HIGH-SPEED LIGHT RADIAL TIRE APPLYING PEN FIBER WITH PROPER TOTAL DENIER AND TWIST NUMBERS AND MODULUS OF ELASTICITY TO A CARCASS CORD AND A CAPPLY OF THE TIRE

摘要

PURPOSE: A high-speed light radial tire is provided to obtain a satisfied result for durability, riding comfort, and operation stability of the tire by applying a PEN(Polyethylene Naphthalate) cord to a carcass layer and a belt reinforcing layer of the tire. CONSTITUTION: A high-speed light radial tire(11) is composed of a carcass layer(12), a belt layer layered on the outer periphery of the carcass layer, and an organic belt reinforcing layer formed circumferentially around the outer periphery of the belt layer. A dip cord used for the carcass layer and the belt reinforcing layer is made from PEN fiber with the following properties. The PEN fiber has intrinsic viscosity of 0.6¯1.0, strength over 8.5g/d, elongation over 6%, birefringence ratio over 0.35, density of 1.355¯1.375, melting point of 270¯285deg.C, and shrinkage of 1¯4%.