Patents by Inventor Norifumi Hirota
Norifumi Hirota 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).
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Patent number: 11959197Abstract: A first aspect of the present invention is carbon fiber wherein the surface of a monofilament has a center line average roughness Ra of 6.0 nm or more and 13 nm or less, and the monofilament has a long diameter/short diameter ratio of 1.11 or more and 1.245 or less. A second aspect of the present invention is carbon fiber precursor acrylic fiber wherein the surface of a monofilament has a center line average roughness Ra of 18 nm or more and 27 nm or less, and the monofilament has a long diameter/short diameter ratio of 1.11 or more and 1.245 or less. The carbon fiber according to the first aspect is obtained by stabilizing and carbonizing under specific conditions the carbon fiber precursor acrylic fiber according to the second aspect.Type: GrantFiled: August 15, 2019Date of Patent: April 16, 2024Assignee: Mitsubishi Chemical CorporationInventors: Naomasa Matsuyama, Yuutarou Nakamura, Norifumi Hirota, Hiroko Matsumura, Katsuhiko Ikeda, Kouki Wakabayashi, Tadashi Ootani, Akihiro Itou, Kenji Hirano, Akito Hatayama, Kenji Kaneta, Atsushi Nakajima
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Patent number: 11332852Abstract: A method of producing a carbon fiber bundle is provided, involving performing a flame-proof treatment to a carbon-fiber-precursor acryl fiber bundle having a single-fiber fineness of 1.5 dtex or more and 5.0 dtex or less, and having a roundness of 0.7 or more and 0.9 or less in a cross-section shape perpendicular to a fiber axis of the single fiber to obtain a flame-proofed fiber bundle; and performing a carbonization treatment to the flame-proofed fiber bundle.Type: GrantFiled: April 28, 2020Date of Patent: May 17, 2022Assignee: Mitsubishi Chemical CorporationInventors: Yuusuke Shinmen, Norifumi Hirota, Takeshi Nii
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Publication number: 20200263327Abstract: Provided are: a carbon fiber bundle which has a large value of single-fiber fineness and excellent productivity and which, despite this, contains few interlaced single fibers therein and has excellent spreadability; and precursor fibers which are suitable for use in producing the carbon fiber bundle. The precursor fibers are a carbon-fiber-precursor acrylic fiber bundle which comprises a polyacrylonitrile copolymer comprising 95-99 mol % acrylonitrile units and 1-5 mol % hydroxyalkyl (meth)acrylate units and which has a single-fiber fineness of 1.5-5.0 dtex. In the acrylic fiber bundle, the cross-section of each single fiber which is perpendicular to the fiber axis has a shape that has a roundness of 0.9 or less.Type: ApplicationFiled: April 28, 2020Publication date: August 20, 2020Applicant: Mitsubishi Chemical CorporationInventors: Yuusuke Shinmen, Norifumi Hirota, Takeshi Nii
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Patent number: 10662556Abstract: A carbon fiber bundle, wherein an average single-fiber fineness is from 1.0 to 2.4 dtex and a roundness is from 0.7 to 0.9 in a shape of a cross-section perpendicular to a fiber axis of a single fiber; the roundness being determined with equation (1): roundness=4?S/L2, where S is a cross-sectional area of the single fiber and L is a circumferential length of the single fiber, and S and L are obtained by observing, under an SEM, the cross-section of the single fiber perpendicular to the fiber axis of the single fiber and analyzing the obtained image.Type: GrantFiled: January 28, 2019Date of Patent: May 26, 2020Assignee: Mitsubishi Chemical CorporationInventors: Yuusuke Shinmen, Norifumi Hirota, Takeshi Nii
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Publication number: 20200002850Abstract: A first aspect of the present invention is carbon fiber wherein the surface of a monofilament has a center line average roughness Ra of 6.0 nm or more and 13 nm or less, and the monofilament has a long diameter/short diameter ratio of 1.11 or more and 1.245 or less. A second aspect of the present invention is carbon fiber precursor acrylic fiber wherein the surface of a monofilament has a center line average roughness Ra of 18 nm or more and 27 nm or less, and the monofilament has a long diameter/short diameter ratio of 1.11 or more and 1.245 or less. The carbon fiber according to the first aspect is obtained by stabilizing and carbonizing under specific conditions the carbon fiber precursor acrylic fiber according to the second aspect.Type: ApplicationFiled: August 15, 2019Publication date: January 2, 2020Applicant: Mitsubishi Chemical CorporationInventors: Naomasa Matsuyama, Yuutarou Nakamura, Norifumi Hirota, Hiroko Matsumura, Katsuhiko Ikeda, Kouki Wakabayashi, Tadashi Ootani, Akihiro Itou, Kenji Hirano, Akito Hatayama, Kenji Kaneta, Atsushi Nakajima
