Patents by Inventor Takashi Houkawa

Takashi Houkawa 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: 20220234986
    Abstract: Provided is a phenol compound represented by general formula (I), shown below. In general formula (I), R1 and R2 each indicate, independently of each other, a hydrogen atom or an alkyl group.
    Type: Application
    Filed: July 15, 2020
    Publication date: July 28, 2022
    Applicant: ZEON CORPORATION
    Inventors: Yosuke HARAUCHI, Takashi HOUKAWA
  • Patent number: 11192976
    Abstract: The present invention provides: a copolymer (A) which is a copolymer obtained by copolymerizing one or plural cycloolefin monomers and one or plural acyclic olefin monomers, or a copolymer obtained by copolymerizing two or more cycloolefin monomers, wherein the glass transition temperature (Tg) of the copolymer is 100° C. or higher, the refractive index of the copolymer is 1.545 or higher, and the Abbe's number of the copolymer is 50 or larger, and at least one of the cycloolefin monomers is a deltacyclene.
    Type: Grant
    Filed: April 2, 2020
    Date of Patent: December 7, 2021
    Assignee: ZEON CORPORATION
    Inventors: Kensaku Fujii, Takashi Houkawa, Takuya Komatsubara, Yasuhiro Shimizu
  • Publication number: 20200231745
    Abstract: The present invention provides: a copolymer (A) which is a copolymer obtained by copolymerizing one or plural cycloolefin monomers and one or plural acyclic olefin monomers, or a copolymer obtained by copolymerizing two or more cycloolefin monomers, wherein the glass transition temperature (Tg) of the copolymer is 100° C. or higher, the refractive index of the copolymer is 1.545 or higher, and the Abbe's number of the copolymer is 50 or larger, and at least one of the cycloolefin monomers is a deltacyclene.
    Type: Application
    Filed: April 2, 2020
    Publication date: July 23, 2020
    Applicant: ZEON CORPORATION
    Inventors: Kensaku FUJII, Takashi HOUKAWA, Takuya KOMATSUBARA, Yasuhiro SHIMIZU
  • Patent number: 10647811
    Abstract: The present invention provides: a copolymer (A) which is a copolymer obtained by copolymerizing one or plural cycloolefin monomers and one or plural acyclic olefin monomers, or by copolymerizing two or more cycloolefin monomers, wherein a glass transition temperature (Tg) is 100° C. or higher, a refractive index is 1.545 or higher, and an Abbe's number is 50 or larger; a polymer (B) selected from: a ring-opening homopolymer obtained by ring-opening polymerization of only a monomer represented by formula (I), a ring-opening copolymer obtained by ring-opening copolymerization of the monomer represented by formula (I) and a monomer capable of ring-opening copolymerization with the monomer represented by formula (I), a hydrogenated product of the ring-opening homopolymer and a hydrogenated product of the ring-opening copolymer; a forming material containing the copolymer (A) or the polymer (B); and a resin formed article obtained by forming the forming material.
    Type: Grant
    Filed: April 5, 2016
    Date of Patent: May 12, 2020
    Assignee: ZEON CORPORATION
    Inventors: Kensaku Fujii, Takashi Houkawa, Takuya Komatsubara, Yasuhiro Shimizu
  • Patent number: 10280253
    Abstract: The present invention is a hydrogenated cycloolefin ring-opening polymer comprising a repeating unit derived from tetracyclododecene, and a repeating unit derived from an additional norbornene-based monomer, the hydrogenated cycloolefin ring-opening polymer having a racemo diad ratio of 65% or more with respect to the repeating unit derived from tetracyclododecene, the hydrogenated cycloolefin ring-opening polymer having a weight average molecular weight (Mw) of 10,000 to 40,000, and a resin formed article obtained by forming the hydrogenated cycloolefin ring-opening polymer having a glass transition temperature of 140 to 165° C., a melt flow rate of 8 g/10 min or more as measured at a temperature of 280° C. under a load of 21.18 N, and a flexural strength of 60 MPa or more as measured by a flexural test at a test speed of 2 mm/min, and a resin formed article, and an optical member.
    Type: Grant
    Filed: September 24, 2015
    Date of Patent: May 7, 2019
    Assignee: Zeon Corporation
    Inventors: Akira Furuko, Takashi Houkawa, Ayumi Sato, Kenji Umeda
  • Publication number: 20180188420
    Abstract: The invention is a resin composition comprising an alicyclic-structure-containing polymer, a hindered-phenol-based antioxidant and a hindered amine compound, wherein the hindered-phenol-based antioxidant is a compound having a group represented by the specific formula, the hindered amine compound is a compound having a group represented by the specific formula in its molecule, a content of the hindered-phenol-based antioxidant is 0.1 to 2.0 parts by weight based on 100 parts by weight of the alicyclic-structure-containing polymer, and a content of the hindered amine compound is more than 0 to 1.0 part by weight based on 100 parts by weight of the alicyclic-structure-containing polymer, and a resin formed article, and an optical member. One aspect of the invention provides a resin composition which is hardly burned during forming, has excellent long-term thermal yellowing resistance and also suppresses adhesion of foreign matters due to charge, a resin formed article, and an optical member.
