| 摘要 |
PROBLEM TO BE SOLVED: To obtain chopped carbon fibers excellent in handling properties such as flowability and bindability by imparting an aqueous dispersion type sizing agent to a continuous carbon yarn bundle, cutting the bundle in a wet state, and subsequently drying the cut bundle under vibration. SOLUTION: The chopped carbon fibers are obtained by imparting a treating solution comprising an aqueous dispersion sizing agent containing one or the mixture of a urethane resin, an acrylic resin and an epoxy resin as a main component to a continuous carbon filament bundle comprising 20,000-150,000 filaments, controlling the treated bundle to a packing density of 5,000-20,000 D/mm, cutting the controlled bundle in a prescribed length in a wet state, and subsequently drying the cut bundle. The obtained chopped carbon fibers have an average weight of 1.7-4 mg/mm of a longitudinal unit length of the staple fiber bundle, a weight distribution variation rate of 30-60%, and an approximately rectangular staple fiber bundle cross-section shape whose one side has a length distribution having an average value of 1.5-6 mm and a variation degree of 25-40%. |
