Abstract: Provided is a prepreg including: a fiber layer containing unidirectionally arranged carbon fibers impregnated with a first thermosetting resin; and a resin layer disposed on at least one side of the fiber layer and containing a second thermosetting resin and a thermoplastic resin that is insoluble in the second thermosetting resin. The prepreg is configured such that the areal weight of fibers and the weight fraction of resin in the prepreg are 120 to 300 g/m2 and 25 to 50 mass %, respectively, and in the case where a plurality of prepregs are laid up, and the coefficient of interlayer friction is measured every 10° C. in a temperature range of 40 to 100° C. at a pull-out speed of 0.2 mm/min under a perpendicular stress of 0.8 bar, the temperature at which the coefficient of interlayer friction is 0.02 or less is present within a temperature range of 40 to 100° C.

Abstract: Provided is a prepreg including: a fiber layer containing unidirectionally arranged carbon fibers impregnated with a first thermosetting resin; and a resin layer disposed on at least one side of the fiber layer and containing a second thermosetting resin and a thermoplastic resin that is insoluble in the second thermosetting resin. The prepreg is configured such that the areal weight of fibers and the weight fraction of resin in the prepreg are 120 to 300 g/m2 and 25 to 50 mass %, respectively, and in the case where a plurality of prepregs are laid up, and the coefficient of interlayer friction is measured every 10° C. in a temperature range of 40 to 100° C. at a pull-out speed of 0.2 mm/min under a perpendicular stress of 0.8 bar, the temperature at which the coefficient of interlayer friction is 0.02 or less is present within a temperature range of 40 to 100° C.

Abstract: An intermediate base material has high handleability and shape conformity to complicated shapes and serves to perform high-yield production, even by low pressure molding, of fiber reinforced plastic material that do not suffer from significant generation of molding defects, such as creases and voids, that can cause a decrease in strength and that has good mechanical characteristics, decreased variations therein, and high dimensional stability. The prepreg includes a layer containing reinforcement fibers impregnated with a resin composition and the impregnation rate with the resin composition in the prepreg is in a predetermined range. It is characterized by being an incised prepreg having a plurality of incisions, being at least partly formed of reinforcement fibers with a predetermined fiber length, and having a reinforcement fiber content by volume Vf in a predetermined range.

Abstract: A process is capable of producing a high-quality fiber-reinforced plastic with good yield in a short molding cycle time despite being atmospheric pressure molding. The process characterized uses local contact heating to give different temperature conditions to produce a fiber-reinforced plastic by atmospheric pressure molding from a fiber-reinforced material which contains a reinforcing fiber impregnated with a thermosetting resin composition.

Abstract: A composite prepreg base includes a raw prepreg base comprising a fiber sheet including discontinuous reinforcing fibers arranged in one direction and having a fiber length of 1-300 mm and a matrix resin infiltrated into the fiber sheet; and an additional resin layer formed on at least one surface of the raw prepreg base. The composite prepreg base is produced by a process including (i) the step of preparing the raw prepreg base and (ii) the step of forming an additional resin layer on at least one surface of the raw prepreg base prepared. A layered base includes two or more sheets of the composite prepreg base which have been superposed so that the additional resin layer is present on at least one surface; and a fiber-reinforced plastic formed by heating and pressing the layered base.

Abstract: A laminated base material includes a lamination and integration of prepreg base materials each of which includes many reinforcing fibers arranged substantially in one direction and a matrix resin adhered to the reinforcing fibers, wherein at least one of the laminated prepreg base materials is formed with a prepreg base material having, throughout its whole surface, many incisions each extending in a direction crossing the reinforcing fibers, substantially all of the reinforcing fibers divided by incisions, and wherein a length L of each of reinforcing fiber segments formed by the incisions is 10 to 100 mm, a thickness H of the prepreg base material is 30 to 300 ?m, and a fiber volume content Vf of the reinforcing fibers is 45 to 65% and arranging directions of the reinforcing fibers between one and another laminated prepreg base materials have at least two directions different each other.

Abstract: A composite prepreg base which includes a raw prepreg base comprising a fiber sheet comprising discontinuous reinforcing fibers arranged in one direction and having a fiber length of 1-300 mm and a matrix resin infiltrated into the fiber sheet; and an additional resin layer formed on at least one surface of the raw prepreg base. The composite prepreg base is produced by a process including (i) the step of preparing the raw prepreg base and (ii) the step of forming an additional resin layer on at least one surface of the raw prepreg base prepared. Also provided are: a layered base including two or more sheets of the composite prepreg base which have been superposed so that the additional resin layer is present on at least one surface; and a fiber-reinforced plastic formed by heating and pressing the layered base.

