Provided are: a rubber-reinforcing fiber, in which adhesion between a rubber and a fiber is enhanced and which is thereby capable of further improving the durability than before when used as a reinforcing material; a rubber-fiber composite; and a pneumatic tire using the same. The rubber-reinforcing fiber includes a core-sheath type composite fiber whose core portion is composed of a high-melting-point resin (A) having a melting point of 150 C. or higher and sheath portion is composed of a resin material (B) having a melting point lower than that of the high-melting point resin (A). The resin material (B) includes an olefin-based copolymer composition (X) which contains two or more olefin-based polymers selected from a propylene--olefin copolymer (C1), a propylene-nonconjugated diene copolymer (C2), an ionomer (C3) whose degree of neutralization with a metal salt of an olefin-based copolymer containing a monomer of an unsaturated carboxylic acid or anhydride thereof is 20% or higher, and an olefin-based homopolymer or olefin-based copolymer (D) (excluding (C1) and (C2)).

A cord (1) for use in an elastomer product, preferably in a pneumatic tire, comprising a reinforcement system (2) which is made of an electrically nonconductive material and which is sheathed by an electrically conductive layer (5).

Located on the electrically conductive layer (5), covering same, there is a further, electrically insulating layer (6).

The invention relates to a duplex cord for use as strength member in a belt bandage of a pneumatic vehicle tire, consisting of exactly two yarns that are twisted together at the ends, wherein the first yarn has a Z value of 600 mN/tex or more, and wherein the second yarn has a Z value of 75 mN/tex or less and a Y value of 150 mN/tex or less, where Z is the force normalized to the linear yarn density at which an elongation of 1% is obtained in the force-elongation diagram, where Y is the force normalized to the linear yarn density at which an elongation of 4% is obtained in the force-elongation diagram, and where the quotient X of the linear density of the first yarn divided by the linear density of the second yarn is in the range from 1.0 to 1.3.

The present disclosure relates to a method for manufacturing a hybrid tire cord that utilizes a difference in fineness using a general-purpose industrial filament such as nylon and polyester having high fineness of 200 denier or more relative to a fineness of an aramid filament.

The tire has a radial carcass reinforcement which includes at least one layer of metal reinforcing elements and a crown reinforcement, which is capped radially with a tread. The metal reinforcing elements of at least one layer of the carcass reinforcement are cords with several steel threads that have a weight content of carbon C such that 0.01%C<0.4%. The cords exhibit, in the permeability test, a flow rate of less than or equal to 20 cm.sup.3/min. The thickness of the rubber compound between the inner surface of the tire cavity and the point of a metal reinforcing element of the carcass reinforcement that is closest to the inner surface of the cavity is less than 3.2 mm, and the steel threads have a maximum tensile strength R, expressed in MPa, such that R175+930.0-600.ln(d) and R1500 MPa.

The tire has a radial carcass reinforcement which includes at least one layer of metal reinforcing elements. The tire also has a crown reinforcement, itself capped radially with a tread. The tread is joined to two beads via two sidewalls. The metal reinforcing elements of at least one layer of the carcass reinforcement are cords include several steel threads having a weight content of carbon C such that 0.01%C<0.4%. The cords exhibit, in the permeability test, a flow rate which is strictly greater than 20 cm.sup.3/min, and the thickness of the rubber compound between the inner surface of the tire cavity and the point of a metal reinforcing element of the carcass reinforcement that is closest to the inner surface of the cavity is less than 3.2 mm.

Provided is a pneumatic tire with an annular-shaped tread portion extending in a tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed inward of these sidewall portions in a tire radial direction. This pneumatic tire is also provided with a reinforcing member which includes a plurality of reinforcing cords oriented in at least three directions, and has a mesh-like structure with at least three of the reinforcing cords oriented in different directions joined together at at least a portion of intersecting locations of the reinforcing cords.

An electrostatic energy generator may include one or more first tire cord fabrics each including a conductive material which is a wire-shaped electrode and a non-conductive material, the non-conductive material configured to surround an outer peripheral surface of the conductive material, and one or more second tire cord fabrics each including a conductive material which is a wire-shaped electrode, and a material configured to surround an outer peripheral surface of the conductive material that is different from the non-conductive material of the first tire cord fabric, wherein the first tire cord fabric and the second tire cord fabric are arranged in a longitudinal direction so as to be in contact with each other and form a bundle, such that frictional electricity is generated due to a friction between the first tire cord fabric and the second tire cord fabric.

A steel cord is obtained by bundling five steel core wires, which are arrayed in parallel with one another in a plane, into a unitary body by means of an adhesive having a thickness Ad of less than 15 m. Each of the core wires-constituting the steel cord has a diameter d of less than 0.45 mm, and spacing Gd between the core wires is less than 20 m. The core wires used have a free coil diameter D that is greater than wire diameter d thereof by 750 times or more.

In a pneumatic tire including one carcass layer and a tread portion comprising a cap tread layer and an under tread layer, the under tread layer comprises a rubber composition having hardness at 20 C. of 60 to 65, tensile stress at 100% elongation at 100 C. of 2.0 MPa to 4.0 MPa, and a product of tensile strength at 100 C. and an elongation at break at 100 C. of 2000 or more, the carcass layer comprises an organic fiber cord having an elongation ratio under a load of 1.5 cN/dtex on a belt layer inner circumferential side of 5.5% to 8.5% and an elongation at break of 20% to 30%, and a product A=DEc of a fineness based on corrected mass D per carcass cord and an insertion count Ec is from 1.810.sup.5 dtex/50 mm to 3.010.sup.5 dtex/50 mm.