Patents by Inventor Yasunari Maekawa

Yasunari Maekawa 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).

  • Publication number: 20120148939
    Abstract: An anion exchange membrane includes a quaternary ammonium salt group in which two methyl groups, and one alkyl group having 3 to 8 carbon atoms are bonded to a nitrogen atom.
    Type: Application
    Filed: November 3, 2011
    Publication date: June 14, 2012
    Applicant: JAPAN ATOMIC ENERGY AGENCY
    Inventors: Kazuya Yamamoto, Koji Yamada, Susumu Yamaguchi, Hirohisa Tanaka, Masaharu Asano, Tetsuya Yamaki, Hiroshi Koshikawa, Yasunari Maekawa, Warapon Sinananwanich
  • Patent number: 7993793
    Abstract: By performing photograft polymerization of functional monomers such that grafted chains will be introduced from the surface of a polymer base film into its interior without deteriorating its inherent characteristics and also by creating a multiplex crosslinked structure between the grafted chains and the base film under such conditions as to cause preferential radiation-induced crosslinking reaction, there is produced a polymer electrolyte membrane having high enough oxidation resistance and proton conductivity to be suitable for use in fuel cells.
    Type: Grant
    Filed: March 23, 2007
    Date of Patent: August 9, 2011
    Assignees: Japan Atomic Energy Agency, Nitto Denko Corporation
    Inventors: Masaru Yoshida, Masaharu Asano, Jinhua Chen, Yasunari Maekawa, Toshimitsu Tachibana, Yozo Nagai, Soji Nishiyama
  • Publication number: 20100216901
    Abstract: A method of producing an electrolyte membrane for use in a fuel cell, including: performing radiation-induced graft polymerization of a vinyl monomer having a nucleophilic functional group selected from an acylvinyl ether derivative, a styrene derivative, and a methacrylic acid derivative, with a polymer substrate having a fluorine-containing polymer, an olefin-containing polymer, or an aromatic polymer; deprotecting an ester bond of a graft chain on the polymer substrate introduced by the radiation-induced graft polymerization; and introducing an alkylethersulfonic acid structure into the nucleophilic functional group of the graft chain thus deprotected, by use of an electrophilic reagent selected from cyclic sulfonic acid ester and alkylhalide sulfonate.
    Type: Application
    Filed: January 26, 2010
    Publication date: August 26, 2010
    Applicants: JAPAN ATOMIC ENERGY AGENCY, KANAGAWA UNIVERSITY
    Inventors: Yasunari Maekawa, Kazuyuki Enomoto, Nobuhiro Kihara
  • Publication number: 20100190875
    Abstract: An aromatic polymer film substrate, or a grafted aromatic polymer film substrate having a monomer introduced therein as graft chains is irradiated with ionizing radiation to impart a crosslinked structure. The aromatic polymer film substrate or the grafted aromatic polymer film substrate, provided with the crosslinked structure, is directly sulfonated to obtain a crosslinked aromatic polymer electrolyte membrane. The crosslinked aromatic polymer electrolyte membrane has low water uptake, high proton conductivity, low methanol permeability, high chemical stability, and excellent mechanical characteristics.
    Type: Application
    Filed: April 1, 2010
    Publication date: July 29, 2010
    Applicant: JAPAN ATOMIC ENERGY AGENCY
    Inventors: Jinhua Chen, Yasunari Maekawa, Masaharu Asano, Masaru Yoshida
  • Patent number: 7714027
    Abstract: An aromatic polymer film substrate, or a grafted aromatic polymer film substrate having a monomer introduced therein as graft chains is irradiated with ionizing radiation to impart a crosslinked structure. The aromatic polymer film substrate or the grafted aromatic polymer film substrate, provided with the crosslinked structure, is directly sulfonated to obtain a crosslinked aromatic polymer electrolyte membrane. The crosslinked aromatic polymer electrolyte membrane has low water uptake, high proton conductivity, low methanol permeability, high chemical stability, and excellent mechanical characteristics. A method for producing the crosslinked aromatic polymer electrolyte membrane is also provided.
    Type: Grant
    Filed: January 31, 2008
    Date of Patent: May 11, 2010
    Assignee: Japan Atomic Energy Agency
    Inventors: Jinhua Chen, Yasunari Maekawa, Masaharu Asano, Masaru Yoshida
  • Publication number: 20100040927
    Abstract: An object is to provide an electrolyte membrane that maintains excellent cell characteristics for a long time under high temperature and low water retention, as this is the most important point in fuel cells. A process for producing a polymer electrolyte membrane for fuel cells is provided, which process comprises in sequence: forming graft molecular chains by graft-polymerization of a vinyl silane coupling agent on a polymer film substrate that has phenyl groups capable of holding sulfonic acid groups; introducing sulfonic acid groups into phenyl groups contained in the graft molecular chains; and hydrolyzing and condensing alkoxy groups contained in the graft molecular chains so that a silane crosslinked structure is introduced between the graft molecular chains. A polymer electrolyte membrane produced by the process is also provided.
