Patents Assigned to Nippon Graphite Fiber Corporation
-
Patent number: 11059949Abstract: To provide prepreg having high thermostability and a molded body (fiber reinforced composite) obtained from the prepreg, the prepreg is formed by impregnating a reinforced fiber having an elastic modulus of 100 to 900 GPa with an epoxy resin composition including the following Components A to D so as to have a resin content within a range of 25 to 50 mass %: Component A: an epoxy resin having an oxazolidone ring structure in a molecule thereof; Component B: an epoxy resin that is liquid at 30° C.; Component C: a diblock copolymer having a B-M structure, wherein M is a block including at least 50 mass % of methyl methacrylate, B is a block immiscible with the epoxy resins and the block M, a glass transition temperature of the block B being 20° C. or lower; and Component D: dicyandiamide, or an amine curing agent that is a derivative of dicyandiamide.Type: GrantFiled: September 24, 2019Date of Patent: July 13, 2021Assignees: NIPPON STEEL CHEMICAL & MATERIAL CO., LTD., Mazda Motor Corporation, Nippon Graphite Fiber CorporationInventors: Koichi Hattori, Yutaka Arai, Masaki Shimada, Tetsuya Sugiyama, Katsuya Himuro, Masanori Honda, Kenji Nishida, Hironobu Takahama
-
Patent number: 6524501Abstract: This invention provides a pitch fiber bundle for carbon fibers of small size, a carbon fiber bundle, and a method for the production thereof, i.e. a method for the production of carbon fibers of a small size, a pitch fiber bundle, and a carbon fiber bundle at a lower cost with higher productivity than usual. The method for the production of pitch type carbon fibers according to this invention comprises dividing a plurality of pitch fibers into not less than two bundles, intertwining the bundles by exposure to currents of air thereby forming a first fiber bundle, binding a plurality of such first fiber bundles, and again intertwining the bound pitch fiber bundles by exposure to currents of air thereby forming a second fiber bundle.Type: GrantFiled: September 8, 2000Date of Patent: February 25, 2003Assignees: Nippon Steel Corporation, Nippon Mitsubishi Oil Corporation, Nippon Graphite Fiber CorporationInventors: Yutaka Arai, Yoshiyuki Doken, Tsutomu Nakamura
-
Patent number: 6273830Abstract: A tapered hollow shaft made of a fiber reinforced composite material, which comprises: (a) at least one angle layer consisting essentially of polyacrylonitrile-based carbon fibers having a tensile modulus ranging from 200 to 500 GPa and a tensile strength ranging from 4000 to 5600 MPa; (b) at least one straight layer consisting essentially of polyacrylonitrile-based carbon fibers having a tensile modulus ranging from 200 to 460 GPa and a tensile strength ranging from 3500 to 5600 MPa; (c) at least one reinforcing layer consisting essentially of pitch-based carbon fibers or polyacrylonitrile-based carbon fibers each having a compressive breaking strain of 1.7 to 5.0%, a tensile modulus ranging from 5 to 160 GPa, a tensile strength ranging from 500 to 3000 MPa and a density ranging from 1.5 to 1.Type: GrantFiled: August 27, 1999Date of Patent: August 14, 2001Assignees: Nippon Mitsubishi Oil Corporation, Nippon Steel Corporation, Nippon Steel Chemical Co., Ltd., Nippon Graphite Fiber CorporationInventors: Shinichi Takemura, Hideyuki Ohno, Tomohiro Nakanishi, Yutaka Arai, Mikio Shima
-
Patent number: 6228473Abstract: Disclosed is a plate-like carbon fiber-reinforced composite material comprising carbon fibers, wherein that the carbon fibers have a strain at compressive break of 1.7 to 5%, a tensile elastic modulus of 5 to 160 GPa, and a density of 1.5 to 1.9 g/cm3 and further in that the composite comprising said carbon fibers cause no delamination by an impact energy of less than 1.4 J/mm in the test of compression after impact in accordance with JIS K 7089.Type: GrantFiled: June 16, 1999Date of Patent: May 8, 2001Assignees: Nippon Mitsubishi Oil Corporation, Nippon Steel Corporation, Nippon Graphite Fiber CorporationInventors: Shinichi Takemura, Yoshio Soda, Hideyuki Ohno, Yutaka Arai, Tomohiro Nakanishi
-
Patent number: 6187434Abstract: This invention provides a pitch fiber bundle for carbon fibers of small size, a carbon fiber bundle, and a method for the production thereof, i.e. a method for the production of carbon fibers of a small size, a pitch fiber bundle, and a carbon fiber bundle at a lower cost with higher productivity than usual. The method for the production of pitch type carbon fibers according to this invention comprises dividing a plurality of pitch fibers into not less than two bundles, intertwining the bundles by exposure to currents of air thereby forming a first fiber bundle, binding a plurality of such first fiber bundles, and again intertwining the bound pitch fiber bundles by exposure to currents of air thereby forming a second fiber bundle.Type: GrantFiled: March 24, 2000Date of Patent: February 13, 2001Assignees: Nippon Steel Corporation, Nippon Mitsubishi Oil Corporation, Nippon Graphite Fiber CorporationInventors: Yutaka Arai, Yoshiyuki Doken, Tsutomu Nakamura
-
Patent number: 6171696Abstract: The resent invention provides a carbon fiber which enables a molded article produced from a fiber-reinforced composite material using the carbon fiber to exhibit excellent flexibility and to be freed from defects such as bending. According to the method of the present invention the carbon fiber is produced by a two-stage infusibilizing process, namely carrying out a first-stage infusibilization of a pitch-based fiber, which is obtained from mesophase pitch having a softening point of 200 to 400° C. and a true density of 1.30 to 1.38 g/cm3, in a mixed gas atmosphere having a nitrogen dioxide concentration of 1 to 5% by volume and an oxygen concentration of 5 to 50% by volume, the balance being an inert gas or steam, at a temperature between 100 and 200° C. and then carrying out a second-stage infusibilization of the product of the first-stage infusibilization in a mixed gas atmosphere having a nitrogen dioxide concentration of 0.Type: GrantFiled: May 21, 1999Date of Patent: January 9, 2001Assignees: Nippon Mitsubishi Oil Corporation, Nippon Steel Corporation, Nippon Graphite Fiber CorporationInventors: Shinichi Takemura, Yoshio Soda, Hideyuki Ohno, Yutaka Arai, Tomohiro Nakanishi
-
Patent number: 5968435Abstract: In a step of spinning a molten mesophase pitch in a process for manufacturing a pitch-type carbon fiber, the pitch is allowed to pass through an orifice and to be contracted once, is then expanded in an introduction port with a diameter greater than that of the orifice, and is then allowed to pass through an outlet pore formed at a collecting portion to spin the pitch. The pitch-type carbon fiber has a high elastic modulus in tension and high compressive strength.Type: GrantFiled: April 23, 1998Date of Patent: October 19, 1999Assignees: Nippon Steel Corporation, Nippon Steel Chemical Co., Ltd, Nippon Graphite Fiber CorporationInventors: Osamu Kato, Yoshio Kishimoto, Yutaka Arai, Hajime Nakajima, Masatoshi Furuyama, Tsutomu Kihara, Michiharu Harakawa, Shigeo Hara, Ken Kobayashi, Yoshiyuki Doken, Tsutomu Nakamura