Abstract: The present invention provides: a carbon fiber sizing agent that can obtain a carbon fiber bundle having a superior effect of improving mechanical properties when composited using a resin; an aqueous dispersion thereof; a carbon fiber bundle; a sheet-shaped article having a carbon fiber bundle; and a composite material. The carbon fiber sizing agent contains: a compound (A) that is an ester of an unsaturated monobasic acid and an epoxy compound having a plurality of epoxy groups in the molecule, and that has at least one epoxy group in the molecule; a urethane acrylate oligomer (B) that is bifunctional and that has a tensile elongation rate of the cured product of at least 40%; and a polyurethane resin (C) having a tensile elongation rate of a dried coating film of 350-900% inclusive. The amounts of A-C contained satisfy the conditions described in the description. The aqueous dispersion disperses the sizing agent. The carbon fiber bundle contains 0.6-3.0 mass % inclusive of the sizing agent.

Abstract: The present invention provides: a carbon fiber sizing agent that can obtain a carbon fiber bundle having a superior effect of improving mechanical properties when composited using a resin; an aqueous dispersion thereof; a carbon fiber bundle; a sheet-shaped article having a carbon fiber bundle; and a composite material. The carbon fiber sizing agent contains: a compound (A) that is an ester of an unsaturated monobasic acid and an epoxy compound having a plurality of epoxy groups in the molecule, and that has at least one epoxy group in the molecule; a urethane acrylate oligomer (B) that is bifunctional and that has a tensile elongation rate of the cured product of at least 40%; and a polyurethane resin (C) having a tensile elongation rate of a dried coating film of 350-900% inclusive. The amounts of A-C contained satisfy the conditions described in the description. The aqueous dispersion disperses the sizing agent. The carbon fiber bundle contains 0.6-3.0 mass % inclusive of the sizing agent.

Abstract: Provided are: a carbon fiber bundle which has a large value of single-fiber fineness and excellent productivity and which, despite this, contains few interlaced single fibers therein and has excellent spreadability; and precursor fibers which are suitable for use in producing the carbon fiber bundle. The precursor fibers are a carbon-fiber-precursor acrylic fiber bundle which comprises a polyacrylonitrile copolymer comprising 95-99 mol % acrylonitrile units and 1-5 mol % hydroxyalkyl (meth)acrylate units and which has a single-fiber fineness of 1.5-5.0 dtex. In the acrylic fiber bundle, the cross-section of each single fiber which is perpendicular to the fiber axis has a shape that has a roundness of 0.9 or less.

Abstract: A detectable card is constituted by a sheet substrate made of a synthetic resin, a first capacitor including a pair of electrodes bonded to opposite surfaces of the substrate at the central portion, a second capacitor including a pair of electrodes bonded to the opposite surfaces of the substrate at the peripheries thereof, a spiral connector interconnecting a central electrode and peripheral electrode disposed, the spiral connector forming an inductance of an LC tuning circuit. The assembly is sealed in a cover made of inner and outer synthetic resin films.

Abstract: The magnetic card comprises upper and lower resinous pack films, a sheet printed with necessary items and sealed in the upper and lower resinous pack films. A magnetic band recorded with information is interposed between the sheet and the upper pack film. A magnetic card sheet utilized to form the magnetic card is prepared by simultaneously passing first and second synthetic resin films through a T die while the films are still soft. The second synthetic resin film is incorporated with a powder of iron oxide and one half of the T die is provided with a plurality of spaced parallel grooves so that the second synthetic resin film is embedded in the first synthetic resin film at the grooves. Then a third synthetic resin film having lower melting point than the first and second resin films is bonded to the first synthetic resin film to cover the second synthetic resin film in the grooves.