An object of the present invention is to provide an epoxy resin composition that can be preferably used for prepreg and fiber reinforced composite material applications and is excellent in elastic modulus, strength, and pot life. The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (4):

[A]: epoxy resin
[B]: aromatic diamine
[C]: a compound having a boiling point of 130° C. or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin (1): the ratio H/E between the amount by mole, E, of the epoxy group in the component [A] and the amount by mole, H, of active hydrogen in the component [B] is 0.50 or more and 1.30 or less. (2): at least a part of the component [C] satisfies 0.10 or more and 0.60 or less in a ratio m/M of a molecular weight m thereof to a theoretical molecular weight between crosslinking points, M, of a cured product of the epoxy resin composition. (3): the ratio C/E of the amount by mole, E, for epoxy groups of the component [A] to the amount by mole, C, of the component [C] satisfying the condition (2) is 0.01 or more and 0.20 or less; and (4): the viscosity at 70° C. for 2 hours is 5.0 times or less the initial viscosity at 70° C.

Provided is a method for producing a material that suppresses a decrease in the life of an insulation against surge voltage, that is, a material that provides a long dielectric breakdown lifetime. The method is a method for producing a fullerene-derivative-containing resin composition containing a fullerene derivative and a resin that has an affinity for a polar solvent, including: a step (I) of dispersing a fullerene derivative in a polar solvent; and a step (II) of mixing the polar solvent in which the fullerene derivative is dispersed with a resin that has an affinity for the polar solvent.

Provided is a prepreg containing a urethane (meth)acrylate (A), a polymerization initiator (B), and reinforcement fibers (C), characterized in that the polymerization initiator (B) is an alkyl peroxy ester compound having a 10-hour half-life temperature of 60° C. or higher and lower than 70° C. The prepreg has excellent storage stability and excellent moldability, even under the low-temperature molding condition of 110° C. or lower, and enables to obtain a molded article having excellent physical properties such as interlaminar shear strength. Therefore, the prepreg can be suitably used in automobile components, railway vehicle components, aerospace craft components, ship components, housing equipment components, sporting components, light vehicle components, building and civil engineering components, and casings of OA equipment and the like.

An epoxy resin composition comprises the following components [A] to [E]: [A] epoxy resin, [B] amine-type curing agent, [C] cure accelerator, and [D] red phosphorus. The epoxy resin composition contains, per 100 mass parts for the total amount of [A], 25-45 mass parts of [A1] a liquid bisphenolic epoxy resin and 20-40 mass parts of [A2] a phenol novolac-type epoxy resin, and has a content ratio of [E] to [D] ([E]/[D]) of at least 1. Provided are a light-weight fiber-reinforced composite material that exhibits an excellent flame retardancy and mechanical properties and does not produce halogen gas during combustion, and an epoxy resin composition that has a viscosity suitable for obtaining the fiber-reinforced composite material as well as prepregs.

A fiber-reinforced composite material includes a matrix resin, and reinforcing fibers, in which the matrix resin includes a polyaryl ketone resin and a resin having a nitrogen atom in a repeating structural unit. A surface of the fiber-reinforced composite material includes a portion in which a contact angle with water is 60° or less.

The present invention relates to a polymer composition comprising a (meth)acrylic polymer and a multistage polymer. In particular the present invention it relates to polymer composition comprising a (meth)acrylic polymer and a multistage polymer that can be used as a masterbatch. More particularly the present invention relates also to a process for preparing a polymer composition comprising a (meth)acrylic polymer and a multistage polymer by spray drying or coagulation.

A method for surface preparation of composite substrates prior to adhesive bonding. A curable surface treatment layer is applied onto a curable, resin-based composite substrate, followed by co-curing. After co-curing, the composite substrate is fully cured but the surface treatment layer remains partially cured. The surface treatment layer may be a resin film or a removal peel ply composed of resin-impregnated fabric. After surface preparation, the composite substrate is provided with a chemically-active, bondable surface that can be adhesively bonded to another composite substrate to form a covalently-bonded structure.

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/m.sup.2 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. The prepreg exhibits high impact strength when formed into a fiber-reinforced plastic suitable for an aircraft structural member, and the prepreg also has excellent drapeability when a prepreg laminate is made to conform to a three dimensional shape.

Provided are tubular carbon fiber reinforced composite material and having excellent cylindrical bending strength and a golf club shaft using the same. This tubular carbon fiber reinforced composite material is formed by laminating and curing a straight layer and a bias layer. The straight layer comprises carbon fibers S coated with a sizing agent S and arranged in parallel in a direction of −20° to +20° with respect to the axis of the tubular body, and contains a thermosetting resin S. The bias layer comprises carbon fibers B coated with a sizing agent B and arranged in parallel in a direction of +25° to +65° with respect to the axis of the tubular body, and contains a thermosetting resin B. The carbon fiber reinforced composite material constituting the bias layer has an interlaminar shear strength of not less than 110 MPa. A cured product of the thermosetting resin S has an elastic modulus of not less than 4.0 GPa.

The present invention relates to a phosphazene compound containing an ester group having a structure of formula (I). The present invention grafts ester groups to phosphazene compounds and makes terminal grafted hydroxyl and carboxyl groups reacted with polymer matrix, producing an improvement of flame retardancy and a reduction of dielectric constant at the same time when the phosphazene compound is introduced into polymer matrix. Since N and P atoms are directly bonded into the polymer matrix by a reaction rather than addition and combination means in the prior art, there is no reduced mechanical properties of the matrix due to the addition of flame retardants.