Abstract: A method of making a carbon fiber structure including a carbon fiber is coated with a sizing at an amount X between 0.05 and 0.30 weight %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = w 0 - w 1 w 0 × 100 where W0 is a weight of the carbon fiber with the sizing, and W1 is a weight of the carbon fiber without the sizing.

Abstract: A carbon fiber fabric is made of a carbon fiber, which is coated with a sizing being formed of a heat resistant polymer or a precursor of the heat resistant polymer.

Abstract: A milled carbon fiber is made of a carbon fiber, which is coated with a sizing at an amount X between 0.05 and 0.30 weight %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = w o - w 1 w o × 100 where W0 is the weight of the carbon fiber with the sizing, and W1 is the weight of the carbon fiber without the sizing.

Abstract: A chopped carbon fiber is made of a carbon fiber, which is coated with a sizing being formed of a heat resistant polymer or a precursor of the heat resistant polymer.

Abstract: A carbon fiber braid is made of a carbon fiber, which is coated with a sizing being formed of a heat resistant polymer or a precursor of the heat resistant polymer.

Abstract: A thermoplastic molding preform is made of a carbon fiber, which is coated with a sizing at an amount X between 0.05 and 0.30 weight %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = W 0 - W 1 W 0 × 100 where W0 is the weight of the carbon fiber with the sizing, and W1 is the weight of the carbon fiber without the sizing.

Abstract: A carbon fiber is coated with a sizing at an amount X between 0.05 and 0.30 weight %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = w 0 - w 2 w 0 × 100 where W0 is a weight of the carbon fiber with the sizing, and W1 is a weight of the carbon fiber without the sizing.

Abstract: A thermoplastic resin impregnated tape is made of a carbon fiber, which is coated with a sizing at an amount X between 0.05 and 0.30 weight %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = W 0 - W 1 W 0 × 100 where W0 is the weight of the carbon fiber with the sizing, and W1 is the weight of the carbon fiber without the sizing.

Abstract: A carbon fiber is coated with a sizing at an amount X between 0.1 and 0.3 wt %. The sizing is formed of a heat resistant polymer or a precursor of the heat resistant polymer. The amount X of the sizing is expressed with a following formula: X = w 0 - w 1 w 0 × 100 where W0 is a weight of the carbon fiber with the sizing, and W1 is a weight of the carbon fiber without the sizing.

Abstract: A spinning pack for dry-wet spinning is provided with a spinneret having not less than 6,000 spinning holes and having an aspect ratio Ra of not less than 2.5 for a spinning hole array of the spinning holes. In a device and method for producing a fiber bundle, a drawing angle of single fibers formed by the single fibers and a spinneret surface of a spinneret is in a range from 87° to 92°, the single fibers being fibers discharged from the outermost spinning holes located in the long side direction of the spinneret and running to a fiber bundle diverting guide provided in a coagulation bath.

Abstract: A spinning pack for dry-wet spinning is provided with a spinneret having not less than 6,000 spinning holes and having an aspect ratio Ra of not less than 2.5 for a spinning hole array of the spinning holes. In a device and method for producing a fiber bundle, a drawing angle of single fibers formed by the single fibers and a spinneret surface of a spinneret is in a range from 87° to 92°, the single fibers being fibers discharged from the outermost spinning holes located in the long side direction of the spinneret and running to a fiber bundle diverting guide provided in a coagulation bath. Further, a drawing angle of single fibers formed by the single fibers and the spinneret surface of the spinneret is in a range from 83° to 87°, the single fibers being fibers discharged from the outermost spinning holes located in the short side direction of the spinneret and running to the fiber bundle diverting guide provided in the coagulation bath.

Abstract: Disclosed are carbon fibers consisting of a plurality of single filaments, wherein the carbon fibers as a resin impregnated strand are characterized by satisfying the following relations: &sgr;≧11.1−0.75 d where &sgr; is the tensile strength of said carbon fibers as a resin impregnated strand in GPa, and d is the average diameter of said single filaments in &mgr;m, and RD≦0.05 where RD is the difference in crystallinity between the inner and outer layers of each of the single filaments evaluated with RAMAN, and an acrylic fibers for producing the carbon fibers and a process for producing the acrylic fibers.

Abstract: Disclosed are carbon fibers consisting of a plurality of single filaments, wherein the carbon fibers as a resin impregnated strand are characterized by satisfying the following relations: &sgr;≧11.1-0.75d where &sgr; is the tensile strength of said carbon fibers as a resin impregnated strand in GPa, and d is the average diameter of said single filaments in &mgr;m, and RD≧0.05 where RD is the difference in crystallinity between the inner and outer layers of each of the single filaments evaluated with RAMAN, and an acrylic fibers for producing the carbon fibers and a process for producing the acrylic fibers.

Abstract: Disclosed are carbon fibers consisting of a plurality of single filaments, wherein the carbon fibers as a resin impregnated strand are characterized by satisfying the following relations: &sgr;≧11.1−0.75d where &sgr; is the tensile strength of said carbon fibers as a resin impregnated strand in GPa, and d is the average diameter of said single filaments in &mgr;m, and RD≦0.05 where RD is the difference in crystallinity between the inner and outer layers of each of the single filaments evaluated with RAMAN, and an acrylic fibers for producing the carbon fibers and a process for producing the acrylic fibers.

Abstract: Disclosed are carbon fibers consisting of a plurality of single filaments, wherein the carbon fibers as a resin impregnated strand are characterized by satisfying the following relations: &sgr;≧11.1−0.75 d where a is the tensile strength of said carbon fibers as a resin impregnated strand in GPa, and d is the average diameter of said single filaments in &mgr;m, and RD≦0.05 where RD is the difference in crystallinity between the inner and outer layers of each of the single filaments evaluated with RAMAN, and an acrylic fibers for producing the carbon fibers and a process for producing the acrylic fibers.

Abstract: Disclosed are carbon fibers consisting of a plurality of single filaments, wherein the carbon fibers as a resin impregnated strand are characterized by satisfying the following relations: &sgr;≧11.1−0.75 d where &sgr; is the tensile strength of said carbon fibers as a resin impregnated strand in GPa, and d is the average diameter of said single filaments in &mgr;m, and RD≦0.05 where RD is the difference in crystallinity between the inner and outer layers of each of the single filaments evaluated with RAMAN, and an acrylic fibers for producing the carbon fibers and a process for producing the acrylic fibers.

Abstract: The object of the present invention is to provide carbon fibers with high tensile strength as a resin impregnated strand even if the single filaments constituting the carbon fibers are thick. The carbon fibers of the present invention consisting of a plurality of single filaments are characterized by satisfying the following relation:.sigma..gtoreq.11.1-0.75dwhere .sigma. is the tensile strength of the carbon fibers as a resin impregnated strand (in GPa) and d is the average diameter of the single filaments (in .mu.m). The carbon fibers can be preferably used as a material for forming energy-related apparatuses such as CNG tanks, fly wheels, wind mills and turbine blades, a material for reinforcing structural members of roads, bridge piers, etc., and also a material for forming or reinforcing architectural members such as timber and curtain walls.