HIGH-PERFORMANCE RADIAL TIRE FOR IMPROVING ENDURANCE, RIDING COMFORT, AND OPERATION STABILITY BY APPLYING HIGH-STRENGTH PEN(POLYETHYLENE NAPHTHALATE) CORDS TO A CARCASS LAYER

摘要

PURPOSE: A high-performance radial tire is provided to produce high-strength polyethylene naphthalate fibers by improving elongation by regulating a force-strain curve and fine structure of non-elongated yarns and to use cords made from the yarns as a stiffener for tires and belts due to excellent dimensional stability and strength of the cord. CONSTITUTION: A high-performance radial tire(11) with aspect ratio below 0.65 is composed of a pair of bead cords parallel to each other; at least one radial carcass ply wound around a bead core(16); a belt layer layered on the outer periphery of the carcass; and a circumferential belt reinforcing layer formed at the outer periphery of the belt layer. The carcass ply has a dip cord made from polyethylene naphthalate fibers. The dip cord elongates below 2% for initial stress of 1.0d/g and has initial modulus of 50¯250g/d and a force-strain curve that the cord elongates maximally to 15% for load larger than the initial stress and below 6.0g/d. The dip cord has material properties satisfying strength over 6.5g/d, elongation over 6%, adhesive force with rubber over 10kg, fatigue resistance over 80%, and 2000¯8000 denier.