Patents by Inventor Takashi Shirokawa

Takashi Shirokawa 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: 10072138
    Abstract: A rubber composition comprises a diene rubber including not less than 30% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 1 to 25 parts by weight of a tackifying resin, and from 25 to 80 parts by weight of a filler comprising not less than 50% by weight of silica. The modified conjugated diene polymer rubber has a terminal modified group comprising a functional group that interacts with silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, weight-average molecular weight is from 600,000 to 1,000,000, and glass transition temperature is from ?22 to ?32° C. A glass transition temperature of the tackifying resin is from 50 to 110° C. higher than the glass transition temperature of the modified conjugated diene polymer rubber.
    Type: Grant
    Filed: November 25, 2011
    Date of Patent: September 11, 2018
    Assignee: The Yokohama Rubber Co., LTD
    Inventors: Ayumi Naka, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Masaki Satou
  • Patent number: 9567451
    Abstract: A rubber composition for use in tire treads comprises a diene rubber including not less than 40% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 66 to 110 parts by weight of a filler. The filler comprises not less than 50% by weight of silica. The modified conjugated diene polymer rubber is obtained by copolymerizing a conjugated diene monomer unit and an aromatic vinyl monomer unit in a hydrocarbon solvent using an organic active metal compound as an initiator. A resulting active conjugated diene polymer chain thereof has a terminal modified group, obtained by reacting at least one type of compound having a functional group that is reactable with the active terminal of the polymer chain. Moreover, the terminal modified group has a functional group that interacts with the silica.
    Type: Grant
    Filed: November 25, 2011
    Date of Patent: February 14, 2017
    Assignee: The Yokohama Rubber Co., LTD.
    Inventors: Masaki Satou, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Ayumi Naka, Keisuke Maejima
  • Patent number: 9416252
    Abstract: A rubber composition comprises a diene rubber including not less than 25% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 25 to 65 parts by weight of a filler, the filler comprising not less than 50% by weight of silica. The silica has a DBP absorption number of 190 to 250 ml/100 g, an N2SA of 194 to 225 m/g, and a CTAB of 185 to 215 m2/g. A ratio of the N2SA to the CTAB is from 0.9 to 1.4. The modified conjugated diene polymer rubber has a terminal modified group including a functional group that interacts with the silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, and weight-average molecular weight is from 600,000 to 1,000,000.
    Type: Grant
    Filed: November 25, 2011
    Date of Patent: August 16, 2016
    Assignee: The Yokohama Rubber Co., LTD.
    Inventors: Ayumi Naka, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Masaki Satou, Keisuke Maejima
  • Publication number: 20140011909
    Abstract: A rubber composition for use in tire treads comprises a diene rubber including not less than 40% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 66 to 110 parts by weight of a filler. The filler comprises not less than 50% by weight of silica. The modified conjugated diene polymer rubber is obtained by copolymerizing a conjugated diene monomer unit and an aromatic vinyl monomer unit in a hydrocarbon solvent using an organic active metal compound as an initiator. A resulting active conjugated diene polymer chain thereof has a terminal modified group, obtained by reacting at least one type of compound having a functional group that is reactable with the active terminal of the polymer chain. Moreover, the terminal modified group has a functional group that interacts with the silica.
    Type: Application
    Filed: November 25, 2011
    Publication date: January 9, 2014
    Applicant: The Yokohama Rubber Co., Ltd.
    Inventors: Masaki Satou, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Ayumi Naka, Keisuke Maejima
  • Publication number: 20130338255
    Abstract: A rubber composition comprises a diene rubber including not less than 25% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 25 to 65 parts by weight of a filler, the filler comprising not less than 50% by weight of silica. The silica has a DBP absorption number of 190 to 250 ml/100 g, an N2SA of 194 to 225 m/g, and a CTAB of 185 to 215 m2/g. A ratio of the N2SA to the CTAB is from 0.9 to 1.4. The modified conjugated diene polymer rubber has a terminal modified group including a functional group that interacts with the silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, and weight-average molecular weight is from 600,000 to 1,000,000.
    Type: Application
    Filed: November 25, 2011
    Publication date: December 19, 2013
    Applicant: The Yokohama Rubber Co., LTD.
    Inventors: Ayumi Naka, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Masaki Satou, Keisuke Maejima
  • Publication number: 20130324638
    Abstract: A rubber composition comprises a diene rubber including not less than 30% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 1 to 25 parts by weight of a tackifying resin, and from 25 to 80 parts by weight of a filler comprising not less than 50% by weight of silica. The modified conjugated diene polymer rubber has a terminal modified group comprising a functional group that interacts with silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, weight-average molecular weight is from 600,000 to 1,000,000, and glass transition temperature is from ?22 to ?32° C. A glass transition temperature of the tackifying resin is from 50 to 110° C. higher than the glass transition temperature of the modified conjugated diene polymer rubber.
    Type: Application
    Filed: November 25, 2011
    Publication date: December 5, 2013
    Applicant: THE YOKOHAMA RUBBER CO., LTD.
