Patents by Inventor Takafumi Kawanaka

Takafumi Kawanaka 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: 20220315683
    Abstract: Acrylic rubber bale excellent in storage stability and processability, a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber bale, and a cross-linked product of the rubber mixture are provided. The acrylic rubber bale includes an acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, wherein an amount of gel insoluble in methyl ethyl ketone is 50% by weight or less, and a specific gravity is 0.8 or more.
    Type: Application
    Filed: June 5, 2020
    Publication date: October 6, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220267491
    Abstract: An acrylic rubber bale excellent in storage stability and processability, a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber bale, and a rubber cross-linked product of the rubber mixture are provided. The acrylic rubber bale according to the present invention includes an acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, wherein an amount of gel insoluble in methyl ethyl ketone is 50% by weight or less, and pH is 6 or less.
    Type: Application
    Filed: June 5, 2020
    Publication date: August 25, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220259345
    Abstract: Acrylic rubber bale excellent in storage stability and processability, a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber bale, and a cross-linked product of the rubber mixture are provided. The acrylic rubber bale includes an acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, wherein an amount of gel insoluble in methyl ethyl ketone is 60% by weight or less, and a specific gravity is 0.8 or more.
    Type: Application
    Filed: July 17, 2020
    Publication date: August 18, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220259348
    Abstract: An acrylic rubber bale excellent in strength properties and processability, a method for producing the same, a rubber mixture containing the acrylic rubber bale, a method for producing the same, and a rubber cross-linked product of the same. The acrylic rubber bale includes an acrylic rubber mainly containing a (meth) acrylic acid ester having a weight average molecular weight (Mw) of 1,000,000 to 5,000,000, and a ratio (Mz/Mw) of a Z-average molecular weight (Mz) and a weight average molecular weight (Mw) is 1.3 or more, wherein an amount of gel insoluble in methyl ethyl ketone is 50% by weight or less.
    Type: Application
    Filed: June 5, 2020
    Publication date: August 18, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220259347
    Abstract: An acrylic rubber excellent in water resistance and a method for producing the same are provided. An acrylic rubber composed of: 70 to 99.9 wt % of a bonding unit derived from (meth) acrylic acid ester; 0.1 to 10 wt % of a bonding unit derived from a cross-linkable monomer; and if necessary, 0 to 20 wt % of a bonding unit derived from another monomer, wherein the ash content is 0.5 wt % or less, the total amount of magnesium and phosphorus in the ash is 30 wt % or more, a ratio of the magnesium to the phosphorus ([Mg]/[P]) by weight is 0.4 to 2.5, and Mooney viscosity (ML1+4, 100° C.) of the rubber is 10 to 150 is particularly excellent in water resistance, and a rubber cross-linked product using the same is also excellent in physical properties.
    Type: Application
    Filed: June 5, 2020
    Publication date: August 18, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220251265
    Abstract: Acrylic rubber bale having remarkably improved storage stability and water resistance without deteriorating cross-linking properties, a method of production, a rubber mixture obtained by mixing the acrylic rubber bale, a method of production, and a rubber cross-linked product obtained by cross-linking the same is provided. The acrylic rubber bale includes an acrylic rubber, and the acrylic rubber is mainly composed of (meth) acrylic acid ester, and has a weight average molecular weight of 100,000 to 5,000,000, and has a ratio of a Z-average molecular weight and a weight average molecular weight of 1.3 or more, where an ash content is 0.6% by weight or less, and the ash contains a periodic table group 2 metal and phosphorus, and a phosphorus content is 10% by weight or more, and the ratio of the periodic table group 2 metal to phosphorus is in the range of 0.6 to 2 molar ratio.
    Type: Application
    Filed: June 5, 2020
    Publication date: August 11, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Publication number: 20220235190
    Abstract: An acrylic rubber sheet excellent in storage stability and processability, a method for producing the same, an acrylic rubber bale obtained by laminating the sheets, a mixture obtained by mixing the acrylic rubber sheet and the acrylic rubber bale, a method for producing the mixture and a rubber cross-linking product obtained by cross-linking the mixture. The acrylic rubber sheet comprises, an acrylic rubber mainly composed of a (meth) acrylic acid ester and having a weight average molecular weight (Mw) of 100,000 to 5,000,000 and a ratio (Mz/Mw) of a Z-average molecular weight (Mz) and a weight average molecular weight (Mw) is 1.3 or more, and the acrylic rubber sheet contains a phenolic anti-aging agent, and a gel amount is 50 wt % or less. The acrylic rubber sheet is extremely excellent in storage stability and processability and the sheet can be easily produced by the claimed method.
