Prepreg and carbon fiber reinforced composite materials

A prepreg for a carbon fiber reinforced composite material, containing:

• carbon fiber [A];
• an epoxy resin [B] in which a thermoplastic resin is dissolved;
• thermoplastic resin particles [C];
• and
• spherical conductive particles [D] selected from the group consisting of a carbon particle, a particle having a nucleus of inorganic material that is coated with a conductive substance, and a particle having a nucleus of organic material that is coated with a conductive substance,
• wherein the carbon fiber [A] has a tensile modulus of at most 440 GPa, a tensile strength of at least 4.4 GPa and a tensile strain of at least 1.7%,
• wherein a weight ratio expressed by
• (content of [C] in parts by weight)/(content of [D] in parts by weight) is 1 to 1000,
• wherein the conductive particles [D] have an average particle diameter equal to or larger than an average particle diameter of the thermoplastic resin particles [C] and the average particle diameter is at most 150 μm,
• wherein an isomer of diaminodiphenyl sulfone is used as a hardener of the epoxy resin [B] in an equivalent ratio of the hardener to the epoxy groups contained in [B] of 0.7 to 1.0,
• wherein 90 to 100 wt % of each of the thermoplastic resin particles [C] and the conductive particles [D] is localized in a 20% depth range from both surfaces of the prepreg in the thickness direction, and
• wherein a total weight of the above-mentioned thermoplastic resin particles [C] and the above-mentioned conductive particles [D] is 1 to 20 wt % with respect to the prepreg weight.