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Publication number: 20190153628Abstract: A carbon fiber bundle, wherein an average single-fiber fineness is from 1.0 to 2.4 dtex and a roundness is from 0.7 to 0.9 in a shape of a cross-section perpendicular to a fiber axis of a single fiber; the roundness being determined with equation (1): roundness=4?S/L2, where S is a cross-sectional area of the single fiber and L is a circumferential length of the single fiber, and S and L are obtained by observing, under an SEM, the cross-section of the single fiber perpendicular to the fiber axis of the single fiber and analyzing the obtained image.Type: ApplicationFiled: January 28, 2019Publication date: May 23, 2019Applicant: Mitsubishi Chemical CorporationInventors: Yuusuke SHINMEN, Norifumi HIROTA, Takeshi NII
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Patent number: 10233569Abstract: A carbon fiber bundle, wherein an average single-fiber fineness is from 1.0 to 2.4 dtex and a roundness is from 0.7 to 0.9 in a shape of a cross-section perpendicular to a fiber axis of a single fiber; the roundness being determined with equation (1): roundness=4?S/L2, where S is a cross-sectional area of the single fiber and L is a circumferential length of the single fiber, and S and L are obtained by observing, under an SEM, the cross-section of the single fiber perpendicular to the fiber axis of the single fiber and analyzing the obtained image.Type: GrantFiled: February 5, 2018Date of Patent: March 19, 2019Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yuusuke Shinmen, Norifumi Hirota, Takeshi Nii
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Patent number: 10017881Abstract: Provided are: a polyacrylonitrile-based precursor fiber for the production of a carbon fiber having a large single-fiber fineness, said precursor fiber ensuring high heat stability of a spinning dope and excellent productivity; and a copolymer suitable for the production of said precursor fiber. Also provided are: high-quality carbon fiber bundles which have a large single-fiber fineness and excellent productivity; a process for producing the same; and a process for producing flameproofed fiber bundles suitable for the production of the carbon fiber bundles. A polyacrylonitrile-based copolymer which comprises 93.0 to 99.4 mol % of acrylonitrile units, 0.5 to 4.0 mol % of (meth)acrylamide-based units, and 0.1 to 3.Type: GrantFiled: July 20, 2012Date of Patent: July 10, 2018Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yusuke Shinmen, Norifumi Hirota, Naoki Aoyama, Naomasa Matsuyama, Takeshi Nii, Yasuyuki Fujii, Yoshiko Irie, Harumi Matsuda
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Publication number: 20180155855Abstract: A carbon fiber bundle, wherein an average single-fiber fineness is from 1.0 to 2.4 dtex and a roundness is from 0.7 to 0.9 in a shape of a cross-section perpendicular to a fiber axis of a single fiber; the roundness being determined with equation (1): roundness=4?S/L2, where S is a cross-sectional area of the single fiber and L is a circumferential length of the single fiber, and S and L are obtained by observing, under an SEM, the cross-section of the single fiber perpendicular to the fiber axis of the single fiber and analyzing the obtained image.Type: ApplicationFiled: February 5, 2018Publication date: June 7, 2018Applicant: Mitsubishi Chemical CorporationInventors: Yuusuke SHINMEN, Norifumi HIROTA, Takeshi NII
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Patent number: 9920456Abstract: A carbon-fiber-precursor acryl fiber bundle, including a polyacrylonitrile-based copolymer that contains from 95 to 99 mol % of an acrylonitrile unit and from 1 to 5 mol % of a hydroxyalkyl (meth)acrylate unit, where the fiber bundle has a single-fiber fineness of from 1.5 dtex to 5.0 dtex and a roundness of from 0.75 to 0.9 in a cross-section shape perpendicular to a fiber axis of the single fiber; the roundness being determined with equation (1): roundness=4?S/L2, where S is a cross-sectional area of the single fiber and L is a circumferential length of the single fiber, and S and L are obtained by observing, under an SEM, the cross-section of the single fiber perpendicular to the fiber axis of the single fiber and analyzing the obtained image.Type: GrantFiled: October 13, 2011Date of Patent: March 20, 2018Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yuusuke Shinmen, Norifumi Hirota, Takeshi Nii
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Publication number: 20140212663Abstract: Provided are: a polyacrylonitrile-based precursor fiber for the production of a carbon fiber having a large single-fiber fineness, said precursor fiber ensuring high heat stability of a spinning dope and excellent productivity; and a copolymer suitable for the production of said precursor fiber. Also provided are: high-quality carbon fiber bundles which have a large single-fiber fineness and excellent productivity; a process for producing the same; and a process for producing flameproofed fiber bundles suitable for the production of the carbon fiber bundles. A polyacrylonitrile-based copolymer which comprises 93.0 to 99.4 mol % of acrylonitrile units, 0.5 to 4.0 mol % of (meth)acrylamide-based units, and 0.1 to 3.Type: ApplicationFiled: July 20, 2012Publication date: July 31, 2014Applicant: MITSUBISHI RAYON CO., LTD.Inventors: Yusuke Shinmen, Norifumi Hirota, Naoki Aoyama, Naomasa Matsuyama, Takeshi Nii, Yasuyuki Fujii, Yoshiko Irie, Harumi Matsuda
