Patents by Inventor Shojiro Kaita

Shojiro Kaita 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: 20210061936
    Abstract: It is an object of the disclosure to provide a production method for a copolymer in which a copolymer with a high content of cis-1,4 bonds of a conjugated diene portion can be obtained at a high yield even when a cyclic olefin compound is used as a monomer.
    Type: Application
    Filed: August 28, 2018
    Publication date: March 4, 2021
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Shigenaga TAKANO, Shojiro KAITA, Olivier TARDIF
  • Patent number: 10875937
    Abstract: An object of the present disclosure is to provide a terminal-modified conjugated dime polymer capable of improving fracture resistance of a rubber article. Specifically, a terminal-modified conjugated diene polymer is characterized in that a content of catalyst residue therein derived from a catalyst used in polymerization is less than 60 ppm.
    Type: Grant
    Filed: April 27, 2017
    Date of Patent: December 29, 2020
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Yusuke Yamagata, Shojiro Kaita, Shigenaga Takano
  • Patent number: 10875952
    Abstract: An object of the present invention is to provide a multicomponent copolymer for use for producing a rubber composition and a rubber product having high abrasion resistance and wet performance. Further, the invention is to provide a rubber composition containing the multicomponent copolymer, a crosslinked rubber composition produced by crosslinking the rubber composition, and a tire and a rubber product using the rubber composition or the crosslinked rubber composition. The multicomponent copolymer of the invention contains a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, wherein the content of the aromatic vinyl unit is 5 mol % or more and less than 50 mol % of the whole multicomponent copolymer and the content of the non-conjugated olefin unit is more than 0 mol % and 50 mol % or less of the whole multicomponent copolymer.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: December 29, 2020
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Kyohei Kotani, Shigenaga Takano, Shigeki Oishi, Shojiro Kaita
  • Publication number: 20200347169
    Abstract: To provide a catalyst composition having high polymerization activity. To provide a polymer manufacturing method. To provide a polymer manufactured by the polymer manufacturing method. To provide a rubber composition including the polymer. To provide a tire using the rubber composition. A catalyst composition including a compound represented by Structural Formula I below, wherein the compound has an OH group at at least one position of the bipyridyl ring; M is a transition metal, a lanthanoid, scandium, or yttrium; R1 and R2 are a hydrocarbon group having one or more carbon atoms or a halogen atom; and R1 and R2 may be the same or different from each other. A polymer manufacturing method including a step of polymerizing one or more selected from the group consisting of a conjugated diene compound and a compound having an ethylenically unsaturated double bond in the presence of the catalyst composition. A polymer manufactured by the manufacturing method. A rubber composition including the polymer.
    Type: Application
    Filed: August 28, 2018
    Publication date: November 5, 2020
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Shigenaga TAKANO, Shojiro KAITA, Kohtaro OSAKADA, Duisuke TAKEUCHI, Shinji YAMAKAWA
  • Patent number: 10793658
    Abstract: An object of the present invention is to provide a multicomponent copolymer for use for producing a rubber composition and a rubber product such as tires and the like excellent in crack resistance and further having low heat generation while maintaining high weather resistance. Further, the present invention is to provide a rubber composition containing the multicomponent copolymer, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a rubber product and a tire using the rubber composition or the crosslinked rubber composition. The multicomponent copolymer of the present invention contains a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, wherein the main chain is formed of an acyclic structure alone and the content of the aromatic vinyl unit is 5 mol % or less of the whole multicomponent copolymer.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: October 6, 2020
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Madoka Kimura, Aya Yanagisawa, Shigeki Oishi, Shojiro Kaita
  • Publication number: 20190375923
    Abstract: A method, of the present disclosure, of producing a modified conjugated diene-based polymer includes a polymerization reaction process of polymerizing a conjugated diene monomer in the presence of a polymerization catalyst composition to obtain a conjugated diene-based polymer, an organic metal compound adding process of adding an organic metal compound after the polymerization reaction process, and a modification reaction process of modifying the conjugated diene-based polymer with a modifying agent after the organic metal compound adding process. A rubber composition of the present disclosure includes a modified conjugated diene-based polymer produced by the method. A tire of the present disclosure includes the rubber composition.