    Inventors: Ayumi Naka, Takashi Shirokawa, Makoto Ashiura, Yoshihiro Kameda, Masaki Satou
  • Patent number: 7919558
    Abstract: A rubber composition containing (i) a conjugated diene-based rubber gel having a toluene swelling index of 16 to 70, (ii) a diene-based rubber such as natural rubber, polyisoprene rubber, aromatic vinyl-conjugated diene copolymer rubber and/or polybutadiene rubber, and (iii) an optional carbon black and/or silica and (a) a pneumatic tire using this composition as a high hardness reinforcing layer extending from a bead along a tire sidewalls, in which the fluidity and dimensional stability at the time of extrusion are improved, while maintaining a sufficient hardness of a high hardness reinforced rubber, (b) a pneumatic tire using this composition as two ends of a tire tread extrudate, maintaining a flex fatigue of the two ends of the tread, in which the extrudability and extrusion dimensional stability are improved and (c) a pneumatic tire using the composition as a 1.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: April 5, 2011
    Assignees: The Yokohama Rubber Co., Ltd., Zeon Corporation
    Inventors: Naoya Amino, Misao Hiza, Takashi Shirokawa, Masao Nakamura, Koichi Endo
  • Publication number: 20070167555
    Abstract: A rubber composition containing (i) a conjugated diene-based rubber gel having a toluene swelling index of 16 to 70, (ii) a diene-based rubber such as natural rubber, polyisoprene rubber, aromatic vinyl-conjugated diene copolymer rubber and/or polybutadiene rubber, and (iii) an optional carbon black and/or silica and (a) a pneumatic tire using this composition as a high hardness reinforcing layer extending from a bead along a tire sidewalls, in which the fluidity and dimensional stability at the time of extrusion are improved, while maintaining a sufficient hardness of a high hardness reinforced rubber, (b) a pneumatic tire using this composition as two ends of a tire tread extrudate, maintaining a flex fatigue of the two ends of the tread, in which the extrudability and extrusion dimensional stability are improved and (c) a pneumatic tire using the composition as a 1.
    Type: Application
    Filed: February 22, 2005
    Publication date: July 19, 2007
    Applicants: The Yokohama Rubber Co., Ltd., Zeon Corporation
    Inventors: Naoya Amino, Misao Hiza, Takashi Shirokawa, Masao Nakamura, Koichi Endo
  • Publication number: 20060148979
    Abstract: A rubber composition containing 100 parts by weight of a diene-based rubber and 0.5 to 25 parts by weight of a heat expandable microcapsule composed of a thermoplastic resin particle having a substance enclosed therein, capable of vaporizing or expanding due to heat to thereby generate a gas, wherein a shell of the heat expandable microcapsule comprises a thermoplastic resin obtained by polymerization from, as a main component of a monomer, a nitrile-based monomer (I), a monomer (II) having an unsaturated double bond and carboxyl group in the molecule thereof, a monomer (III) having two or more polymerizable double bonds and, optionally, a copolymerizable monomer (IV) for adjusting the expansion characteristics, and a pneumatic tire using the same, whereby the tire weight is decreased and the ice traction thereof is improved.
    Type: Application
    Filed: October 12, 2004
    Publication date: July 6, 2006
    Inventors: Makio Mori, Takayuki Fukutomi, Takashi Shirokawa, Tomoaki Sugiyama, Shinya Takeda, Toshiaki Masuda, Yoshiaki Shirakabe
  • Patent number: 6730710
    Abstract: A rubber composition comprising 100 parts by weight of a diene rubber and 0.5 to 20 parts by weight of a foaming agent-containing resin containing 5 to 65% by weight of a chemical foaming agent, wherein the resin is mainly a polyolefin resin which is not co-crosslinkable with the diene rubber and wherein the rubber composition is structured having microcapsule-shaped bubbles coated with a resin layer after vulcanization of the rubber.
    Type: Grant
    Filed: December 6, 2002
    Date of Patent: May 4, 2004
    Assignee: The Yokohama Rubber Co, Ltd.
    Inventors: Makio Mori, Takeshi Hotaka, Takashi Shirokawa
  • Publication number: 20030119927
    Abstract: A rubber composition comprising 100 parts by weight of a diene rubber and 0.5 to 20 parts by weight of a foaming agent-containing resin containing 5 to 65% by weight of a chemical foaming agent, wherein the resin is mainly a polyolefin resin which is not co-crosslinkable with the diene rubber and wherein the rubber composition is structured having microcapsule-shaped bubbles coated with a resin layer after vulcanization of the rubber.
    Type: Application
    Filed: December 6, 2002
    Publication date: June 26, 2003
    Inventors: Makio Mori, Takeshi Hotaka, Takashi Shirokawa
  • Patent number: 6180711
    Abstract: This invention relates to a rubber composition for seismic isolation laminate which exhibits excellent damping capacity as well as sufficient hardening properties. Such rubber composition for a seismic isolation laminate comprises at least a diene rubber; and 40 to 160 parts by weight of carbon black having a CTAB specific surface area of 120 to 370 (m2/g) and a CTAB specific surface area (m2/g)/iodine adsorption (mg/g) of up to 1.0 per 100 parts by weight of the diene rubber.
    Type: Grant
    Filed: July 21, 1999
    Date of Patent: January 30, 2001
    Assignee: The Yokohama Rubber Co., Ltd.
    Inventors: Jun Shimada, Hideyuki Oishi, Takashi Shirokawa
  • Patent number: 5484836
    Abstract: A rubber composition for a tire tread comprising (i) 100 parts by weight of a diene based rubber containing at least one styrene-butadiene copolymer rubber having a glass transition temperature of -60.degree. C. to -20.degree. C. and (ii) 20 to 75 parts by weight of carbon black having CTAB of 85 to 110 m.sup.2 /g, C-DBP of more than 105 ml/100 g, N.sub.2 SA/IA of more than 1.10, Tint of more than 105, .DELTA.Dst of 60 to 80 nm, and CTAB of less than 230-5.8 (dn) wherein dn is the average particle size (nm), measured by an electron microscope.
    Type: Grant
    Filed: September 7, 1994
    Date of Patent: January 16, 1996
    Assignee: The Yokohama Rubber Co., Ltd.
    Inventors: Yasushi Kikuchi, Tetsuo Ochiai, Takashi Shirokawa, Hajime Fujii