Abstract: A pressure vessel including: a cylindrical straight body section and dome sections provided at both ends of the body section, where: the body section and the dome sections are composed of a resin main body, and an outer shell made of a fiber reinforced resin material, the outer shell being on the outside of the main body; each of dome sections has pinch-off regions extending from a tip of the dome section toward the body section; and when an end of each of the pinch-off regions opposite to the tip of the dome section is located in a region where a distance from the tip of the dome section to the end of each of the pinch-off regions opposite to the tip of the dome section in the axial direction of the straight body section is less than a distance from the tip of each of the dome sections to a boundary between the straight body section of the main body and each of the dome sections in the axial direction of the straight body section.

Abstract: An object of the present invention is to provide a pressure vessel that is light in weight and has a sufficient internal capacity as well as excellent durability.

Abstract: A pressure vessel comprises a liner formed by blow-molding; an FRP layer covers the outer surface of the liner; and a stock comprising a stock main body, formed from metal with a cylindrical section passing through the liner and FRP layer and a circular metal flange section projecting outward from one end of the cylindrical section in the radial direction of the cylindrical section, and a molded piece, formed of a synthetic resin, covers at least the outer circumferential surface of the cylindrical section and all the metal flange section of the stock main body, has a circular resin flange section projecting outward from the edge of the metal flange section that faces outward in the radial direction, and adheres to the inner surface of the liner. The resin flange section comprises an upper surface, an outer circumferential edge surface and a lower surface.

Abstract: A pressure vessel comprises a liner formed by blow-molding; an FRP layer covers the outer surface of the liner; and a stock comprising a stock main body, formed from metal with a cylindrical section passing through the liner and FRP layer and a circular metal flange section projecting outward from one end of the cylindrical section in the radial direction of the cylindrical section, and a molded piece, formed of a synthetic resin, covers at least the outer circumferential surface of the cylindrical section and all the metal flange section of the stock main body, has a circular resin flange section projecting outward from the edge of the metal flange section that faces outward in the radial direction, and adheres to the inner surface of the liner. The resin flange section comprises an upper surface, an outer circumferential edge surface and a lower surface.

Abstract: A short carbon fiber bundling mass is disclosed, which can provide a high-modulus fiber-reinforced resin composition and comprises short carbon fibers bundled by using a sizing agent and heated to a maximum temperature ranging from 1,600° C. to 3,300° C. in an inert gas atmosphere so as to be graphitized.

Abstract: A short carbon fiber bundling mass is disclosed, which can provide a high-modulus fiber-reinforced resin composition and comprises short carbon fibers bundled by using a sizing agent and heated to a maximum temperature ranging from 1,600.degree. C. to 3,300.degree. C. in an inert gas atmosphere so as to be graphitized.