Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced plastic having high mechanical characteristics. An acrylonitrile swollen fiber for a carbon fiber having openings of 10 nm or more in width in the circumference direction of the swollen fiber at a ratio in the range of 0.3 openings/?m2 or more and 2 openings/?m2 or less on the surface of the swollen fiber, and the swollen fiber is not treated with a finishing oil agent. A precursor fiber obtained by treating the swollen fiber with a silicone-based finishing oil agent has a silicon content of 1700 ppm or more and 5000 ppm or less, and the silicon content is 50 ppm or more and 300 ppm or less after the finishing oil agent is washed away with methyl ethyl ketone by using a Soxhlet extraction apparatus for 8 hours. The fiber is preferably an acrylonitrile copolymer containing acrylonitrile in an amount of 96.0 mass % or more and 99.7 mass % or less and an unsaturated hydrocarbon having at least one carboxyl group or ester group in an amount of 0.

Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced resin having high mechanical characteristics. A carbon fiber bundle formed of single carbon fibers, each of which has no uneven surface structure of 0.6 ?m or more in length extending in the longitudinal direction of the single fiber; which has an uneven structure having a difference in height (Rp?v) of 5 to 25 nm between the highest portion and the lowest portion of the surface of the single fiber and having an average roughness Ra of 2 to 6 nm; and which has a ratio of the major axis to the minor axis (major axis/minor axis) of a cross-section of the single fiber of 1.00 to 1.01, wherein a mass of the single fiber per unit length falls within the range of 0.030 to 0.042 mg/m; a strand strength is 5900 MPa or more; a strand elastic modulus measured by the ASTM method is 250 to 380 GPa; and a knot tenacity is 900 N/mm2 or more.

Abstract: A phenolic-resin molding material contains a novolac-type phenolic resin, a hexamethylene tetramin, and an inorganic filler. A total content of a content of the novolac-type phenolic resin and a content of the hexamethylene tetramin is 20 to 55 mass % with respect to an entirety of the phenolic-resin molding material. A content of the inorganic filler is 45 to 80 mass % with respect to the entirety of the phenolic-resin molding material. A content of the hexamethylene tetramin is 17 to 26 pts.mass with respect to an entirety of the novolac-type phenolic resin.

Abstract: An impeller for a fuel pump is molded by a molding material containing a phenolic resin and an inorganic filler. A content at a minimum spin-spin relaxation time is 70% or higher with respect to a whole when approximating a free induction decay curve, which is obtained by Solid Echo Method in a pulse NMR measurement at 90° C., with a sum of relaxation curves of three components. The content at the minimum spin-spin relaxation time corresponds to a content of a portion of the phenolic resin, which forms the impeller for the fuel pump, where a cross-linking reaction is caused. A swelling amount of the impeller due to a liquid containing a fuel and water decreases as a crosslink density of the phenolic resin increases. The swelling amount of the impeller in the present disclosure is smaller than the swelling amount of an impeller molded by PPS resin.

Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced resin having high mechanical characteristics. A carbon fiber bundle formed of single carbon fibers, each of which has no uneven surface structure of 0.6 ?m or more in length extending in the longitudinal direction of the single fiber; which has an uneven structure having a difference in height (Rp?v) of 5 to 25 nm between the highest portion and the lowest portion of the surface of the single fiber and having an average roughness Ra of 2 to 6 nm; and which has a ratio of the major axis to the minor axis (major axis/minor axis) of a cross-section of the single fiber of 1.00 to 1.01, wherein a mass of the single fiber per unit length falls within the range of 0.030 to 0.042 mg/m; a strand strength is 5900 MPa or more; a strand elastic modulus measured by the ASTM method is 250 to 380 GPa; and a knot tenacity is 900 N/mm2 or more.

Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced plastic having high mechanical characteristics. An acrylonitrile swollen fiber for a carbon fiber having openings of 10 nm or more in width in the circumference direction of the swollen fiber at a ratio in the range of 0.3 openings/?m2 or more and 2 openings/?m2 or less on the surface of the swollen fiber, and the swollen fiber is not treated with a finishing oil agent. A precursor fiber obtained by treating the swollen fiber with a silicone-based finishing oil agent has a silicon content of 1700 ppm or more and 5000 ppm or less, and the silicon content is 50 ppm or more and 300 ppm or less after the finishing oil agent is washed away with methyl ethyl ketone by using a Soxhlet extraction apparatus for 8 hours. The fiber is preferably an acrylonitrile copolymer containing acrylonitrile in an amount of 96.0 mass % or more and 99.7 mass % or less and an unsaturated hydrocarbon having at least one carboxyl group or ester group in an amount of 0.

Abstract: This invention relates to an acrylonitrile-based precursor fiber for carbon fiber which is prepared from an acrylonitrile-based copolymer containing 96.0 to 98.5% by weight of acrylonitrile units, and which is characterized by a tensile strength of not less than 7.0 cN/dtex, an elastic modulus in tension of not less than 130 cN/dtex, an iodine adsorption of not greater than 0.5% by weight based on the weight of the fiber, a degree of crystal orientation (&pgr;) of not less than 90% as determined by wide-angle X-ray analysis, and a degree of variation in tow fineness of not greater than 1.0%. This precursor fiber has a high strength, a high elastic modulus, a high degree of denseness, a high degree of orientation, and a low degree of variation in tow fineness, and can hence be used to form a high-quality carbon fiber inexpensively by oxidation for a shorter period of time.