Abstract: A resin-integrated carbon fiber sheet 1, including: a carbon fiber sheet 2 in which a carbon fiber filament group is spread and arrayed in parallel in one direction; resin 4 that is present on part of a surface of the carbon fiber sheet; and bridging fibers 3. One or more of the bridging fibers 3 is present on average on a surface of the carbon fiber sheet 2 in a direction across the carbon fiber sheet per 10 mm2 of the sheet 2, and the resin 4 on the surface adhesively fixes the bridging fibers 3 to the carbon fiber sheet 2. Thus, the present invention provides a resin-integrated carbon fiber sheet that is strong in the width direction of the carbon fiber sheet, high in cleavage resistance and excellent in handleability, and a production method of the same.

Abstract: Fibers for fiber-reinforced resin of the present invention are fibers for fiber-reinforced resin to which a sizing agent is adhered. The fibers are at least one selected from carbon fibers and glass fibers, and an ester bond (—COO—) generated by denaturation of the sizing agent is present on surfaces of the fibers. A method for producing the same according to the present invention includes: subjecting fibers to which a sizing agent is adhered to at least one treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation at a wavelength of 400 nm or less, and a plasma treatment. The fibers are at least one selected from carbon fibers and glass fibers. Thus, it is possible to provide carbon fibers having enhanced wettability to a matrix resin and thereby allowing the matrix resin to be impregnated between the fibers easily.

Abstract: A reinforcing carbon fiber sheet (1) of the present invention includes: a carbon fiber filament (2) group arrayed in parallel in one direction; and a thermoplastic adhesive (4) present on at least part of the carbon fiber filament group in a direction across the carbon fiber filament group to unite the carbon fiber filament group. Preferably, the reinforcing sheet (1) includes a minimum amount of the carbon fibers required to produce a reinforcing effect. A sizing layer (3) of an epoxy-based resin is present on the surface of the carbon fiber filaments (2), and has a high affinity for the thermoplastic adhesive layer (4) present thereon, so that they strongly adhere to each other. Thus, the present invention provides a reinforcing carbon fiber sheet that is thin, has good handling properties and easily adheres to a substance to be reinforced.

Abstract: A method for producing a carbon fiber opened sheet 8 is provided. The method includes performing a surface activation treatment on an unopened tow of carbon fibers (3a, 3b) to which a sizing agent has been applied, and opening the unopened tow of carbon fibers (3a, 3b) into a sheet. The opening process preferably uses at least one set of opening devices. The set of opening devices includes a holding shaft (4a-4d, 5a-5d) for bending and conveying the unopened tow of carbon fibers (3a, 3b), and an opening bar (6a-6c) that vibrates in the width direction of the unopened tow. A difference in height ?H between the end of the holding shaft (4a-4d, 5a-5d) and the end of the opening bar (6a-6c) is preferably 5 to 30 mm. With this configuration, even if a sizing agent is applied to the unopened tow of carbon fibers, the filaments are easily separated from each other and the tow is easily opened. Thus, the carbon fiber opened sheet is less likely to have a defect.

Abstract: Fibers for fiber-reinforced resin of the present invention are fibers for fiber-reinforced resin to which a sizing agent is adhered. The fibers are at least one selected from carbon fibers and glass fibers, and an ester bond (—COO—) generated by denaturation of the sizing agent is present on surfaces of the fibers. A method for producing the same according to the present invention includes: subjecting fibers to which a sizing agent is adhered to at least one treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation at a wavelength of 400 nm or less, and a plasma treatment. The fibers are at least one selected from carbon fibers and glass fibers. Thus, it is possible to provide carbon fibers having enhanced wettability to a matrix resin and thereby allowing the matrix resin to be impregnated between the fibers easily.

Abstract: A reinforcing non-woven base fabric that is formed through processes in which a group of warp yarns, composed of a plurality of reinforcing fiber yarns that are aligned in a fixed direction with fixed intervals or closely, is superposed on a group of fusion-bonding multifilament yarns made of composite fibers that are aligned in a direction perpendicular to the fixed direction so that the two groups are bonded to each other through fusion-bonding, and a manufacturing method and a manufacturing machine for such a reinforcing non-woven base fabric.