: A wire-cut electrical discharge machine which effects an electrical discharges between a wire electrode and the workpiece. The wire-cut machine has a supply nozzle for supplying a machining fluid to an electrical discharge machining zone and a power-feed element for supplying pulse power to the wire electrode. The power-feed element contacting the wire electrode is provided inside the supply nozzle.
    Type: Grant
    Filed: May 18, 1983
    Date of Patent: September 3, 1985
    Assignee: Amada Company, Limited
    Inventor: Toshitaka Yamagata