ACRYLONITRILE SWOLLEN YARN FOR CARBON FIBER, PRECURSOR FIBER BUNDLE, STABILIZED FIBER BUNDLE, CARBON FIBER BUNDLE, AND PRODUCTION METHODS THEREOF

摘要

Disclosed is a carbon fiber bundle for obtaining a fiber-reinforced resin having high mechanical characteristics. Specifically disclosed is an acrylonitrile swollen yarn for carbon fibers, which is not treated with an oil agent and has pores in the surface of a single fiber within a range of 0.3-2 pores/µm2 (inclusive), said pores having a width of 10 nm or more in the circumferential direction of the fiber. A precursor fiber obtained by treating the swollen yarn with a silicone oil agent has a silicon content of 1,700-5,000 ppm (inclusive), and a silicon content after 8-hour oil agent washing with methylethylketone using a Soxhlet extractor of 50-300 ppm (inclusive). The fiber is preferably composed of an acrylonitrile copolymer that contains 96.0-99.7% by mass (inclusive) of acrylonitrile and 0.3-4.0% by mass (inclusive) of an unsaturated hydrocarbon having one or more carboxyl groups or ester groups.