Abstract: A sizing agent for carbon fibers includes 2 to 30 parts by weight of a resin main agent (A) having at least one epoxy compound, 2 to 30 parts by weight of a resin main agent (B) having at least one acrylate compound, 0.5 to 15 parts by weight of a surfactant (C), 0.01 to 0.5 parts by weight of a hindered phenol agent (D), and a balance of a solvent, in which a particle diameter of the sizing agent is in a range from 0.01 to 0.5 ?m.

Abstract: Disclosed is a method for processing a carbon fiber bundle, which can adjust bundling property, winding property and wear resistance of sizing fibers. The method includes following steps: (i) coating a sizing agent on at least one carbon fiber bundle, in which the sizing agent includes a thermoplastic resin; (ii) drying the carbon fiber bundle by hot air; and (iii) heating the carbon fiber bundle by an infrared light, in which a heating temperature of the heating is equal to or higher than a melting point of the thermoplastic resin.

Abstract: 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.