Abstract: An intermediate base material is provided that is excellent in the conformity to three-dimensional shapes and that, when formed into a fiber reinforced plastic, develops good surface quality and high mechanical properties. According to one aspect, an incised prepreg is provided that has, in at least a partial region in a prepreg that contains unidirectionally oriented reinforcing fibers and a resin, a plurality of incisions that divide reinforcing fibers, wherein, in the case where a population is made up of the numbers of incisions contained in ten small circular regions of 10 mm in diameter randomly selected in the aforementioned region, a mean value for the population is 10 or greater and a coefficient of variation therefor is within 20%.

Abstract: A prepreg is described having good handleability and a low resin flow, facilitating the work in the process of a molded body and improving the dimensional accuracy of the molded body, where the prepreg includes a fiber substrate; and a resin layer containing a thermosetting resin composition containing at least components [A] and [B] below, stacked on one surface of the fiber substrate, wherein the fiber substrate is impregnated with a part of the thermosetting resin composition of the resin layer, the thermosetting resin composition having a complex viscosity ?3*24 at 24° C. of 20,000 to 100,000 Pa·s and a complex viscosity ?3*70 at 70° C. of 100 to 5,000 Pa·s, and a volatile amount of the thermosetting resin composition is 1 mass % or less when a total mass of the prepreg is 100 mass %.

Abstract: A surface protect material is described that is high in UV resistance, able to protect the surface of the prepreg used as the parent material, able to prevent a fiber composite material from being deteriorated by UV, able to prevent defects during painting, able to serve for control of the resin flow, and is low in the volatilization percentage during curing, where the surface protect material is a coating agent for spraying or manual application comprising an epoxy resin composition containing at least the components [A] to [D]: [A] non-aromatic epoxy resin, [B] pigment having an number average particle size of 0.1 to 10 ?m, [C] non-aromatic thermoplastic resin, and [D] cationic curing agent or anionic curing agent.

Abstract: A towpreg that is easy to unwind from a bobbin, has good width accuracy after unwinding and can produce a composite material with excellent heat resistance, and a resin composition that gives such a towpreg. A towpreg is characterized by being impregnated with an epoxy resin that contains an epoxy resin which is solid at 23° C. in an amount of 30 parts or more in 100 parts by mass of total epoxy resin components, contains a polyfunctional amine type epoxy resin which is liquid at 23° C. in an amount of 20 parts or more in 100 parts by mass of total epoxy resin components, and further contains a clay mineral.

Abstract: The present invention relates to a method for producing a towpreg by impregnating a plurality of fiber bundles with a resin to form a single towpreg, characterized in that the method comprises providing a stock of fiber bundles for preparing a towpreg; measuring a basis weight for each of the fiber bundles of said stock before impregnation by a resin; defining groups of fiber bundles from said stock based of the fiber basis weight, thereby providing determined fiber bundles; predicting a fiber basis weight of a towpreg when the plurality of fiber bundles is combined to form the towpreg, thereby providing a predicted fiber basis weight of a towpreg; and producing the towpreg using a combination of fiber bundles from all groups of determined fiber bundles in which the predicted fiber basis weight of the towpreg is in a range determined from a target value of a basis weight of a towpreg.

Abstract: A substantially flat-plate-shaped laminated base material has at least a layer-shaped body ? and a layer-shaped body ? are layered or disposed side by side, the layer-shaped body ? having one or more cut prepregs A in which reinforcing fibers oriented in one direction are impregnated with a resin composition, the volume fraction of fiber is 45-65%, and at least a portion of the reinforcing fibers are segmented into a fiber length of 10-300 mm by a plurality of cuts, and the layer-shaped body ? having one or more base materials B in which reinforcing fibers having a fiber length in the range of 10-300 mm are impregnated with a resin composition.