Abstract: A prepreg base material includes reinforcing fibers arranged substantially in one direction and a matrix resin between the reinforcing fibers, wherein the prepreg base material has substantially throughout its entire surface incisions, each incision extending in a direction substantially crossing the reinforcing fibers, wherein substantially all of the reinforcing fibers are divided by the incisions, a length (L) of each of reinforcing fiber segments formed by the incisions is in the range of 10 to 100 mm, a thickness H of the prepreg base material is in the range of 30 to 300 ?m, and a fiber volume content by Vf of the reinforcing fibers is in the range of 45 to 65%.

Abstract: A chopped fiber bundle includes a large number of unidirectionally arranged reinforced fibers. The length of each of the reinforced fibers is in the range of 5 to 100 mm. The chopped fiber bundle has a transition segment in which the number of the reinforced fibers increases toward the central part of the chopped fiber bundle in the aligned direction of the reinforced fibers with both ends in the aligned of the reinforced fibers in the chopped fiber bundle being a starting point. The level of a change in total sectional area of the large number of reinforced fibers is not more than 0.05 mm2 per mm in the aligned direction of the reinforced fibers over the whole area in the longitudinal direction of the chopped fiber bundle.

Abstract: A fiber-reinforced plate-like plastic having a plate and a protrusion rising on the plate, wherein the plate and the protrusion each contain a laminated structure composed of plural reinforcing fiber sheets which each include many fibers of 10 to 100 mm in fiber length arranged in a fixed direction and at least two of the layers constituting the laminated structure are different in the direction of arrangement of reinforcing fibers and wherein at least part of the reinforcing fibers extend continuously from the plate to the protrusion and at least one of the layers constituting the laminated structure of the protrusion has a shape similar to the shape of the protrusion; and a process for the production of fiber-reinforced plastic which includes cutting a unidirectional prepreg sheet composed of many reinforcing fibers arranged in a fixed direction and a matrix resin into prepreg base material sheets with the above fiber length, laminating the prepreg base material sheets with the directions of arrangement of

Abstract: A chopped fiber bundle includes a large number of unidirectionally arranged reinforced fibers. The length of each of the reinforced fibers is in the range of 5 to 100 mm. The chopped fiber bundle has a transition segment in which the number of the reinforced fibers increases toward the central part of the chopped fiber bundle in the aligned direction of the reinforced fibers with both ends in the aligned of the reinforced fibers in the chopped fiber bundle being a starting point. The level of a change in total sectional area of the large number of reinforced fibers is not more than 0.05 mm2 per mm in the aligned direction of the reinforced fibers over the whole area in the longitudinal direction of the chopped fiber bundle.

Abstract: A composite prepreg base which includes a raw prepreg base comprising a fiber sheet comprising discontinuous reinforcing fibers arranged in one direction and having a fiber length of 1-300 mm and a matrix resin infiltrated into the fiber sheet; and an additional resin layer formed on at least one surface of the raw prepreg base. The composite prepreg base is produced by a process including (i) the step of preparing the raw prepreg base and (ii) the step of forming an additional resin layer on at least one surface of the raw prepreg base prepared. Also provided are: a layered base including two or more sheets of the composite prepreg base which have been superposed so that the additional resin layer is present on at least one surface; and a fiber-rein-forced plastic formed by heating and pressing the layered base.

Abstract: A fiber-reinforced plate-like plastic having a plate and a protrusion rising on the plate, wherein the plate and the protrusion each contain a laminated structure composed of plural reinforcing fiber sheets which each include many fibers of 10 to 100 mm in fiber length arranged in a fixed direction and at least two of the layers constituting the laminated structure are different in the direction of arrangement of reinforcing fibers and wherein at least part of the reinforcing fibers extend continuously from the plate to the protrusion and at least one of the layers constituting the laminated structure of the protrusion has a shape similar to the shape of the protrusion; and a process for the production of fiber-reinforced plastic which includes cutting a unidirectional prepreg sheet composed of many reinforcing fibers arranged in a fixed direction and a matrix resin into prepreg base material sheets with the above fiber length, laminating the prepreg base material sheets with the directions of arrangement of

Abstract: A prepreg base material includes reinforcing fibers arranged substantially in one direction and a matrix resin between the reinforcing fibers, wherein the prepreg base material has substantially throughout its entire surface incisions, each incision extending in a direction substantially crossing the reinforcing fibers, wherein substantially all of the reinforcing fibers are divided by the incisions, a length (L) of each of reinforcing fiber segments formed by the incisions is in the range of 10 to 100 mm, a thickness H of the prepreg base material is in the range of 30 to 300 ?m, and a fiber volume content by Vf of the reinforcing fibers is in the range of 45 to 65%.