Abstract: A method for producing a composite material, includes: immersing a carbon fiber bundle, including continuous carbon fibers, in a dispersion in which carbon nanotubes are dispersed in water, alcohol, or organic solvent; applying a tensile force to the carbon fibers, which are linearly arranged, using flat rollers; moving the carbon fibers linearly, under the tensile force by the flat rollers, at a constant depth inside the dispersion at a traveling speed of 1 to 20 m/min, such that the carbon nanotubes in the dispersion are adhered to respective surfaces of the carbon fibers; and applying a sizing agent to cover at least a part of the respective surfaces.

Abstract: A method for producing a composite material, includes: immersing a carbon fiber bundle, including continuous carbon fibers, in a dispersion in which carbon nanotubes are dispersed in water, alcohol, or organic solvent; applying a tensile force to the carbon fibers, which are linearly arranged, using flat rollers; moving the carbon fibers linearly, under the tensile force by the flat rollers, at a constant depth inside the dispersion at a traveling speed of 1 to 20 m/min, such that the carbon nanotubes in the dispersion are adhered to respective surfaces of the carbon fibers; and applying a sizing agent to cover at least a part of the respective surfaces.

Abstract: A composite material includes: a carbon fiber bundle in which a plurality of continuous carbon fibers is arranged; carbon nanotubes which adhere to respective surfaces of the carbon fibers; and a sizing agent which covers at least a part of each of the surfaces to which the carbon nanotubes adhere. When the composite material disposed such that a longitudinal direction is vertically oriented is pierced with an inspection needle having a diameter of 0.55 mm across the longitudinal direction, and the composite material and the inspection needle are relatively moved in the longitudinal direction by 40 mm at a speed of 300 mm/min, a maximum value of a load acting between the composite material and the inspection needle is smaller than 0.5 N.