    Type: Application
    Filed: June 5, 2020
    Publication date: July 28, 2022
    Applicant: ZEON CORPORATION
    Inventors: Hirofumi MASUDA, Takafumi KAWANAKA
  • Patent number: 8044147
    Abstract: A nitrile group-containing copolymer rubber comprising 10 to 40 wt % of ?,?-ethylenically unsaturated nitrile unit (a), 10 to 60 wt % of ?,?-ethylenically unsaturated carboxylic acid ester unit (b), and 20 to 70 wt % in total of conjugated diene unit (c) and saturated conjugated diene unit (d), wherein a content ratio “x” of a conjugated diene unit (c) based on the total content of said conjugated diene unit (c) and said saturated conjugated diene unit (d) is 0.08 or smaller, and “x·A” defined as a product of said ratio “x” and a content ratio “A” (%) of said ?,?-ethylenically unsaturated nitrile unit (a) is 1.5 or smaller. According to the present invention, a nitrile group-containing copolymer rubber capable to provide a rubber vulcanizate highly balanced in mechanical strength, heat aging resistance, oil resistance, cold resistance and ozone resistance, and a vulcanizable rubber composition using the rubber can be provided.
    Type: Grant
    Filed: February 22, 2006
    Date of Patent: October 25, 2011
    Assignee: Zeon Corporation
    Inventors: Hiroyasu Nagamori, Akira Tsukada, Takafumi Kawanaka
  • Patent number: 7923514
    Abstract: A process for hydrogenating a conjugated diene polymer wherein a conjugated diene polymer is hydrogenated in the presence of a catalyst comprising a platinum group metal or its compound, and a basic compound. More specifically, (1) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst and the basic compound in a solution or latex of the conjugated diene polymer; (2) hydrogenation is conducted in a reaction system prepared by incorporating a catalyst system comprising a combination of the catalyst with the basic compound, in a solution or latex of the conjugated diene polymer; or (3) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst in a solution of a composition comprising the conjugated diene polymer and the basic compound. Thus, a hydrogenated conjugated diene polymer can be efficiently and industrially advantageously produced using a small amount of a catalyst.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: April 12, 2011
    Assignee: Zeon Corporation
    Inventors: Kazuhiro Takahashi, Takafumi Kawanaka
  • Publication number: 20090124741
    Abstract: A nitrile group-containing copolymer rubber comprising 10 to 40 wt % of ?,?-ethylenically unsaturated nitrile unit (a), 10 to 60 wt % of ?,?-ethylenically unsaturated carboxylic acid ester unit (b), and 20 to 70 wt % in total of conjugated diene unit (c) and saturated conjugated diene unit (d), wherein a content ratio “x” of a conjugated diene unit (c) based on the total content of said conjugated diene unit (c) and said saturated conjugated diene unit (d) is 0.08 or smaller, and “x·A” defined as a product of said ratio “x” and a content ratio “A” (%) of said ?,?-ethylenically unsaturated nitrile unit (a) is 1.5 or smaller. According to the present invention, a nitrile group-containing copolymer rubber capable to provide a rubber vulcanizate highly balanced in mechanical strength, heat aging resistance, oil resistance, cold resistance and ozone resistance, and a vulcanizable rubber composition using the rubber can be provided.
    Type: Application
    Filed: February 22, 2006
    Publication date: May 14, 2009
    Inventors: Hiroyasu Nagamori, Akira Tsukada, Takafumi Kawanaka
  • Publication number: 20080132649
    Abstract: A process for hydrogenating a conjugated diene polymer wherein a conjugated diene polymer is hydrogenated in the presence of a catalyst comprising a platinum group metal or its compound, and a basic compound. More specifically, (1) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst and the basic compound in a solution or latex of the conjugated diene polymer; (2) hydrogenation is conducted in a reaction system prepared by incorporating a catalyst system comprising a combination of the catalyst with the basic compound, in a solution or latex of the conjugated diene polymer; or (3) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst in a solution of a composition comprising the conjugated diene polymer and the basic compound. Thus, a hydrogenated conjugated diene polymer can be efficiently and industrially advantageously produced using a small amount of a catalyst.
