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4818449 Process to prevent crack formation in the production of carbon fibers
III
New Patents
and resin precursor is heated to cure the resin precursor to bind the fibers together, removed from the mandrel, and then the resin and fugitive fibers, if any, are carbonized.
4818449 PROCESS TO PREVENT CRACK FORMATION IN THE PRODUCTION OF CARBON FIBERS Yasuhiro Yamada, Takeshi Imamura, Hidemasa Honda, Masatoshi Tsuchitani, Ryoichi Nakajima, TOSU, Japan assigned to Itaru Todorok Director-General of Agency of Indust~al Science and Technology; Maruzen Petrochemical Co Ltd When preparing carbon fibers from mesophase pitches, we usually encounter to the formation of cracks along the fiber axis. The crack formation is the most serious and troublesome problem. A simple process which can effectively prevent the crack formation comprises preparing the carbon fibers from mesophase pitches by melt spinning sufficient only to give a rotatory motion to the molten mesophase pitches just before extrusion subs~ti~ly around the axis of a spinning nozzle hole. The process employs a usual nozzle plate having a pitch introducing tube and a spinning nozzle hole further containing a plug member having an outer spiral groove such as a drill point or a worm gear which is inserted within the pitch introducing tube.
4820401 PROCESS FOR THE PREPARATION OF ~SOPHASE PITCHES Masatoshi Tsuchitani, Sakae Naito, Ryoichi Nakajima, Ichihara, Japan assigned to Iizuka Kozo; Maruzen Petrochemical Co Ltd A process for the preparation of an excellent mesophase pitch suitable for use as a spinning pitch for the production of high performance carbon fibers is disclosed. The mesophase pitch can satisfy the four remarkable characteristics at the same time, i.e., a softening point of below 320 degrees C. as determined by Mettler method, a mesophase content of above 90% as examined on a polarized microscope, a quinoline insoluble content of less than 200/ and a xylene soluble content of less than 2O*A,The mesophase pitch is particularly homogeneous and is easily spinnable. The process can be characterized by a preliminary extraction step, a continuous heat treatment step, and an extraction step. In some cases, the preliminary extraction step can be omitted. Graphite fibers having a tensile strength of about 400 Kg/mm2 and a modulus of elasticity of above 60 ton/mm2 can be obtained from the mesophase pitch. Further, even carbon fibers prepared at a carbonization temperature of 1000 degrees C. have a tensile strength of about 300 Kg/mmZ.
4822587 HIGH MOD~US Pan-BASED CARBON FIBER AND METHOD FOR PREPARING SAME
4818612 PROCESS FOR THE PRODUCTION OF PITCH-TYPE CARBON FIBERS Ryuichi Hara, Masami Kagizaki, Tsuyoshi Takakura, Shigeki Tomono, Machida, Japan assigned to Mitsubishi Chemical Industries Limited A carbon fiber having a cross-sectional crystal structure of subs~ntially u~fo~ mesh form orientation as observed by a polarizing microSCOpe.
Takashi Hino, Tsutomu Naito, Hiroyuki Kuroda, Eiki Tsushima, Tomio Nomura, Tokorozawa. Japan assigned to Toa Nenryo Kogyo Kabushiki Kaisha Extremely high modulus carbon fibers can be produced by wtion at a substantially lower temperature, for example, at about 2500 degrees C. This is made possible by selectively stabilizing only an outer surface layer portion of a carbonaceous pitch-based fiber comprised mainly of optically anisotropic components, while retaining the inner portion of the fiber in a non-stabilized state and without damage to the crystallinity thereof.
New Patents
and resin precursor is heated to cure the resin precursor to bind the fibers together, removed from the mandrel, and then the resin and fugitive fibers, if any, are carbonized.
4818449 PROCESS TO PREVENT CRACK FORMATION IN THE PRODUCTION OF CARBON FIBERS Yasuhiro Yamada, Takeshi Imamura, Hidemasa Honda, Masatoshi Tsuchitani, Ryoichi Nakajima, TOSU, Japan assigned to Itaru Todorok Director-General of Agency of Indust~al Science and Technology; Maruzen Petrochemical Co Ltd When preparing carbon fibers from mesophase pitches, we usually encounter to the formation of cracks along the fiber axis. The crack formation is the most serious and troublesome problem. A simple process which can effectively prevent the crack formation comprises preparing the carbon fibers from mesophase pitches by melt spinning sufficient only to give a rotatory motion to the molten mesophase pitches just before extrusion subs~ti~ly around the axis of a spinning nozzle hole. The process employs a usual nozzle plate having a pitch introducing tube and a spinning nozzle hole further containing a plug member having an outer spiral groove such as a drill point or a worm gear which is inserted within the pitch introducing tube.
4820401 PROCESS FOR THE PREPARATION OF ~SOPHASE PITCHES Masatoshi Tsuchitani, Sakae Naito, Ryoichi Nakajima, Ichihara, Japan assigned to Iizuka Kozo; Maruzen Petrochemical Co Ltd A process for the preparation of an excellent mesophase pitch suitable for use as a spinning pitch for the production of high performance carbon fibers is disclosed. The mesophase pitch can satisfy the four remarkable characteristics at the same time, i.e., a softening point of below 320 degrees C. as determined by Mettler method, a mesophase content of above 90% as examined on a polarized microscope, a quinoline insoluble content of less than 200/ and a xylene soluble content of less than 2O*A,The mesophase pitch is particularly homogeneous and is easily spinnable. The process can be characterized by a preliminary extraction step, a continuous heat treatment step, and an extraction step. In some cases, the preliminary extraction step can be omitted. Graphite fibers having a tensile strength of about 400 Kg/mm2 and a modulus of elasticity of above 60 ton/mm2 can be obtained from the mesophase pitch. Further, even carbon fibers prepared at a carbonization temperature of 1000 degrees C. have a tensile strength of about 300 Kg/mmZ.
4822587 HIGH MOD~US Pan-BASED CARBON FIBER AND METHOD FOR PREPARING SAME
4818612 PROCESS FOR THE PRODUCTION OF PITCH-TYPE CARBON FIBERS Ryuichi Hara, Masami Kagizaki, Tsuyoshi Takakura, Shigeki Tomono, Machida, Japan assigned to Mitsubishi Chemical Industries Limited A carbon fiber having a cross-sectional crystal structure of subs~ntially u~fo~ mesh form orientation as observed by a polarizing microSCOpe.
Takashi Hino, Tsutomu Naito, Hiroyuki Kuroda, Eiki Tsushima, Tomio Nomura, Tokorozawa. Japan assigned to Toa Nenryo Kogyo Kabushiki Kaisha Extremely high modulus carbon fibers can be produced by wtion at a substantially lower temperature, for example, at about 2500 degrees C. This is made possible by selectively stabilizing only an outer surface layer portion of a carbonaceous pitch-based fiber comprised mainly of optically anisotropic components, while retaining the inner portion of the fiber in a non-stabilized state and without damage to the crystallinity thereof.