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Publication number: 20130295811Abstract: Provided are: a carbon fiber bundle which has a large value of single-fiber fineness and excellent productivity and which, despite this, contains few interlaced single fibers therein and has excellent spreadability; and precursor fibers which are suitable for use in producing the carbon fiber bundle. The precursor fibers are a carbon-fiber-precursor acrylic fiber bundle which comprises a polyacrylonitrile copolymer comprising 95-99 mol % acrylonitrile units and 1-5 mol % hydroxyalkyl (meth)acrylate units and which has a single-fiber fineness of 1.5-5.0 dtex. In the acrylic fiber bundle, the cross-section of each single fiber which is perpendicular to the fiber axis has a shape that has a roundness of 0.9 or less.Type: ApplicationFiled: October 13, 2011Publication date: November 7, 2013Applicant: MITSUBISHI RAYON CO., LTD.Inventors: Yuusuke Shinmen, Norifumi Hirota, Atsushi Nakajima, Naoki Aoyama, Naomasa Matsuyama, Takeshi Nii, Akiyoshi Kogame, Yasuyuki Fujii, Yoshiko Irie, Harumi Matsuda, Takayuki Kiriyama, Teppei Miura, Takuya Teranishi, Shouhei Mori, Manabu Kaneko, Kiharu Numata, Masahiro Ichino, Shigekazu Takeda, Takayuki Kobayashi, Toshiyuki Itou, Masahiro Hata, Hiroyuki Nakao, Kenichi Watanabe
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Patent number: 8569408Abstract: Disclosed are an acrylonitrile copolymer excellent in thermal stability as a solution (spinning dope) when dissolved in an amide solvent and capable of forming dense polyacrylonitrile fiber suitable for production of carbon fiber, an acrylonitrile copolymer solution in which the acrylonitrile copolymer is dissolved in an amide solvent, and a method for producing polyacrylonitrile precursor fiber for carbon fiber by use of the acrylonitrile copolymer solution. Specifically, an acrylonitrile copolymer contains a sulfonate group derived from a polymerization initiator in an amount of 1.0×10?5 equivalent/g or more, and the value (equivalent ratio) of (the content of a sulfate group derived from the polymerization initiator/the total content of the sulfonate group and the sulfate group) is 0.4 or less; an acrylonitrile copolymer solution contains the aforementioned acrylonitrile copolymer and an amide solvent.Type: GrantFiled: May 12, 2009Date of Patent: October 29, 2013Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Norifumi Hirota, Yusuke Shinmen, Naomasa Matsuyama, Takeshi Nii, Harumi Shibatani
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Publication number: 20110130503Abstract: Disclosed are an acrylonitrile copolymer excellent in thermal stability as a solution (spinning dope) when dissolved in an amide solvent and capable of forming dense polyacrylonitrile fiber suitable for production of carbon fiber, an acrylonitrile copolymer solution in which the acrylonitrile copolymer is dissolved in an amide solvent, and a method for producing polyacrylonitrile precursor fiber for carbon fiber by use of the acrylonitrile copolymer solution. Specifically, an acrylonitrile copolymer contains a sulfonate group derived from a polymerization initiator in an amount of 1.0×10?5 equivalent/g or more, and the value (equivalent ratio) of (the content of a sulfate group derived from the polymerization initiator/the total content of the sulfonate group and the sulfate group) is 0.4 or less; an acrylonitrile copolymer solution contains the aforementioned acrylonitrile copolymer and an amide solvent.Type: ApplicationFiled: May 12, 2009Publication date: June 2, 2011Applicant: Mitsubishi Rayon Co., Ltd.Inventors: Norifumi Hirota, Yusuke Shinmen, Naomasa Matsuyama, Takeshi Nii, Harumi Shibatani
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Patent number: 7777964Abstract: A plastic rod lens having a cylindrical shape with a radius R including a central axis; and an outer peripheral portion, wherein a refractive index nD decreases from the central axis to the outer peripheral portion, and the following requirements (1) to (3) are met: 43??1?60??(1) |{nA×?A/(nA?1)}?{nB×?B/(nB?1)}|<5??(2) n0?n1?0.01??(3) wherein n1, n0, nA, and nB represent refraction index nD in the outer peripheral portion, at the center, and at arbitrary points A and B, respectively, and ?1, ?A, and ?B represent Abbe number ? in the outer peripheral portion, and at the arbitrary points A and B, respectively.Type: GrantFiled: July 21, 2006Date of Patent: August 17, 2010Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Hiroshi Abe, Takashi Saeki, Tsuyoshi Nakagawa, Norifumi Hirota