    Type: Application
    Filed: December 21, 2007
    Publication date: June 5, 2008
    Inventors: Kazuhiro Takahashi, Takafumi Kawanaka
  • Publication number: 20050158544
    Abstract: A latex of a cyano-bearing copolymer rubber which contains units derived from an ?,?-ethylenically unsaturated nitrile monomer in an amount of 10 to 30% by mass and has an iodine number of 250 or below, a Mooney viscosity (ML1+4, 100° C.) of 10 to 120, and a difference (?Tg) between extrapolated glass transition initiation temperature (Tig) and extrapolated glass transition ending temperature (Teg) of 15° C. or below as determined by differential scanning calorimetry; and fluid treatments for bonding and adhesive compositions, containing the latex. The adhesive compositions are excellent in heat resistance, oil resistance, and adhesion to vulcanized rubbers, and exhibit tackiness.
    Type: Application
    Filed: March 27, 2003
    Publication date: July 21, 2005
    Inventors: Masayuki Nakamura, Takafumi Kawanaka
  • Publication number: 20040242800
    Abstract: A process for hydrogenating a conjugated diene polymer wherein a conjugated diene polymer is hydrogenated in the presence of a catalyst comprising a platinum group metal or its compound, and a basic compound. More specifically, (1) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst and the basic compound in a solution or latex of the conjugated diene polymer; (2) hydrogenation is conducted in a reaction system prepared by incorporating a catalyst system comprising a combination of the catalyst with the basic compound, in a solution or latex of the conjugated diene polymer; or (3) hydrogenation is conducted in a reaction system prepared by incorporating the catalyst in a solution of a composition comprising the conjugated diene polymer and the basic compound. Thus, a hydrogenated conjugated diene polymer can be efficiently and industrially advantageously produced using a small amount of a catalyst.
    Type: Application
    Filed: March 19, 2004
    Publication date: December 2, 2004
    Inventors: Kazuhiro Takahashi, Takafumi Kawanaka
  • Patent number: 6657014
    Abstract: A crosslinkable rubber composition comprising (a) 100 weight parts of a nitrile group-containing highly saturated copolymer rubber containing units of an ethlenically unsaturated dicarboxylic acid monoalkyl ester monomer, (b) 0.5 to 10 parts by weight of a polyamine crosslinking agent, and (c) 0.5 to 10 parts by weight of a basic crosslinking accelerator. This rubber composition gives a crosslinked nitrile group-containing highly saturated copolymer rubber article having excellent heat resistance, flex fatigue resistance and elongation, and reduced permanent set.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: December 2, 2003
    Assignee: Zeon Corporation
    Inventors: Osamu Mori, Takafumi Kawanaka, Yoshiaki Aimura, Hiroyuki Kotsuji, Haruhiko Fujita
  • Patent number: 5334683
    Abstract: There are provided an acrylate polymer elastomer containing a particular acrylic ester unit as a constitutive component, and a vulcanizable composition comprising the elastomer and a vulcanizing agent.The acrylate polymer elastomer is obtained by copolymerizing(a) 45 to 89.9 wt. % of a monomer represented a by the formula ##STR1## wherein R.sup.1 represents an alkyl group having 1 to 8 carbon atoms, and/or a monomer represented by the formula ##STR2## wherein R.sup.2 represents an alkylene group having 1 to 8 carbon atoms and R.sup.3 represents an alkyl group having 1 to 8 carbon atoms,(b) 10 to 35 wt. % of a monomer represented by the formula t,0012wherein R.sup.4 represents a hydrogen atom or a methyl group, R.sup.5 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 to 5,(c) 0.1 to 10 wt. % of crosslinkable monomer, and(d) 0 to 30 wt. % of a monoethylenic unsaturated monomer copolymerizable with the above(a) , (b) and (c) components.