Abstract: A random mat material including fiber bundles, said fiber bundles including fibers having an average fiber length of 5 to 100 mm, and having an average number N of fibers in the fiber bundle that satisfies: 1.5 × 10 5 D 2 < N < 4.5 × 10 5 D 2 wherein D is the average diameter of fibers in the fiber bundle, expressed in micrometers, and the standard deviation SDN of the number of fibers in a fiber bundle satisfies: 1,000<SDN<6,000 wherein at an end of the fiber bundle, the number of the fibers in a fiber bundle becomes less from center to edge of the fiber bundle in a fiber direction.

Abstract: A molded article of a fiber-reinforced resin contains at least a bundled aggregate [A] of discontinuous reinforcing fibers and a matrix resin [M], wherein the average layer thickness h in the molded article of the fiber-reinforced resin is 100 ?m or less and the CV value of the average layer thickness h is 40% or less; and a compression molding method therefor. It is possible to reliably and greatly reduce the occurrence of stress concentration in the molded article and to thereby achieve higher mechanical properties and further reduce variation in the mechanical properties.

Abstract: An intermediate base material is provided that is excellent in the conformity to three-dimensional shapes and that, when formed into a fiber reinforced plastic, develops good surface quality and high mechanical properties. According to one aspect, an incised prepreg is provided that has, in at least a partial region in a prepreg that contains unidirectionally oriented reinforcing fibers and a resin, a plurality of incisions that divide reinforcing fibers, wherein, in the case where a population is made up of the numbers of incisions contained in ten small circular regions of 10 mm in diameter randomly selected in the aforementioned region, a mean value for the population is 10 or greater and a coefficient of variation therefor is within 20%.

Abstract: An intermediate base material is provided that is excellent in the conformity to three-dimensional shapes and that, when formed into a fiber reinforced plastic, develops good surface quality and high mechanical properties. According to one aspect, an incised prepreg is provided that has, in at least a partial region in a prepreg that contains unidirectionally oriented reinforcing fibers and a resin, a plurality of incisions that divide reinforcing fibers, wherein, in the case where a population is made up of the numbers of incisions contained in ten small circular regions of 10 mm in diameter randomly selected in the aforementioned region, a mean value for the population is 10 or greater and a coefficient of variation therefor is within 20%.

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 prepreg includes a fiber layer containing unidirectionally arranged carbon fibers impregnated with a thermosetting resin and a resin layer existing on at least one side of the fiber layer and containing a thermosetting resin and a thermoplastic resin insoluble in the thermosetting resin. The prepreg contains carbon fibers having an areal weight of fibers of 120 to 300 g/m2 and has a weight fraction of resin of 25 to 50 mass %. An extreme value frequency of a surface geometry along a straight line perpendicular to the fibers of the prepreg is 30 points/mm or less when the prepreg has been exposed, for 24 hours, to a temperature at which a coefficient of interlayer friction is the lowest. Using sheets of the prepreg which are laid up, the coefficient of interlayer friction of the prepreg is measured at 10° C. intervals in a temperature range of 40 to 80° C. under the conditions: a pulling speed of 0.2 mm/min, a perpendicular stress of 0.1 bar, and a pulling displacement of 1 mm.

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 random mat material including fiber bundles, said fiber bundles including fibers having an average fiber length of 5 to 100 mm, and having an average number N of fibers in the fiber bundle that satisfies: 1.5 × 10 5 D 2 < N < 4.5 × 10 5 D 2 wherein D is the average diameter of fibers in the fiber bundle, expressed in micrometers, and the standard deviation SDN of the number of fibers in a fiber bundle satisfies: 1,000<SDN<6,000 wherein at an end of the fiber bundle, the number of the fibers in a fiber bundle becomes less from center to edge of the fiber bundle in a fiber direction.