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Publication number: 20090257128Abstract: A plastic rod lens having a cylindrical shape with a radius R including a central axis; and an outer peripheral portion, wherein a refractive index nD decreases from the central axis to the outer peripheral portion, and the following requirements (1) to (3) are met: 43??1?60??(1) |{nA×?A/(nA?1)}?{nB×?B/(nB?1)}|<5??(2) n0?n1?0.01??(3) wherein n1, n0, nA, and nB represent refraction index nD in the outer peripheral portion, at the center, and at arbitrary points A and B, respectively, and ?1, ?A, and ?B represent Abbe number ? in the outer peripheral portion, and at the arbitrary points A and B, respectively.Type: ApplicationFiled: July 21, 2006Publication date: October 15, 2009Applicant: Mitsubishi Rayon Co., Ltd.Inventors: Hiroshi Abe, Takashi Saeki, Tsuyoshi Nakagawa, Norifumi Hirota
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Patent number: 7043113Abstract: Disclosed is an optical multi/demultiplexer, which comprises a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof, a wavelength-multiplexed-light connecting section disposed at one of the axial ends of the light transmission section, and at least one monochromatic light connecting section disposed at the other axial end of the light transmission section. The wavelength-multiplexed-light connecting section and the monochromatic light connecting section are disposed relative to the light transmission section in such a positional relationship that a monochromatic light included in a wavelength multiplexed light entered from the wavelength-multiplexed-light connecting section into the one end of the light transmission section is emitted from the other end of the light transmission section at a position where the monochromatic light connecting section is disposed.Type: GrantFiled: April 30, 2004Date of Patent: May 9, 2006Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Toshiaki Hattori, Norifumi Hirota, Yoshihiro Uozu
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Publication number: 20050094935Abstract: Disclosed is an optical multi/demultiplexer, which comprises a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof, a wavelength-multiplexed-light connecting section disposed at one of the axial ends of the light transmission section, and at least one monochromatic light connecting section disposed at the other axial end of the light transmission section. The wavelength-multiplexed-light connecting section and the monochromatic light connecting section are disposed relative to the light transmission section in such a positional relationship that a monochromatic light included in a wavelength multiplexed light entered from the wavelength-multiplexed-light connecting section into the one end of the light transmission section is emitted from the other end of the light transmission section at a position where the monochromatic light connecting section is disposed.Type: ApplicationFiled: November 24, 2004Publication date: May 5, 2005Applicant: Mitsubishi Rayon Co., Ltd.Inventors: Toshiaki Hattori, Norifumi Hirota, Yoshihiro Uozu
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Publication number: 20040202409Abstract: Disclosed is an optical multi/demultiplexer, which comprises a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof, a wavelength-multiplexed-light connecting section disposed at one of the axial ends of the light transmission section, and at least one monochromatic light connecting section disposed at the other axial end of the light transmission section. The wavelength-multiplexed-light connecting section and the monochromatic light connecting section are disposed relative to the light transmission section in such a positional relationship that a monochromatic light included in a wavelength multiplexed light entered from the wavelength-multiplexed-light connecting section into the one end of the light transmission section is emitted from the other end of the light transmission section at a position where the monochromatic light connecting section is disposed.Type: ApplicationFiled: April 30, 2004Publication date: October 14, 2004Applicant: Mitsubishi Rayon Co., Ltd.Inventors: Toshiaki Hattori, Norifumi Hirota, Yoshihiro Uozu
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Patent number: 6654173Abstract: An object of this invention is to provide a lens array in which the amount of light reaching the image forming surface is large and the variation in the amount of light is small. In order to achieve this object, the lens array comprises cylindrical graded index lenses of radius r0 wherein the refractive index continuously decreases from the center of the lens toward the periphery, said cylindrical graded index lenses are arranged in one line or plural lines with array pitch 2R, if R is R≧r0≧0.8R and if the refractive index profile of each graded index lens is approximated by n(r)2=n02{1−(g·r)2}, the overlapping degree m defined by m=X0/2R satisfies 1.05≦m≦1.Type: GrantFiled: April 25, 2002Date of Patent: November 25, 2003Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Yoshihiro Uozu, Norifumi Hirota, Toshinori Sumi, Teruta Ishimaru