Abstract: This prepreg comprises reinforcing fibers and a matrix resin composition. The matrix resin composition comprises at least an epoxy resin (component (A)), a radical polymerizable unsaturated compound (component (B)), and a polymer formed by radical polymerization of the component (B) (component (E)).

Abstract: The present invention relates to a method for producing a prepreg which contains reinforcing fibers and a matrix resin composition with the weight per square meter of the reinforcing fibers being 250-2,000 g/m2. The production method comprises the following steps (1)-(3): (1) a matrix resin composition blending step for obtaining a matrix resin composition by mixing an epoxy resin, a radically polymerizable unsaturated compound, an epoxy resin curing agent and a polymerization initiator that generates radicals, in said step the content of the radically polymerizable unsaturated compound relative to 100% by mass of the total of the epoxy resin and the radically polymerizable unsaturated compound being 10-25% by mass; (2) a matrix resin composition impregnating step; and (3) a surface viscosity increasing step.

Abstract: This prepreg comprises reinforcing fibers and a matrix resin composition. The matrix resin composition comprises at least an epoxy resin (component (A)), a radical polymerizable unsaturated compound (component (B)), and a polymer formed by radical polymerization of the component (B) (component (E)).

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: The present invention relates to a method for producing a prepreg which contains reinforcing fibers and a matrix resin composition with the weight per square meter of the reinforcing fibers being 250-2,000 g/m2. The production method comprises the following steps (1)-(3): (1) a matrix resin composition blending step for obtaining a matrix resin composition by mixing an epoxy resin, a radically polymerizable unsaturated compound, an epoxy resin curing agent and a polymerization initiator that generates radicals, in said step the content of the radically polymerizable unsaturated compound relative to 100% by mass of the total of the epoxy resin and the radically polymerizable unsaturated compound being 10-25% by mass; (2) a matrix resin composition impregnating step; and (3) a surface viscosity increasing step.

Abstract: Provided are: a carbon fiber bundle which has a large value of single-fiber fineness and excellent productivity and which, despite this, contains few interlaced single fibers therein and has excellent spreadability; and precursor fibers which are suitable for use in producing the carbon fiber bundle. The precursor fibers are a carbon-fiber-precursor acrylic fiber bundle which comprises a polyacrylonitrile copolymer comprising 95-99 mol % acrylonitrile units and 1-5 mol % hydroxyalkyl (meth)acrylate units and which has a single-fiber fineness of 1.5-5.0 dtex. In the acrylic fiber bundle, the cross-section of each single fiber which is perpendicular to the fiber axis has a shape that has a roundness of 0.9 or less.

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: 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: A prepreg is provided capable of being a composite material having suitable high heat resistance, impact resistance, and mechanical properties under high temperature and high humidity conditions. As the matrix resin, a composition including a specific epoxy resin component (A), a specific bifunctional epoxy resin (B), a specific tetrafunctional epoxy resin (C), and a specific aromatic amine compound (D) at specific proportions are used. Particularly, as the epoxy resin component (A), one obtained by mixing and heating a bifunctional epoxy resin (a1), a trifunctional epoxy resin (a2), a phenol compound (a3), and a specific polyamide resin (a4) is used so as to be able to solve the above-described problems.

Abstract: A method for producing a fiber-reinforced composite material plate by heating and pressurizing a prepreg for a molding time of 15 minutes or less, at a molding temperature of at least 120° C. and a molding pressure of at least 10 kg/cm2. The prepreg is prepared from a reinforcing fiber and an epoxy resin composition. The epoxy resin composition features: an epoxy resin; an amine compound having at least one sulfur atom in the molecule thereof and/or a reaction product of the epoxy resin and the amine compound having at least one sulfur atom in the molecule thereof; a urea compound; and a dicyandiamide. The contents of the sulfur atom and the urea compound in the epoxy resin composition are 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: A prepreg is provided capable of being a composite material having suitable high heat resistance, impact resistance, and mechanical properties under high temperature and high humidity conditions. As the matrix resin, a composition including a specific epoxy resin component (A), a specific bifunctional epoxy resin (B), a specific tetrafunctional epoxy resin (C), and a specific aromatic amine compound (D) at specific proportions are used. Particularly, as the epoxy resin component (A), one obtained by mixing and heating a bifunctional epoxy resin (a1), a trifunctional epoxy resin (a2), a phenol compound (a3), and a specific polyamide resin (a4) is used so as to be able to solve the above-described problems.

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: 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: 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 hollow golf club head provides for a longer flight distance, a larger “sweet spot”, and reduced veering in the flight path than a conventional golf club head. The golf club head has a maximum weight of 200 g, a volume in the range from 300 to 900 cc and a moment of inertia of at least 4·10 −4 kg·m2. The head is made from a fiber reinforced epoxy resin which provides at least 30 kg/mm2. Suitable reinforcing fibers include carbon fiber, fiberglass, aramid fiber and polyester fiber. Suitable resin materials include epoxy resin, unsaturated polyester resin and vinyl ester resin. The reinforcing fibers in the resin are arranged such that adjacent layers of reinforcing material are oriented perpendicular to one another. The perpendicular orientation of the fibers provide shock resistance to the head. A high elasticity and high density component, such as tungsten, is dispersed in the resin to provide reduced vibrations and improved acoustics to the head when impacting a ball.