    Type: Application
    Filed: September 5, 2007
    Publication date: February 18, 2010
    Inventors: Masaru Yoshida, Masaharu Asano, Jinhua Chen, Yasunari Maekawa, Toshimitsu Tachibana, Yozo Nagai, Soji Nishiyama
  • Publication number: 20090325027
    Abstract: Provision of, and a method for production of, a polymer electrolyte membrane, which is characterized by introducing a vinyl monomer into an aromatic polymer membrane substrate, typified by polyether ether ketone, polyether imide, or polysulfone, as graft chains by graft polymerization, and then chemically converting some of the graft chains or/and part of the aromatic polymer chain into sulfonic groups.
    Type: Application
    Filed: August 24, 2007
    Publication date: December 31, 2009
    Inventors: Yasunari Maekawa, Shin Hasegawa, Yasuyuki Suzuki
  • Publication number: 20090068534
    Abstract: A vinyl monomer is graft polymerized on an aromatic hydrocarbon-based polymer film substrate to introduce graft chains into the substrate and thereafter a functional monomer represented by the following formula and having sulfonic acid groups or functional groups capable of conversion to sulfonic acid groups is graft polymerized to introduce the sulfonic acid groups or the functional groups capable of conversion to sulfonic acid groups: where R is an aromatic ring or an aliphatic chain; X is (1) —OH, (2) —OLi, —ONa or —OK, (3) —F or —Cl, or (4) —OCnH2n+1 where n is an integer of 1 to 7. Since the graft chains obtained by graft polymerization of the vinyl monomer can also be utilized as scaffold polymers, the graft polymerizability of the functional monomer to the aromatic hydrocarbon-based polymer film substrate is sufficiently improved to enable the preparation of a polymer electrolyte membrane that excels not only in proton conductivity and mechanical strength but also in dimensional stability.
    Type: Application
    Filed: August 22, 2008
    Publication date: March 12, 2009
    Applicant: JAPAN ATOMIC ENERGY AGENCY
    Inventors: Jinhua Chen, Yasunari Maekawa, Masaharu Asano, Masaru Yoshida
  • Publication number: 20080312350
    Abstract: An aromatic polymer film substrate, or a grafted aromatic polymer film substrate having a monomer introduced therein as graft chains is irradiated with ionizing radiation to impart a crosslinked structure. The aromatic polymer film substrate or the grafted aromatic polymer film substrate, provided with the crosslinked structure, is directly sulfonated to obtain a crosslinked aromatic polymer electrolyte membrane. The crosslinked aromatic polymer electrolyte membrane has low water uptake, high proton conductivity, low methanol permeability, high chemical stability, and excellent mechanical characteristics. A method for producing the crosslinked aromatic polymer electrolyte membrane is also provided.
    Type: Application
    Filed: January 31, 2008
    Publication date: December 18, 2008
    Applicant: JAPAN ATOMIC ENERGY AGENCY
    Inventors: Jinhua Chen, Yasunari Maekawa, Masaharu Asano, Masaru Yoshida
  • Publication number: 20080199756
    Abstract: Polymer electrolyte membranes for use in fuel cells are produced by first graft polymerizing acrylic acid derivatives or vinylketone derivatives as monomers on polymer substrates and by then performing selective conversion to a sulfonic acid group of hydrogen atoms on the carbon atom adjacent to the carbonyl in the ketone or carboxyl group on the graft chains.
    Type: Application
    Filed: February 8, 2008
    Publication date: August 21, 2008
    Applicant: JAPAN ATOMIC ENERGY AGENCY
    Inventors: Shuichi Takahashi, Yasunari Maekawa, Shin Hasegawa
  • Publication number: 20070224480
    Abstract: By performing photograft polymerization of functional monomers such that grafted chains will be introduced from the surface of a polymer base film into its interior without deteriorating its inherent characteristics and also by creating a multiplex crosslinked structure between the grafted chains and the base film under such conditions as to cause preferential radiation-induced crosslinking reaction, there is produced a polymer electrolyte membrane having high enough oxidation resistance and proton conductivity to be suitable for use in fuel cells.
    Type: Application
    Filed: March 23, 2007
    Publication date: September 27, 2007
    Applicants: JAPAN ATOMIC ENERGY AGENCY, NITTO DENKO CORPORATION
    Inventors: Masaru Yoshida, Masaharu Asano, Jinhun Chen, Yasunari Maekawa, Toshimitsu Tachibana, Yozo Nagai, Soji Nishiyama
  • Patent number: 6836305
    Abstract: A reflection-type liquid crystal display device, having a pair of substrates, at least one of which is transparent, a liquid crystal layer sandwiched between the pair of substrates, a light reflector section provided between the liquid crystal layer and one of the pair of substrates, and a polymeric medium layer with fine silver particles precipitated on the surface, as formed at the light reflector section. The reflection-type liquid crystal display is produced by the steps of: applying a mixture containing monovalent silver and a photosensitive polymeric medium; exposing the mixture to light, thereby photolithographically forming a light reflector layer of desired pattern; heating the light reflector layer under a predetermined temperature condition, thereby precipitating fine silver particles on the surface of the light reflector layer; and confronting a transparent substrate with the light reflector layer-formed substrate, and sandwiching a liquid crystal layer between the substrates.
