Toray Industries, Inc.

Masanobu Kobayashi

Nobuyuki Arai

Makoto Endo

Jun Misumi

Hiroshi Taiko

Tomoko Ichikawa

Yoji Matsuhisa

Kazuharu Shimizu

Motoi Itoh

Akihiko Kitano

Masayoshi Yamagiwa

Kenichi Noguchi

Yasushi Iida

Mitsutoshi Ozaki

Youji Matsuhisa

Akira Okuda

Motoi Ito

A prepreg includes; sizing agent-coated carbon fibers coated with a sizing agent; and a thermosetting resin composition impregnated into the sizing agent-coated carbon fibers. The sizing agent includes an aliphatic epoxy compound (A) and an aromatic compound (B) at least containing an aromatic epoxy compound (B1). The thermosetting resin composition includes a thermosetting resin (D) and a latent hardener (E), and optionally includes an additive (F) other than the thermosetting resin (D) and the latent hardener (E). The (a)/(b) ratio is within a predetermined range where (a) is the height of a component at a binding energy assigned to CHx, C&#x2014;C, and C&#x2550;C and (b) is the height of a component at a binding energy assigned to C&#x2014;O in a Ccore spectrum of the surfaces of the sizing agent-coated carbon fibers analyzed by X-ray photoelectron spectroscopy.

Prepreg and carbon fiber-reinforced composite material

Sizing agent-coated carbon fibers includes: a sizing agent including an aliphatic epoxy compound (A) and at least containing an aromatic epoxy compound (B1) as an aromatic compound (B); and carbon fibers coated with the sizing agent, wherein the sizing agent-coated carbon fibers have an (a)/(b) ratio of 0.50 to 0.90 where (a) is a height (cps) of a component at a binding energy (284.6 eV) assigned to CHx, C&#x2014;C, and C&#x2550;C and (b) is a height (cps) of a component at a binding energy (286.1 eV) assigned to C&#x2014;O in a Ccore spectrum of a surface of the sizing agent applied onto the carbon fibers analyzed by X-ray photoelectron spectroscopy using AlK&#x3b1;as an X-ray source at a photoelectron takeoff angle of 15&#xb0;.

Sizing agent-coated carbon fibers, process for producing sizing agent-coated carbon fibers, prepreg, and carbon fiber reinforced composite material

A prepreg is formed by impregnating sizing agent-coated carbon fibers coated with a sizing agent with a thermosetting resin composition. The sizing agent contains an aliphatic epoxy compound (A) and an aromatic compound (B) at least containing an aromatic epoxy compound (B1). The sizing agent-coated carbon fibers has an (a)/(b) ratio of 0.50 to 0.90 where (a) is a height (cps) of a component at a binding energy (284.6 eV) assigned to CHx, C&#x2014;C, and C&#x2550;C and (b) is a height (cps) of a component at a binding energy (286.1 eV) assigned to C&#x2014;O in a Ccore spectrum of a surface of the sizing agent applied onto the carbon fibers analyzed by X-ray photoelectron spectroscopy using AlK&#x3b1;as an X-ray source at a photoelectron takeoff angle of 15&#xb0;.

Prepreg and carbon fiber reinforced composite material

A prepreg includes; agent-coated carbon fibers coated with a sizing agent; and a thermosetting resin composition impregnated into the sizing agent-coated carbon fibers. The sizing agent includes an aliphatic epoxy compound (A) and an aromatic epoxy compound (B1). The sizing agent-coated carbon fibers are in a shape of woven fabric or braid. The thermosetting resin composition includes a thermosetting resin (D), a thermoplastic resin (F), and a latent hardener (G). The sizing agent-coated carbon fibers have an (a)/(b) ratio in a certain range where (a) is the height of a component at a binding energy assigned to CHx, C&#x2014;C, and C&#x2550;C and (b) is the height of a component at a binding energy assigned to C&#x2014;O in a Ccore spectrum of the surfaces of the sizing agent-coated carbon fibers analyzed by X-ray photoelectron spectroscopy.