Abstract: A prepreg, including: a fiber layer containing unidirectionally arranged discontinuous carbon fibers and a thermosetting resin; and a resin layer existing on at least one side of said fiber layer and containing a thermosetting resin and a thermoplastic resin; in which said prepreg contains carbon fibers having an areal weight of fibers of 120 to 300 g/m2, and has a mass fraction of resin of 25 to 50% with respect to the whole mass of said prepreg; and in which a temperature at which a coefficient of interlayer friction is 0.05 or less is in a temperature range of from 40 to 80° C., the interlayer friction being caused at the contact interface between layers of said prepreg when the middle one of three layers that are each made of said prepreg and laid up is pulled out, said coefficient of interlayer friction being measured at 10° C. intervals in a temperature range of from 40 to 80° C. under conditions including a pulling speed of 0.2 mm/min, a perpendicular stress of 0.08 MPa, and a pulling length of 1 mm.

Abstract: A molded article of a fiber-reinforced resin contains at least a bundled aggregate [A] of discontinuous reinforcing fibers and a matrix resin [M], wherein the average layer thickness h in the molded article of the fiber-reinforced resin is 100 ?m or less and the CV value of the average layer thickness h is 40% or less; and a compression molding method therefor. It is possible to reliably and greatly reduce the occurrence of stress concentration in the molded article and to thereby achieve higher mechanical properties and further reduce variation in the mechanical properties.

Abstract: A method of producing a fiber reinforced plastic includes a laminating step of laminating a plurality of groups of prepregs containing an incised prepreg to obtain a prepreg laminate, when the incised prepreg is formed by providing at least a partial region in a prepreg containing unidirectionally oriented reinforcing fibers and a resin with a plurality of incisions that divide the reinforcing fibers, a forming step of disposing the prepreg laminate on a top surface of a mold containing the top surface and a side surface or disposing the prepreg laminate on a bottom surface of a mold containing the bottom surface and a side surface, and bending and forming the prepreg laminate along the side surface to obtain a preform having an approximate shape of the mold, and a solidifying step of disposing and solidifying the preform in a mold different than the mold used in the forming step.

Abstract: A substantially flat-plate-shaped laminated base material has at least a layer-shaped body ? and a layer-shaped body ? are layered or disposed side by side, the layer-shaped body ? having one or more cut prepregs A in which reinforcing fibers oriented in one direction are impregnated with a resin composition, the volume fraction of fiber is 45-65%, and at least a portion of the reinforcing fibers are segmented into a fiber length of 10-300 mm by a plurality of cuts, and the layer-shaped body ? having one or more base materials B in which reinforcing fibers having a fiber length in the range of 10-300 mm are impregnated with a resin composition.

Abstract: A prepreg includes a fiber layer containing unidirectionally arranged carbon fibers impregnated with a thermosetting resin and a resin layer existing on at least one side of the fiber layer and containing a thermosetting resin and a thermoplastic resin insoluble in the thermosetting resin. The prepreg contains carbon fibers having an areal weight of fibers of 120 to 300 g/m2 and has a weight fraction of resin of 25 to 50 mass %. An extreme value frequency of a surface geometry along a straight line perpendicular to the fibers of the prepreg is 30 points/mm or less when the prepreg has been exposed, for 24 hours, to a temperature at which a coefficient of interlayer friction is the lowest. Using sheets of the prepreg which are laid up, the coefficient of interlayer friction of the prepreg is measured at 10° C. intervals in a temperature range of 40 to 80° C. under the conditions: a pulling speed of 0.2 mm/min, a perpendicular stress of 0.1 bar, and a pulling displacement of 1 mm.

Abstract: An intermediate base material is provided that is excellent in the conformity to three-dimensional shapes and that, when formed into a fiber reinforced plastic, develops good surface quality and high mechanical properties. According to one aspect, an incised prepreg is provided that has, in at least a partial region in a prepreg that contains unidirectionally oriented reinforcing fibers and a resin, a plurality of incisions that divide reinforcing fibers, wherein, in the case where a population is made up of the numbers of incisions contained in ten small circular regions of 10 mm in diameter randomly selected in the aforementioned region, a mean value for the population is 10 or greater and a coefficient of variation therefor is within 20%.