    Type: Grant
    Filed: July 15, 1999
    Date of Patent: December 28, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Kagawa, Shinichi Komura, Katsumi Kondo, Yasunari Maekawa
  • Publication number: 20040233377
    Abstract: A liquid crystal display device having a pair of substrates, a liquid crystal layer, a group of electrodes for applying to the liquid crystal layer an electric field substantially parallel to the substrate surface, and a plurality of active elements connected to the electrodes, the group of electrodes and active elements being formed on one of the pair of substrates. An alignment control film is formed between the liquid crystal layer and at least one of the pair of substrates and is made from polyamic acid obtained by reacting a diamine with an acid anhydride.
    Type: Application
    Filed: June 24, 2004
    Publication date: November 25, 2004
    Inventors: Yuka Utsumi, Yasushi Tomioka, Masatoshi Wakagi, Yasunari Maekawa, Sukekazu Aratani, Katsumi Kondo, Shigeru Matsuyama
  • Patent number: 6757044
    Abstract: A normally closed liquid crystal display device using an in-plane switching mode prevented from light leakage caused by spacer beads and having a high contrast ratio can be produced by making a pretilt angle between an alignment control film and liquid crystals 4° or less and controlling a light leakage centering the spacer in 4-divided shapes; or by placing a film provided with a liquid crystal alignment controlling function by irradiation with polarized light between the spacer and a liquid crystal layer, the spacer being present in a pair of substrates.
    Type: Grant
    Filed: July 8, 2002
    Date of Patent: June 29, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yuka Utsumi, Yasushi Tomioka, Masatoshi Wakagi, Yasunari Maekawa, Sukekazu Aratani, Katsumi Kondo, Shigeru Matsuama
  • Publication number: 20030002005
    Abstract: A normally closed liquid crystal display device using an in-plane switching mode prevented from light leakage caused by spacer beads and having a high contrast ratio can be produced by making a pretilt angle between an alignment control film and liquid crystals 4° or less and controlling a light leakage centering the spacer in 4-divided shapes; or by placing a film provided with a liquid crystal alignment controlling function by irradiation with polarized light between the spacer and a liquid crystal layer, the spacer being present in a pair of substrates.
    Type: Application
    Filed: July 8, 2002
    Publication date: January 2, 2003
    Inventors: Yuka Utsumi, Yasushi Tomioka, Masatoshi Wakagi, Yasunari Maekawa, Sukekazu Aratani, Katsumi Kondo, Shigeru Matsuama
  • Patent number: 6441880
    Abstract: A normally closed liquid crystal display device using an in-plane switching mode prevented from light leakage caused by spacer beads and having a high contrast ratio can be produced by making a pretilt angle between an alignment control film and liquid crystals 4° or less and controlling a light leakage centering the spacer in 4-divided shapes; or by placing a film provided with a liquid crystal alignment controlling function by irradiation with polarized light between the spacer and a liquid crystal layer, the spacer being present in a pair of substrates.
    Type: Grant
    Filed: January 29, 1999
    Date of Patent: August 27, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Yuka Utsumi, Yasushi Tomioka, Masatoshi Wakagi, Yasunari Maekawa, Sukekazu Aratani, Katsumi Kondo, Shigeru Matsuyama
  • Patent number: 6291619
    Abstract: A photosensitive composition comprising a polyimide precursor, a photosensitive material having a structure represented by the following formula wherein A1 is an atom belonging to Group VI of the periodic table, in the molecule thereof and/or a photosensitive material having a structure represented by the following formula: wherein A2 is O, S or N atom, in the molecule thereof is suitable for formation of a positive tone pattern excellent in heat resistance, and applicable to electronic devices.
    Type: Grant
    Filed: July 29, 1999
    Date of Patent: September 18, 2001
    Assignee: Hitachi Chemical Co., LTD
    Inventors: Yasunari Maekawa, Takao Miwa, Takumi Ueno, Yoshiaki Okabe
  • Patent number: 5858584
    Abstract: A highly reliable positive type photosensitive resin composition composed of diamine having a carboxyl group as a structural unit, which can be developed with an alkaline aqueous solution, comprising polyamic acid ester having hydrophobic group, o-quinonediazidesulfonyl amide compound, and/or o-quinonediazidesulfonyl amide sulfonic ester compound, and electronic devices using the same. A polyamide film having preferable positive type relief patterns, of which the unexposed portion is not corroded, can be obtained.
    Type: Grant
    Filed: May 16, 1997
    Date of Patent: January 12, 1999
    Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.
    Inventors: Yoshiaki Okabe, Takao Miwa, Yasunari Maekawa, Takumi Ueno, Geraldine Rames-Langlade, Mina Ishida