Carbon fibers coated with a bonding agent, process for production of the carbon fibre prepreg and composite material reinforced with carbon fibers

摘要

Provided are sizing agent-coated carbon fibers that achieve excellent adhesion between the carbon fibers and a matrix resin and yield a prepreg having excellent stability of composite physical properties after long-term storage and having excellent high-order processability, a process for producing the sizing agent-coated carbon fibers, a prepreg, and a carbon fiber reinforced composite material. The present invention provides carbon fibers coated with a sizing agent that includes an aliphatic epoxy compound (A) and at least an aromatic epoxy compound (B1) as an aromatic compound (B). The carbon fibers have an (a)/(b) ratio of 0.50 to 0.90 where (a) is the height (cps) of a component at a binding energy (284.6 eV) assigned to CHx, C-C, and C=C and (b) is the height (cps) of a component at a binding energy (286.1 eV) assigned to C-O in a C 1s core spectrum of the surface of the sizing agent analyzed by X-ray photoelectron spectroscopy using AlK± 1,2 as the X-ray source at a photoelectron takeoff angle of 15°.