CARBON FIBER AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a carbon fiber which is superior to tensile modulus of elasticity and tensile strength especially, and also superior to compression modulus of elasticity and compressive strength, and to provide a manufacturing method thereof.SOLUTION: A carbon fiber contains more than 1000 carbon fiber single yarn whose surface arithmetic mean roughness Ra measured by an atomic force microscope is not more than 3.0 nm, whose crystal size of a c-axis Lc known from 002 diffraction lines by X-ray diffraction measurement is 17.0-22.4 Angstrom, and whose crystal orientationπis 83.5-85.5%, and as for the carbon fiber bundle, the degree of intermingling A is 10-80, ellipticity B of its bundle cross section is 0.15-0.40, the number of broken single yarn more than 10 mm is not more than 1.5/m, and its tensile modulus of elasticity YM is 313-345 GPa.