Carbon fiber bundle, and carbon fiber-reinforced composite material using same

A carbon fiber bundle comprising a sizing agent added thereto, wherein the tensile strength of resin-impregnated strands (tensile strength A′ of resin-impregnated strands) of the carbon fiber bundle is 5.0 GPa or more and 6.0 GPa or less, as evaluated on the basis of JIS R7608 (2007) using Resin Formulation A below;

• wherein the tensile strength of resin-impregnated strands (tensile strength B′ of resin-impregnated strands) of the carbon fiber bundle is 4.7 GPa or more and 5.5 GPa or less, as evaluated on the basis of JIS R7608 (2007) using Resin Formulation B below;
• wherein the ratio of the tensile strength B′ of resin-impregnated strands to the tensile strength A′ of resin-impregnated strands is 85% or more;
• and wherein the single-fiber diameter of the carbon fiber bundle is 6.0 μm or more;
• Resin Formulation A:
• “CELLOXIDE (registered trademark)” 2021P, boron trifluoride monoethyl amine, and acetone are used at a ratio of 100:3:4 (parts by mass), and the curing conditions of a normal pressure, a temperature of 125° C., and a time of 30 minutes are used;
• and
• Resin Formulation B:
• “JER (registered trademark)” 828, dicyandiamide, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea are used at a ratio of 100:6.3:2 (parts by mass), and the curing conditions of a normal pressure, a temperature of 130° C., and a time of 90 minutes are used.