| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a dense polyacrylonitrile (PAN)-based carbon fiber having high orientation, high strength and high modulus. SOLUTION: A carbonizing step for carbonizing a PAN-based flame-proofed fiber is constituted of the first carbonizing step, the second carbonizing step and the third carbonizing step. The third carbonizing step is separated to the primary treatment and the secondary treatment, and the specific resistance value, the specific gravity, the N/C, the single fiber elongation and the crystal size by a wide angle x-ray measurement (at 26°diffraction angle) of the fiber, and the temperature and the draw ratio are regulated in each treatment. The fiber tension is regulated within the range satisfying the expression using a fiber stress (D or E, mN) expressed per fiber cross section because the fiber tension is changed according to the fiber diameter, i.e. the fiber cross section (S, mm<SP>2</SP>). COPYRIGHT: (C)2007,JPO&INPIT
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