    Type: Application
    Filed: August 15, 2019
    Publication date: December 12, 2019
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Yusuke YAMAGATA, Shojiro KAITA, Tomoe TANABE
  • Publication number: 20190161571
    Abstract: An object of the present disclosure is to provide a terminal-modified conjugated diene polymer having a high cis-1,4 content and a low molecular weight distribution value and being excellent in durability (such as wear resistance, fracture resistance, cracking resistance, and the like). In order to achieve the object, a terminal-modified conjugated diene polymer of the present disclosure characteristically has: molecular weight distribution determined by gel permeation chromatography (GPC) of less than 2; and content of cis-1,4 bond of 95% or more.
    Type: Application
    Filed: March 29, 2017
    Publication date: May 30, 2019
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Yusuke YAMAGATA, Shojiro KAITA, Shigenaga TAKANO
  • Publication number: 20190153123
    Abstract: An object of the present disclosure is to provide a terminal-modified conjugated diene polymer capable of improving fracture resistance of a rubber article. Specifically, a terminal-modified conjugated diene polymer is characterized in that a content of catalyst residue therein derived from a catalyst used in polymerization is less than 60 ppm.
    Type: Application
    Filed: April 27, 2017
    Publication date: May 23, 2019
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Yusuke YAMAGATA, Shojiro KAITA, Shigenaga TAKANO
  • Patent number: 10239964
    Abstract: A method for manufacturing a conjugated diene polymer that can increase the robustness of a polymerization reaction system is provided. Also, a conjugated diene polymer, with a high cis-1,4-bond content, that is manufactured by this method for manufacturing is provided. A method for manufacturing a conjugated diene polymer includes polymerizing a conjugated diene monomer using a polymerization catalyst composition including a rare earth element compound and a compound having a cyclopentadiene skeleton, and a conjugated diene polymer manufactured with this method for manufacturing has a cis-1,4-bond content of 95% or greater.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: March 26, 2019
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Yusuke Yamagata, Narukuni Hirata, Tomoe Tanabe, Shojiro Kaita, Madoka Kimura
  • Publication number: 20190055395
    Abstract: Provided is a rubber composition that contains a rubber component having excellent cold flow resistance and has improved low loss property and wear resistance as compared to conventional ones. The rubber composition comprises: a modified conjugated diene-based polymer having a hydroxyl group at a terminal; and at least one of a natural rubber or a polyisoprene rubber. The modified conjugated diene-based polymer preferably has a cis-1,4 bond content of 95% or more; the modified conjugated diene-based polymer preferably has a molecular weight distribution (Mw/Mn) of 2.5 or less; and a content of the modified conjugated diene-based polymer in a rubber component is preferable to be 20 mass % or more.
    Type: Application
    Filed: January 13, 2017
    Publication date: February 21, 2019
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Yusuke YAMAGATA, Shojiro KAITA
  • Patent number: 10131722
    Abstract: This disclosure is to provide a method for preparing a terminal-modified conjugated diene polymer which achieves an extremely high compounding amount of cis-1,4 without complicated preparing conditions, a terminal-modified conjugated diene polymer obtained via the method, a rubber composition containing the terminal-modified conjugated diene polymer, and a tire using the rubber composition.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: November 20, 2018
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Narukuni Hirata, Yusuke Yamagata, Tomoe Tanabe, Shojiro Kaita
  • Publication number: 20180298136
    Abstract: An object of the present invention is to provide a multicomponent copolymer for use for producing a rubber composition and a rubber product having high abrasion resistance and wet performance. Further, the invention is to provide a rubber composition containing the multicomponent copolymer, a crosslinked rubber composition produced by crosslinking the rubber composition, and a tire and a rubber product using the rubber composition or the crosslinked rubber composition. The multicomponent copolymer of the invention contains a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, wherein the content of the aromatic vinyl unit is 5 mol % or more and less than 50 mol % of the whole multicomponent copolymer and the content of the non-conjugated olefin unit is more than 0 mol % and 50 mol % or less of the whole multicomponent copolymer.
    Type: Application
    Filed: October 14, 2016
    Publication date: October 18, 2018
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Kyohei KOTANI, Shigenaga TAKANO, Shigeki OISHI, Shojiro KAITA
  • Publication number: 20180298135
    Abstract: An object of the present invention is to provide a multicomponent copolymer for use for producing a rubber composition and a rubber product such as tires and the like excellent in crack resistance and further having low heat generation while maintaining high weather resistance. Further, the present invention is to provide a rubber composition containing the multicomponent copolymer, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a rubber product and a tire using the rubber composition or the crosslinked rubber composition. The multicomponent copolymer of the present invention contains a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, wherein the main chain is formed of an acyclic structure alone and the content of the aromatic vinyl unit is 5 mol % or less of the whole multicomponent copolymer.
