The present invention relates to a method for producing a carbon nanotube fiber aggregate and provides a carbon nanotube fiber aggregate having an improved level of alignment through ultrasonic wave application and low speed recovery.

An object of the present invention is to provide a sizing agent composition that gives a carbon fiber from which a carbon fiber-reinforced composite material having excellent adhesion between a resin and the carbon fiber and having excellent mechanical properties can be formed. The sizing agent composition of the invention is a sizing agent composition comprising (A) a blocked isocyanate, and (B) a compound containing at least one polar group and at least one unsaturated group per molecule. In the invention, the mixing ratio (mass ratio) of the blocked isocyanate (A) and the compound (B) containing at least one polar group and at least one unsaturated group per molecule (A/B) is preferably 95/5 to 5/95. In the invention, the blocked isocyanate (A) is preferably a compound having an aliphatic skeleton.

The invention relates to fluoropolymer composites having a fluoropolymer matrix containing a functionalized fluoropolymer composition, and reinforced with fibers. The fibers can be chopped fibers, long fibers, or a mixture thereof, and the fluoropolymer matrix preferably is based on polyvinylidene fluoride. Any type of fibers, sized or unsized may be used with the functionalized fluoropolymer matrix composition to form the fluoropolymer composite.

A composite material includes a carbon fiber bundle including a plurality of continuous carbon fibers; and a structure, formed on each of the carbon fibers, including a plurality of carbon nanotubes and having a network structure in which the carbon nanotubes are in direct contact with each other and in which the carbon nanotubes directly adhere to surfaces of the carbon fibers. The carbon nanotubes have a bent shape including a bent portion, and a thickness of the structure is within a range of 50 nm to 200 nm.

The present application relates to a sizing agent composition, a carbon fiber material and a composite material. The sizing agent composition comprises specific compositions, thereby producing a sizing agent having emulsion droplets with specific diameter. The sizing agent has excellent emulsion stability, and it can efficiently improve hygroscopicity and dimensional stability of the carbon fiber material. Besides, the sizing agent can improve bonding properties between the carbon fiber material and resin matrix, therefore enhancing properties of the composite material.

A manufacturing method for an antibacterial fiber includes the following steps. A dipping step is performed to soak a conductive fiber in a solution, in which the solution includes an ionic compound, and the ionic compound includes a metal cation. An oxidation step is performed by using the conductive fiber as an anode, such that an antibacterial material produced by the solution is adhered to a surface of the conductive fiber, in which the antibacterial material includes a metal oxide.

[Problem] To provide a sizing-agent-coated carbon fiber bundle in which, even when the sizing-agent-coated carbon fiber bundle has superior handling properties, the sizing agent on the sizing-agent-coated carbon fiber bundle exhibits excellent solubility in water and the adhesion amount of remaining sizing agent is reduced. [Solution] A sizing-agent-coated carbon fiber bundle obtained by applying polyethylene glycol and/or a surfactant to a carbon fiber bundle as a sizing agent, wherein all of the following conditions (i)-(iii) are satisfied. (i) The adhesion amount of the sizing agent is 0.15-0.80 parts by mass (inclusive) per 100 mass parts of the sizing-agent-coated carbon fiber bundle 100. (ii) The dry F-F friction coefficient is 0.39 or less. (iii) The adhesion amount of the sizing agent after washing for 50 seconds under the conditions disclosed in the specification is 0.12 parts by mass or less per 100 parts by mass of the sizing-agent-coated carbon fiber bundle 100.

The present application relates to a sizing agent composition, a carbon fiber material and a composite material. The sizing agent composition includes a first composition solution and a second composition solution, and those solutions respectively has specific compound. The sizing agent comprising the composition has an excellent bonding property with a carbon fiber, and further the sizing agent can efficiently enhance heat resistance, wear resistance and processability of the carbon fiber material. The carbon fiber material sized with the sizing agent has a high adhesion property with specific resin material, therefore producing the composite material with high processability.

A sizing agent for matrix-resin-reinforcement fibers that simultaneously attains excellent cohesion and abrasion resistance of sized fibers, uniform size application on fiber surface and good bonding between sized fiber and a matrix resin; a synthetic fiber strand sized therewith; and a fiber-reinforced composite material reinforced by the sized fiber strand. The sizing agent contains a polyamide (A), a carbodiimide group-containing compound (B) and water (C), wherein the polyamide (A) has a melt viscosity ranging from 100 to 15,000 mPa.Math.s at 150° C. and the compound (B) has at least two carbodiimide groups per molecule. The polyamide (A) is preferably a water-soluble polyamide.

A carbon fiber is obtained by sequentially performing: a step (I) of dissolving a fullerene mixture including fullerenes C.sub.60 and C.sub.70 in an organic solvent to prepare a fullerene solution; a step (II) of immersing a material carbon fiber in the fullerene solution; and a step (III) of extracting the carbon fiber from the fullerene solution and drying the extracted carbon fiber.