The pressure vessel of the present invention comprises an inner shell capable of serving as a gas barrier and a pressure resistant outer shell provided to cover the inner shell, said outer shell being made of an FRP comprising reinforcing fibers and a resin and is 35 GPa or more in tensile modulus and 1.5% or more in tensile breaking strain. The present invention can provide a pressure vessel not only light in weight,.but also excellent in retaining its internal pressure against repetitive impacts and also excellent in reliability. The process for producing a pressure vessel of the present invention comprises the step of forming a pressure resistant outer shell made of an FRP comprising reinforcing fibers and a resin and is 35 GPa or more in tensile modulus and 1.5% or more in tensile breaking strain, around an inner shell capable of serving as a gas barrier, by a filament winding method or a tape winding method. The present invention can produce a pressure vessel excellent in retaining its internal pressure, excellent in reliability, and light in weight at a low cost.

Pressure vessel and process for producing the same

Carbon-fibers and a method of producing them

The carbon fibers of the present invention have a polymer having polar groups and groups capable of reacting with a matrix resin deposited on the fiber surfaces. The carbon fibers can be produced by depositing a monomer having both polar groups and groups capable of reacting with the matrix resin or a mixture of a monomer having polar groups and a monomer having groups capable of reacting with the matrix resin onto the fiber surface and heating to polymerize the monomer(s) forming a polymer having polar groups and groups capable of reacting with a matrix resin. The resultant fibers have excellent adhesion properties to the matrix resin and are unlikely to cause fluffing and fiber breakage.

Carbon fibers and process for the production thereof

The pressure vessel of the present invention comprises an inner shell capable of serving as a gas barrier and a pressure resistant outer shell provided to cover the inner shell, said outer shell being made of an FRP comprising reinforcing fibers and a resin and is 35 GPa or more in tensile modulus and 1.5% or more in tensile breaking strain. The present invention can provide a pressure vessel not only light in weight, but also excellent in retaining its internal pressure against repetitive impacts and also excellent in reliability. The process for producing a pressure vessel of the present invention comprises the step of forming a pressure resistant outer shell made of an FRP comprising reinforcing fibers and a resin and is 35 GPa or more in tensile modulus and 1.5% or more in tensile breaking strain, around an inner shell capable of serving as a gas barrier, by a filament winding method or a tape winding method. The present invention can produce a pressure vessel excellent in retaining its internal pressure, excellent in reliability, and light in weight at a low cost.

Large-scale columnar structure made of a fiber reinforced plastic

Prepregs and carbon fiber-reinforced composite materials

Carbon fibers with a surface oxygen concentration (O/C ratio) of 0.20 or less as measured by X-ray photoelectron spectroscopy, a surface concentration of hydroxyl groups (C--OH/C ratio) of 0.5% or greater as measured by chemical modification X-ray photoelectron spectroscopy and a surface concentration of carboxylic groups (COOH/C ratio) of 2.0% or less as measured by chemical modification X-ray photoelectron spectroscopy, and an aliphatic compound applied as a sizing agent which has multiple epoxy groups or an aromatic compound which has multiple epoxy groups, the number of atoms between the epoxy groups and an aromatic ring being 6 or greater.

Carbon fibers and process for preparing same

A process for preparing carbon fibers including electrolyzing a carbon fiber in an alkaline aqueous solution, or electrolyzing a carbon fiber in an acidic aqueous solution followed by washing with an alkaline aqueous solution, and then applying a sizing agent of an aliphatic compound with multiple epoxy groups or an aromatic compound with multiple epoxy groups in which the number of atoms between the epoxy groups and an aromatic ring is 6 or greater. Alternatively, the carbon fibers are prepared by electrolyzing a carbon fiber in an aqueous solution of an ammonium salt and then applying a sizing agent of an aliphatic compound with multiple epoxy groups or an aromatic compound with multiple epoxy groups in which the number of atoms between the epoxy groups and an aromatic ring is 6 or greater.

Method for preparing carbon fibers

Carbon fibers with a surface oxygen concentration (O/C ratio) of 0.20 or less as measured by X-ray photoelectron spectroscopy, a surface concentration of hydroxyl groups (C-OH/C ratio) of 0.5% or greater as measured by chemical modification X-ray photoelectron spectroscopy and a surface concentration of carboxylic groups (COOH/C ratio) of 2.0% or less as measured by chemical modification X-ray photoelectron spectroscopy, and an aliphatic compound applied as a sizing agent which has multiple epoxy groups or an aromatic compound which has multiple epoxy groups, the number of atoms between the epoxy groups and an aromatic ring being 6 or greater.

Growing community of inventors

Ehime, Japan

Masanobu Kobayashi