    Type: Application
    Filed: October 14, 2016
    Publication date: October 18, 2018
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Madoka KIMURA, Aya YANAGISAWA, Shigeki OISHI, Shojiro KAITA
  • Patent number: 10087312
    Abstract: Provided is a rubber composition including a rubber component. The rubber component contains at least a polymer that is a synthesized polyisoprene or an isoprene copolymer and that has 20% or less gel fraction.
    Type: Grant
    Filed: December 6, 2017
    Date of Patent: October 2, 2018
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Junko Matsushita, Shojiro Kaita, Satoru Tamaki
  • Patent number: 10053530
    Abstract: Provided is a method for producing a multicomponent copolymer comprising copolymerizing a conjugated diene compound, a non-conjugated olefin compound, and an aromatic vinyl compound to produce a multicomponent copolymer having a main chain consisting of an acyclic structure.
    Type: Grant
    Filed: June 3, 2015
    Date of Patent: August 21, 2018
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Shigeki Oishi, Shojiro Kaita
  • Patent number: 9938362
    Abstract: An isoprene polymerization catalyst composition includes: Component (a): a rare earth element compound having a rare earth element-oxygen bond or a rare earth element-sulfur bond; Component (b): an ionic compound; and Component (c): at least one compound selected from the group consisting of a compound of formula (X): YR1aR2bR3c and a compound having a repeating unit of formula (Y): (—Y(R1)O—) (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3is a C1-10 hydrocarbon group).
    Type: Grant
    Filed: February 14, 2014
    Date of Patent: April 10, 2018
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Shojiro Kaita, Satoru Tamaki
  • Publication number: 20180094124
    Abstract: Provided is a rubber composition including a rubber component. The rubber component contains at least a polymer that is a synthesized polyisoprene or an isoprene copolymer and that has 20% or less gel fraction.
    Type: Application
    Filed: December 6, 2017
    Publication date: April 5, 2018
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Junko MATSUSHITA, Shojiro Kaita, Satoru Tamaki
  • Patent number: 9796801
    Abstract: The polymerization catalyst composition includes: Component (A): a rare earth element compound of formula (i): M-(NQ1)(NQ2)(NQ3) (where M is at least one selected from lanthanoid, scandium, and yttrium, and NQ1, NQ2 and NQ3 are amide groups and each have a M-N bond; Component (B): a hydrocarbyl aluminoxane compound having a C1-20 hydrocarbon group; and Component (C): a compound of formula (X): YR1aR2bR3c (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3 is a C1-10 hydrocarbon group).
    Type: Grant
    Filed: February 14, 2014
    Date of Patent: October 24, 2017
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Shojiro Kaita, Satoru Tamaki
  • Patent number: 9777101
    Abstract: A copolymer having properties (durability (fracture resistance, abrasion resistance, and crack-growth resistance)) similar to those of natural rubber and a method of producing the copolymer are provided. An isoprene copolymer has a styrene block or a butadiene block at a terminal thereof, wherein styrene monomers account for less than 5 mol % of all monomers forming the isoprene copolymer having the styrene block; butadiene monomers account for 10 mol % or less of all monomers forming the isoprene copolymer having the butadiene block; and cis-1,4 bond content of a portion derived from isoprene accounts for at least 95% in total.
    Type: Grant
    Filed: July 11, 2013
    Date of Patent: October 3, 2017
    Assignee: BRIDGESTONE CORPORATION
    Inventors: Satoru Tamaki, Junko Matsushita, Shojiro Kaita
  • Publication number: 20170275400
    Abstract: This disclosure is to provide a method for preparing a terminal-modified conjugated diene polymer which achieves an extremely high compounding amount of cis-1,4 without complicated preparing conditions, a terminal-modified conjugated diene polymer obtained via the method, a rubber composition containing the terminal-modified conjugated diene polymer, and a tire using the rubber composition.
    Type: Application
    Filed: July 2, 2015
    Publication date: September 28, 2017
    Applicant: BRIDGESTONE CORPORATION
    Inventors: Narukuni HIRATA, Yusuke YAMAGATA, Tomoe TANABE, Shojiro KAITA