    Type: Grant
    Filed: March 30, 1993
    Date of Patent: August 2, 1994
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Takafumi Kawanaka, Takeshi Ohishi, Masahiro Shimizu
  • Patent number: 5294233
    Abstract: An additive for improving the dispersibility of a particulate substance in an organic medium, a thermoplastic polymer, or a thermosetting resin, is at least one compound having a ##STR1## bond in the molecule, including, for example, compounds having an oxazolinium ion in the molecule. The preferred additive compounds are oligomeric or polymeric.
    Type: Grant
    Filed: July 31, 1991
    Date of Patent: March 15, 1994
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Shizuo Kitahara, Hiroyuki Watanabe, Takuji Kishimoto, Tetuya Toyoshima, Takafumi Kawanaka, Kohkichi Noguchi
  • Patent number: 5280080
    Abstract: There are provided an acrylic copolymer elastomer containing an acrylic acid polyalkylene glycol ester as a constituent, and a vulcanizable composition comprising said elastomer and a vulcanizing agent, which composition gives a vulcanizate excellent in cold resistance, heat resistance and oil resistance. The acrylic copolymer elastomer is obtained by copolymerizing(a) 45 to 89.9% by weight of a monomer represented by the formula ##STR1## wherein R.sup.1 denotes an alkyl group having 1 to 8 carbon atoms, and/or a monomer represented by the formula ##STR2## wherein R.sup.2 denotes an alkylene group having 1 to 8 carbon atoms, and R.sup.3 denotes an alkyl group having 1 to 8 carbon atoms,(b) 10 to 45% by weight of a monomer represented by the formula ##STR3## wherein R.sup.4 denotes a hydrogen atom or a methyl group, R.sup.5 denotes a hydrocarbon group having 1 to 8 carbon atoms, m is an integer of 2 to 10, and n is an integer of 2 to 3,(c) 0.
    Type: Grant
    Filed: February 25, 1993
    Date of Patent: January 18, 1994
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Takafumi Kawanaka, Kiyoshi Hosoya
  • Patent number: 5216101
    Abstract: There are provided an acrylic copolymer elastomer containing an acrylic acid polyalkylene glycol ester as a constituent, and a vulcanizable composition comprising said elastomer and a vulcanizing agent, which composition gives a vulcanizate excellent in cold resistance, heat resistance and oil resistance. The acrylic copolymer elastomer is obtained by copolymerizing(a) 45 to 89.9% by weight of a monomer represented by the formula ##STR1## wherein R.sup.1 denotes an alkyl group having 1 to 8 carbon atoms, and/or a monomer represented by the formula ##STR2## wherein R.sup.2 denotes an alkylene group having 1 to 8 carbon atoms, and R.sup.3 denotes an alkyl group having 1 to 8 carbon atoms,(b) 10 to 45% by weight of a monomer represented by the formula ##STR3## wherein R.sup.4 denotes a hydrogen atom or a methyl group, R.sup.5 denotes a hydrocarbon group having 1 to 8 carbon atoms, m is an integer of 2 to 10, and n is an integer of 2 to 3,(c) 0.
    Type: Grant
    Filed: September 29, 1992
    Date of Patent: June 1, 1993
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Takafumi Kawanaka, Kiyoshi Hosoya
  • Patent number: 5001196
    Abstract: An improved diene type polymer rubber is prepared by reacting a diene type polymer rubber, to which an alkali metal and/or an alkaline earth metal has been added, with a compound represented by the formula: ##STR1## wherein M is oxygen or sulfur, R.sub.1 and R.sub.4 are a substituent having no hydrogen on the .alpha.-carbon atom, R.sub.2 and R.sub.3 are hydrogen or a hydrocarbon group, m is an integer of at least 2, and n is an integer of 2 to 4. The diene type polymer rubber is characterized in that, even after storage for a long time, the Mooney viscosity rises only to a very slight extent, and the rebound, wet skid resistance and other physical properties of the cured product thereof are not substantially changed.
    Type: Grant
    Filed: March 29, 1989
    Date of Patent: March 19, 1991
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Takafumi Kawanaka, Hiroyuki Watanabe, Kohkichi Noguchi, Shuichi Akita