    Type: Application
    Filed: March 30, 2016
    Publication date: July 5, 2018
    Applicant: ZEON CORPORATION
    Inventors: Akira FURUKO, Ayumi SATO, Taichi SAWAGUCHI, Kensaku FUJII, Takashi HOUKAWA
  • Publication number: 20180086877
    Abstract: The present invention provides: a copolymer (A) which is a copolymer obtained by copolymerizing one or plural cycloolefin monomers and one or plural acyclic olefin monomers, or by copolymerizing two or more cycloolefin monomers, wherein a glass transition temperature (Tg) is 100° C. or higher, a refractive index is 1.545 or higher, and an Abbe's number is 50 or larger; a polymer (B) selected from: a ring-opening homopolymer obtained by ring-opening polymerization of only a monomer represented by formula (I), a ring-opening copolymer obtained by ring-opening copolymerization of the monomer represented by formula (I) and a monomer capable of ring-opening copolymerization with the monomer represented by formula (I), a hydrogenated product of the ring-opening homopolymer and a hydrogenated product of the ring-opening copolymer; a forming material containing the copolymer (A) or the polymer (B); and a resin formed article obtained by forming the forming material.
    Type: Application
    Filed: April 5, 2016
    Publication date: March 29, 2018
    Applicant: ZEON CORPORATION
    Inventors: Kensaku FUJII, Takashi HOUKAWA, Takuya KOMATSUBARA, Yasuhiro SHIMIZU
  • Publication number: 20170306080
    Abstract: The present invention is a hydrogenated cycloolefin ring-opening polymer comprising a repeating unit derived from tetracyclododecene, and a repeating unit derived from an additional norbornene-based monomer, the hydrogenated cycloolefin ring-opening polymer having a racemo diad ratio of 65% or more with respect to the repeating unit derived from tetracyclododecene, the hydrogenated cycloolefin ring-opening polymer having a weight average molecular weight (Mw) of 10,000 to 40,000, and a resin formed article obtained by forming the hydrogenated cycloolefin ring-opening polymer having a glass transition temperature of 140 to 165° C., a melt flow rate of 8 g/10 min or more as measured at a temperature of 280° C. under a load of 21.18 N, and a flexural strength of 60 MPa or more as measured by a flexural test at a test speed of 2 mm/min, and a resin formed article, and an optical member.
    Type: Application
    Filed: September 24, 2015
    Publication date: October 26, 2017
    Applicant: Zeon Corporation
    Inventors: Akira FURUKO, Takashi HOUKAWA, Ayumi SATO, Kenji UMEDA
  • Patent number: 9459376
    Abstract: An optical polymer satisfying an expression: (?A??B)/?B×100<60, where, ?A is the melt viscosity of the optical polymer measured at a temperature of 290° C. and a shear rate of 200 (l/s), and ?B is the melt viscosity of the optical polymer measured at a temperature of 290° C. and a shear rate of 2000 (l/s).
    Type: Grant
    Filed: December 17, 2013
    Date of Patent: October 4, 2016
    Assignee: ZEON CORPORATION
    Inventors: Ayumi Sato, Yosuke Harauchi, Hiroya Nishioka, Takashi Houkawa, Kenji Umeda, Takuya Komatsubara
  • Publication number: 20150346386
    Abstract: An optical polymer satisfying an expression: (?A??B)/?B×100<60, where, ?A is the melt viscosity of the optical polymer measured at a temperature of 290° C. and a shear rate of 200 (l/s), and ?B is the melt viscosity of the optical polymer measured at a temperature of 290° C. and a shear rate of 2000 (l/s).
    Type: Application
    Filed: December 17, 2013
    Publication date: December 3, 2015
    Inventors: Ayumi SATO, Yosuke HARAUCHI, Hiroya NISHIOKA, Takashi HOUKAWA, Kenji UMEDA, Takuya KOMATSUBARA
  • Patent number: 8053531
    Abstract: A hydrogenated crystalline norbornene ring-opening polymer is obtained by hydrogenating 80% or more of carbon-carbon double bonds of a ring-opening polymer that is obtained by ring-opening polymerization of norbornene monomers including 90 to 100 wt % of 2-norbornene and 0 to 10 wt % of a 2-norbornene derivative having a substituent which does not include an aliphatic carbon-carbon double bond in the presence of a branching agent, the hydrogenated crystalline norbornene ring-opening polymer having a melting point of 110 to 145° C. and a branching index of 0.3 to 0.98, and a molded article is obtained by molding the hydrogenated crystalline norbornene ring-opening polymer. The hydrogenated crystalline norbornene ring-opening polymer has excellent industrial productivity, and the molded article has excellent productivity and moisture resistance.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: November 8, 2011
    Assignee: Zeon Corporation
    Inventors: Takeshi Hirata, Takashi Houkawa, Hiroaki Matsuda, Yosuke Naka
  • Publication number: 20110021731
    Abstract: A hydrogenated crystalline norbornene ring-opening polymer is obtained by hydrogenating 80% or more of carbon-carbon double bonds of a ring-opening polymer that is obtained by ring-opening polymerization of norbornene monomers including 90 to 100 wt % of 2-norbornene and 0 to 10 wt % of a 2-norbornene derivative having a substituent which does not include an aliphatic carbon-carbon double bond in the presence of a branching agent, the hydrogenated crystalline norbornene ring-opening polymer having a melting point of 110 to 145° C. and a branching index of 0.3 to 0.98, and a molded article is obtained by molding the hydrogenated crystalline norbornene ring-opening polymer. The hydrogenated crystalline norbornene ring-opening polymer has excellent industrial productivity, and the molded article has excellent productivity and moisture resistance.
    Type: Application
    Filed: February 27, 2009
    Publication date: January 27, 2011
    Applicant: ZEON CORPORATION
    Inventors: Takeshi Hirata, Takashi Houkawa, Hiroaki Matsuda, Yosuke Naka