A carbon nanotube yarn is coated with polyacrylonitrile to form a coated carbon nanotube yarn. The polyacrylonitrile is converted to crystalline carbon to form a layered carbon fiber with a sheath of the crystalline carbon and a core of the carbon nanotube yarn.

A laminated body formed by laminating a fiber substrate composed of a plurality of fibers and a polymer layer formed from a polymer latex. The polymer layer covers the fiber substrate in a state in which a portion of the polymer layer has permeated among the fibers. A ratio (t.sub.1/d) of a thickness t.sub.1 of the portion of the polymer layer that has permeated among the fibers (from a top surface of the fiber substrate) to a substrate layer average thickness d is 0.1 to 0.95. A thickness t.sub.2 of the portion of the polymer layer covering the top surface of the fiber substrate (from the top surface of the fiber substrate) is 80 m or more.

A carbon nanotube yarn is coated with polyacrylonitrile to form a coated carbon nanotube yarn. The polyacrylonitrile is converted to crystalline carbon to form a layered carbon fiber with a sheath of the crystalline carbon and a core of the carbon nanotube yarn.

A carbon nanotube yarn is coated with polyacrylonitrile to form a coated carbon nanotube yarn. The polyacrylonitrile is converted to crystalline carbon to form a layered carbon fiber with a sheath of the crystalline carbon and a core of the carbon nanotube yarn.

A damage resistant shoelace may include a lace and a treatment composition applied to at least a portion of the lace. The treatment composition may include a superglue adhesive, an adhesive, and a sealant, such as a liquid rubber sealant coating in aerosol form.

A bundle of carbon fibers has a value A obtained from a nonlinear approximation formula of a stress -strain curve in a tensile strength test of resin-impregnated strands and an orientation parameter (%) of crystallites in a wide-angle x-ray diffraction measurement which satisfy a predetermined relational expression, and has tensile strength with a predetermined value or more, and tensile modulus within a predetermined range and a product Ed/W of a ratio d/W of a single-fiber diameter d to a loop width W just before loop fracture evaluated by a single-fiber loop test and a tensile modulus E of the strands has a predetermined value or more, or apparent single-fiber stress has a predetermined value or more when the number of fiber breaks by a single-fiber fragmentation method for a single-fiber composite is 0.30 breaks/mm and when the number of the fiber breaks by the single-fiber fragmentation method for the single-fiber composite is 0.30 breaks/mm, the number of fiber breaks by a double-fiber fragmentation method for the single-fiber composite is within a predetermined range.

A bundle of carbon fibers has a value A obtained from a nonlinear approximation formula of a stress -strain curve in a tensile strength test of resin-impregnated strands and an orientation parameter (%) of crystallites in a wide-angle x-ray diffraction measurement which satisfy a predetermined relational expression, and has tensile strength with a predetermined value or more, and tensile modulus within a predetermined range and a product Ed/W of a ratio d/W of a single-fiber diameter d to a loop width W just before loop fracture evaluated by a single-fiber loop test and a tensile modulus E of the strands has a predetermined value or more, or apparent single-fiber stress has a predetermined value or more when the number of fiber breaks by a single-fiber fragmentation method for a single-fiber composite is 0.30 breaks/mm and when the number of the fiber breaks by the single-fiber fragmentation method for the single-fiber composite is 0.30 breaks/mm, the number of fiber breaks by a double-fiber fragmentation method for the single-fiber composite is within a predetermined range.

A rubber formed article includes a laminate in which a rubber layer of nitrile rubber is laminated on a fiber base material. The nitrile rubber contains a copolymer having 52 to 78% by weight of conjugated diene monomer units, 20 to 40% by weight of ,-ethylenically unsaturated nitrile monomer units, and 2 to 10% by weight of ethylenically unsaturated monocarboxylic acid monomer units. Stress at 50% elongation of the laminate is 20 N or smaller. A ratio of an area where rubber is visible when the laminate is viewed from the back side to an area of the laminate is 15% or less. The thickness of the rubber layer is 0.30 mm or less.

Provided are a reinforcing cord using a reinforcing fiber treating agent for improving the performance, particularly oil resistance, of rubber products, and a highly oil-resistant rubber product. By using a reinforcing fiber treating agent that has an ,-ethylenically unsaturated nitrile monomer unit content of 30-55 wt %, an acid group-containing ,-ethylenically unsaturated monomer unit content of 3-20 wt %, an iodine value of 120 or less and a tetrahydrofuran insoluble fraction of 30 wt % or more, the oil resistance of the reinforcing cord and thus the oil resistance of rubber products using the reinforcing cord are improved.

Provided are a reinforcing cord using a reinforcing fiber treating agent for improving the performance, particularly oil resistance, of rubber products, and a highly oil-resistant rubber product. By using a reinforcing fiber treating agent that has an ,-ethylenically unsaturated nitrile monomer unit content of 30-55 wt %, an acid group-containing ,-ethylenically unsaturated monomer unit content of 3-20 wt %, an iodine value of 120 or less and a tetrahydrofuran insoluble fraction of 30 wt % or more, the oil resistance of the reinforcing cord and thus the oil resistance of rubber products using the reinforcing cord are improved.