Abstract: A method for molding fiber-reinforced plastic. A core is formed in a desired shape by accommodating, in a flexible bag, a grain group containing plurality of grains. The core is placed inside a prepreg containing resin and fibers, and the prepreg, in which the core is housed is placed in a molding die and compression molded. When doing so, the grain group contains first and second grains (a,b) that satisfy the equation (1). (1) 1.1?(Da/Db)?2.0 In the equation Da is the grain diameter of the grains (a), and Db is the grain diameter of the grain (b). When using a molding die to mold a molded article having a cavity, the above mentioned molding method enables an increase in the internal pressure of the core in order to change the peripheral surface area of the core, without using a pressurized gas and/or pressurized liquid.

Abstract: Provided is a method for manufacturing a fiber-reinforced plastic molded body by which, when a molded article having a hollow part is being molded using a molding mold, it is possible to deform the peripheral surface area of a core by increasing the pressure inside the core without using pressurized gas or pressurized fluid. A group of particles and the like including a particle group and a core block is accommodated in a flexible bag to form a core. The particle group is composed of multiple rigid particles. The core is arranged inside a prepreg containing a resin and fibers, and the prepreg including the core is arranged inside a molding mold and is molded by applying pressure.

Abstract: The present invention relates to a method for molding fiber-reinforced plastic that is characterized: in comprising a process (1) for accommodating flowable grains comprising multiple particles in a flexible bag to form a core, a process (2) for interposing the core between fabric configured from fibers and placing the fabric and core inside a molding die, and a process (3) for injecting a resin into the molding die into which the fabric and core have been placed and curing; and in that, when performing the curing in process (3), a portion of one of the outer surfaces of the core is pressed and deformed by a pressing means to increase the internal pressure inside the core. The present invention provides a method for manufacturing fiber-reinforced plastics of excellent external appearance in which there are no defects such as wrinkles in the outer surface during forming using a core.

Abstract: A golf club head enables the initial velocity of a ball to be increased and enables the carry to be lengthened. In some example structures, the golf club includes a face plate formed from metal and club head body (e.g., a crown and sole) formed from fiber reinforced plastic. A weighted body is provided inside the rearmost portion of the golf club head and a low rigidity portion whose width becomes gradually narrower as it approaches the rearmost portion is provided in the crown extending from the vicinity of the face plate to the rearmost portion.

Abstract: The present invention relates to a method for molding fiber-reinforced plastic that is characterized: in comprising a process (1) for accommodating flowable grains comprising multiple particles in a flexible bag to form a core, a process (2) for interposing the core between fabric configured from fibers and placing the fabric and core inside a molding die, and a process (3) for injecting a resin into the molding die into which the fabric and core have been placed and curing; and in that, when performing the curing in process (3), a portion of one of the outer surfaces of the core is pressed and deformed by a pressing means to increase the internal pressure inside the core. The present invention provides a method for manufacturing fiber-reinforced plastics of excellent external appearance in which there are no defects such as wrinkles in the outer surface during forming using a core.

Abstract: A method for molding fiber-reinforced plastic. A core is formed in a desired shape by accommodating, in a flexible bag, a grain group containing plurality of grains. The core is placed inside a prepreg containing resin and fibers, and the prepreg, in which the core is housed is placed in a molding die and compression molded. When doing so, the grain group contains first and second grains (a,b) that satisfy the equation (1). (1) 1.1?(Da/Db)?2.0 In the equation Da is the grain diameter of the grains (a), and Db is the grain diameter of the grain (b). When using a molding die to mold a molded article having a cavity, the above mentioned molding method enables an increase in the internal pressure of the core in order to change the peripheral surface area of the core, without using a pressurized gas and/or pressurized liquid.

Abstract: A fiber reinforced composite material structure comprises a thin sheet that includes a first surface and a plurality of convex portions which protrude and are regularly arranged on the first surface and each of which includes a top face; and a surface material that includes a second surface and is bonded to the top faces on the second surface.

Abstract: The present invention applies to a molding method for a fiber-reinforced plastic structure having an internal cavity. Firstly, grain groups, which mainly consist of a plurality of high-rigidity grains, are accommodated in bags, and a plurality of cores are formed. A reinforcing fiber substrate, is placed between the plurality of adjacent cores so as to be interposed therebetween. For example, a plurality of molding base materials are prepared by surrounding each core with a prepreg, and the plurality of molding base materials are combined and placed inside a molding die, and the molding base materials are compression molded. When compression molding, a part of the outer surface of the cores is locally pressurized, and the internal pressure of the cores is increased, changing the shape thereof, thus eliminating voids that are present between the cores and the prepreg and/or the prepreg and the molding surface of the die.

Abstract: A method is presented for stably, highly, and efficiently producing a three-dimensional molded article of a fiber-reinforced composite material having a three-dimensional shape, uniform quality, and free from wrinkles by press molding a plurality of prepregs cut out in a predetermined shape and also to a molded article.

Abstract: A golf club head enables the initial velocity of a ball to be increased and enables the carry to be lengthened. In some example structures, the golf club includes a face plate formed from metal and club head body (e.g., a crown and sole) formed from fiber reinforced plastic. A weighted body is provided inside the rearmost portion of the golf club head and a low rigidity portion whose width becomes gradually narrower as it approaches the rearmost portion is provided in the crown extending from the vicinity of the face plate to the rearmost portion.

Abstract: The invention relates to a prepreg containing a reinforcing fiber, a sheet-like reinforcing fiber substrate including the reinforcing fiber, and a matrix resin, wherein the matrix resin is impregnated into the sheet-like reinforcing fiber substrate and also covers one surface of the sheet-like reinforcing fiber substrate, such that the matrix resin impregnation ratio is within a range of 35% to 95%. The invention also relates to a prepreg containing a reinforcing fiber substrate in the form of a sheet and formed from a reinforcing fiber woven fabric, and a matrix resin, wherein at least one surface of the reinforcing fiber substrate displays a sea-and-island-type pattern with resin-impregnated portions (island portions) and fiber portions (sea portions), such that a surface coverage of the matrix resin is within a range of 3% to 80%.

