To provide a method for efficiently producing a carbon fiber, preferably, an ultra-fine carbon fiber, and to provide the ultra-fine carbon fiber excellent in mechanical characteristics and having a fiber diameter of 0.001-5 μm.
This method for producing the carbon fiber comprises processes (1) to (4) as follows: (1) a thermoplastic resin in an amount of 100pts.wt. is mixed with at least one kind of carbon precursor organic compound (A) selected from the group consisting of pitch, polyarylonitrile, cellulose, and polycarbodiimide in an amount of 1-150pts.wt., then the mixture is spun to produce a carbon fiber precursor (B); (2) the carbon fiber precursor organic compound (A) contained in the carbon fiber precursor (B) is subjected to stabilization treatment to produce a carbon fiber stabilized precursor (C); (3) the thermoplastic resin contained in the carbon fiber stabilized precursor (C) is removed; and (4) the carbon fiber stabilized precursor from which the thermoplastic resin is removed (D) is carbonized or graphitized to produce the carbon fiber.
SAKURAI HIROSHI
SAWAKI TORU
