| 摘要 |
PROBLEM TO BE SOLVED: To obtain a prepreg having excellent moldability to form a composite material and mechanical properties by applying fine particles having specific particle diameter and a sizing agent to a specific carbon fiber. SOLUTION: Fine particles having particle diameter of <=0.01μm and <=5μm and consisting of inorganic fine particles such as aluminum silicate, magnesium silicate or graphite, organic fine particles such as polyester, polyamide or polyvinyl chloride, etc., or their mixture are compounded with a sizing agent consisting of a polyalkylene glycol, a polyurethane, a vinyl ester, a saturated polyester, a poly(amide)imide, etc., or their mixture to obtain an aqueous dispersion. The aqueous dispersion is impregnated in a carbon fiber consisting of a bundle of >=12,000 single fibers and having a specific surface oxygen concentration (0/C) of >=0.02 and <=0.2 and a specific surface nitrogen concentration (O/C)of >=0.02 and <=0.3 measured by an X-ray photoelectron spectroscopy to obtain a carbon fiber containing >=0.05 wt.% and <=5wt.% of the fine particles and >=0.1wt.% and <=5wt.% of the sizing agent. A prepreg is produced from the obtained carbon fiber. |
