| 摘要 |
PURPOSE: A high-efficiency radial tire using polyethylene naphthalate is provided to make high-strength polyethylene naphthalate by regulating properly the birefringence ratio and melting point rise of undrawn yarns and to use a cord made of the undrawn yarns with excellent dimensional stability and strength as a stiffener for rubber products or other industrial purposes. CONSTITUTION: In a high-efficiency radial tire(11) with a dip cord made of polyethylene naphthalate fibers and applied to a carcass unit, the polyethylene naphthalate 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%. The dip cord has total denier of 3000¯5500d, 250¯500TPM(Twist Per Minute), and reinforcing density of 15¯30EPI. The aspect ratio of the radial tire is below 0.6.
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