Provided are: chopped carbon fiber bundles which have high fluidity without decreasing the dispersibility of carbon fibers and the physical properties of a molded product; and a method for producing chopped carbon fiber bundles with high productivity. Chopped carbon fiber bundles, each of which contain a carbon fiber bundle having a total fineness of from 25,000 dtex to 45,000 dtex (inclusive) and a sizing agent in an amount of from 1% by mass to 5% by mass (inclusive) relative to the total mass of the chopped carbon fiber bundle. The length (L) of each chopped carbon fiber bundle along the fiber direction of the carbon fiber bundle is from 1 mm to 50 mm (inclusive); the ratio of the longest diameter (Dmax) to the shortest diameter (Dmin) of a cross section perpendicular to the fiber direction of each chopped carbon fiber bundle, namely Dmax/Dmin is from 6.0 to 18.0 (inclusive); and the orientation parameter of the single fibers present in the surface of each chopped carbon fiber bundle is 4.0 or less.

A fireproof, translucent, flexible coated fabric composite material for use in fire curtains. The composite material meets or exceeds regulatory requirements in terms of fire endurance and allows transmissivity of necessary amounts of light. The process of the present disclosure combines a silica fabric with a special refractory index controlled resin. This unique combination of materials can transform an opaque high temperature fabric into a translucent, and even transparent, composite which as the ability to resist high temperature, flame and smoke penetration that fills a needed gap in technology between visibility and fire resistance in the field of fire and smoke curtains used in civil construction.

The present invention provides thermosetting resin pre-impregnated or infused fiber materials or prepregs comprising a thermosetting resin mixture and a fiber material component of a heat resistant fiber, such as carbon fiber, having an areal weight of from 500 to 3,000 g/m2 having a coating of from 0.5 to 4 phr of a latent, particulate curative or solid curative, preferably, dicyandiamide, wherein the prepregs are infused with a thermosetting resin mixture comprising (a) at least one liquid epoxy resin, and (b) a hardener and/or a catalyst, as well as methods of making the same. The prepregs of present invention enables the simple provision of lightweight composites having consistent resin cure throughout.

The present invention relates to a prepreg which is manufactured by impregnating thermosetting resin composition and at least one thermoplastic additive into unidirectional carbon fiber, and to a resin composition for high speed curing prepreg for car body parts through press method and a prepreg product containing the same by differentiating a resin constituent, a resin equivalent weight, viscosity, gel time and glass transition temperature differing from those described in the prior art.

Provided is an epoxy-amine adduct that offers high reactivity, contributes to better adhesion between a resin and a reinforcing fiber in a fiber-reinforced composite material, and can be easily blended with another component such as a resin. The epoxy-amine adduct has two or more amino groups per molecule and is obtained by a reaction of an epoxy compound (A) having two or more alicyclic epoxy groups per molecule with an amine compound (B) having two or more amino groups per molecule. The epoxy compound (A) is preferably a compound represented by Formula (a): ##STR00001##

The purpose of the present invention is to provide a carbon fiber bundle for resin reinforcement purposes, which is produced using a sizing agent that can exert satisfactory interface adhesiveness to both of a carbon fiber bundle and a thermoplastic resin in the production of a carbon-fiber-reinforced thermoplastic resin, and which has satisfactory emulsion stability. One embodiment of the present invention is a carbon fiber bundle for resin reinforcement purposes, which comprises a carbon fiber bundle and a polymer adhered onto the carbon fiber bundle, wherein the polymer is produced by binding an acid-modified polyolefin having a polyolefin structure and an acidic group in the molecular structure thereof to a hydrophilic polymer having a weight average molecular weight (Mw) of 450 or more, and wherein the ratio of the mass of the polyolefin structure to the mass of the acidic group in the acid-modified polyolefin is 100:0.1 to 100:10, the ratio of the mass of the acid-modified polyolefin to the mass of the hydrophilic polymer is 100:1 to 100:100, and the content of the polymer in the carbon fiber bundle for resin reinforcement purposes is 0.1 to 8.0 mass % inclusive.

To provide surface-modified fibers and reinforcing fibers that are capable of enhancing the adhesiveness to rubber, without the use of resorcinol and formaldehyde, and a molded article using the same. Surface-modified fibers include fibers, and a surface-modifying layer covering at least a part of a surface of the fibers, and have a solid surface zeta potential on a surface of the surface-modifying layer of −20.0 to 30.0 mV.

Disclosed is a method for producing a prepreg, the prepreg having: a reinforcing fiber layer including reinforcing fibers and a resin composition containing component (A), component (B), and component (C), the reinforcing fibers being impregnated with the resin composition in between the fibers; and a surface fiber layer provided on the surface of the reinforcing fiber layer and including a fabric including polyamide fibers and a resin composition containing component (A), component (B), and component (C), the polyamide fibers being impregnated with the resin composition in between the fibers. The method for producing a prepreg includes a disposition step of disposing the fabric on the surface of a reinforcing fiber base material and an impregnation step of supplying a resin composition to the reinforcing fiber base material and impregnating the reinforcing fibers with the resin composition in between the fibers.

Provided are: a prepreg with low dielectric constant, low dielectric loss tangent, and improved adhesiveness to glass cloth; and a laminate for a circuit board. The prepreg is formed of the glass cloth serving as a base material and a semi-cured product of a thermosetting resin composition impregnated into the glass cloth, where the glass cloth comprises a treated surface treated by at least one type of silane coupling agent selected from methacryl-based silane coupling agents, acryl-based silane coupling agents, and isocyanate-based silane coupling agents, and the thermosetting resin composition contains polyphenyleneether having a terminal hydroxyl group modified with an ethylenically unsaturated compound in a main chain of the polyphenyleneether. The laminate for the circuit board is obtained by laminating the prepreg and a conductor layer.

A glass fiber fabric is impregnated with a colored resin having an opacifying property, a colored resin layer formed from the colored resin is provided on a first face of the glass fiber fabric, a transparent resin layer becoming transparent after being cured is provided on a second face of the glass fiber fabric, and thus a prepreg is formed.