Abstract: This invention relates to a prepreg containing a reinforcing fiber, a reinforcing fiber substrate in the form of a sheet and containing the reinforcing fiber, and a matrix resin, such that the matrix resin is impregnated into the reinforcing fiber substrate and also covers one surface of the reinforcing fiber substrate, and an impregnation ratio of the matrix resin is within a range of 35% to 95%.

Abstract: A golf club head enables the initial velocity of a ball to be increased and enables the carry to be lengthened. In some example structures, the golf club includes a face plate formed from metal and club head body (e.g., a crown and sole) formed from fiber reinforced plastic. A weighted body is provided inside the rearmost portion of the golf club head and a low rigidity portion whose width becomes gradually narrower as it approaches the rearmost portion is provided in the crown extending from the vicinity of the face plate to the rearmost portion.

Abstract: An epoxy resin composition suitably used for a prepreg which can complete curing in a short time even at a low temperature and secure a sufficient usable period under preservation at room temperature, in comparison with conventional epoxy resin compositions. An epoxy resin composition comprising at least one of an epoxy resin, an amine compound having at least one sulfur atom in the molecule thereof, and a reaction product of an epoxy resin and an amine compound having at least one sulfur atom in the molecule thereof, and an amine compound having at least one sulfur atom in the molecule thereof, and a urea compound and a dicyandiamide, wherein each of the contents of the sulfur atom and the urea compound in the epoxy resin composition is respectively 0.2 to 7% by mass and 1 to 15% by mass.

Abstract: An epoxy resin composition suitably used for a prepreg which can complete curing in a short time even at a low temperature and secure a sufficient usable period under preservation at room temperature, in comparison with conventional epoxy resin compositions. An epoxy resin composition comprising at least one of an epoxy resin, an amine compound having at least one sulfur atom in the molecule thereof, and a reaction product of an epoxy resin and an amine compound having at least one sulfur atom in the molecule thereof, and an amine compound having at least one sulfur atom in the molecule thereof, and a urea compound and a dicyandiamide, wherein each of the contents of the sulfur atom and the urea compound in the epoxy resin composition is respectively 0.2 to 7% by mass and 1 to 15% by mass.

Abstract: The invention relates to a prepreg containing a reinforcing fiber, a sheet-like reinforcing fiber substrate including the reinforcing fiber, and a matrix resin, wherein the matrix resin is impregnated into the sheet-like reinforcing fiber substrate and also covers one surface of the sheet-like reinforcing fiber substrate, such that the matrix resin impregnation ratio is within a range of 35% to 95%. The invention also relates to a prepreg containing a reinforcing fiber substrate in the form of a sheet and formed from a reinforcing fiber woven fabric, and a matrix resin, wherein at least one surface of the reinforcing fiber substrate displays a sea-and-island-type pattern with resin-impregnated portions (island portions) and fiber portions (sea portions), such that a surface coverage of the matrix resin is within a range of 3% to 80%.

Abstract: A golf club head enables the initial velocity of a ball to be increased and enables the carry to be lengthened. In some example structures, the golf club includes a face plate formed from metal and club head body (e.g., a crown and sole) formed from fiber reinforced plastic. A weighted body is provided inside the rearmost portion of the golf club head and a low rigidity portion whose width becomes gradually narrower as it approaches the rearmost portion is provided in the crown extending from the vicinity of the face plate to the rearmost portion.

Abstract: A fiber reinforced plastic pipe is provided to prevent it from being damaged and make full use of its practical performance when the fiber reinforced plastic pipe, reduced in thickness and increased in diameter by pultrusion process, is reduced in the circumferential direction and inserted into a metal pipe. The fiber reinforced plastic pipe, reduced in thickness and increased in diameter by pultrusion process, includes a fiber bundle spun and aligned in the longitudinal direction, and circumferential reinforced fiber sheet provided at least on one of the outer and inner surface layers. The circumferential reinforced fiber sheet is inserted into the metal pipe to form a power transmission shaft such as an intermediate shaft for use with a propeller shaft or a drive shaft.

Abstract: A golf club head enables the initial velocity of a ball to be increased and enables the carry to be lengthened. In some example structures, the golf club includes a face plate formed from metal and club head body (e.g., a crown and sole) formed from fiber reinforced plastic. A weighted body is provided inside the rearmost portion of the golf club head and a low rigidity portion whose width becomes gradually narrower as it approaches the rearmost portion is provided in the crown extending from the vicinity of the face plate to the rearmost portion.

Abstract: An FRP is produced using a prepreg comprising reinforcing fiber, a sheet-like reinforcing fiber substrate containing reinforcing fiber, and a matrix resin, wherein the matrix resin is impregnated into the sheet-like reinforcing fiber substrate and also covers one surface of the sheet-like reinforcing fiber substrate, and the matrix resin impregnation ratio is within a range of 35% to 95%; a prepreg comprising reinforcing fiber, a sheet-like reinforcing fiber substrate containing reinforcing fiber, and a matrix resin, wherein the matrix resin exists on both surfaces of the sheet-like reinforcing fiber substrate, and the portion inside the sheet-like reinforcing fiber substrate into which the matrix resin has not been impregnated is continuous; or a prepreg comprising reinforcing fiber, a sheet-like reinforcing fiber substrate containing reinforcing fiber, and a matrix resin, wherein at least one surface exhibits a sea-and-island-type pattern comprising resin-impregnated portions (island portions) where the mat