| 摘要 |
PURPOSE:To improve fatigue resistance by subjecting a polyamide fiber having prescribed characteristics to upper and lower twisting in a tire employing a cord made of polyamide fiber as a carcass ply. CONSTITUTION:In a tire reinforced by using a cord made of a polyamide fiber as a carcass ply layer 1, and providing a braker layer 4 on a crown part 3 of said layer, said polyamide fiber is >=2.3 in relative viscosity of the fiber in itself (using an aqueous 96% concentrated sulfuric acid solution measured at a polymer concentration of 10mg/ml and at temperature of 20 deg.C). In addition, said fiber has the following characteristics for use: double refractive index in its cross section DELTAnA-DELTAnB, double refractive index DELTAn>=50X10<-3>, cut-through strength (g/d)>=11.0, fiber length period by small angle X-ray diffraction (Angstrom ) >=100, specific gravity 1.140, degree of shrinkage under dry heat (%) <=15. A plyamide cord is obtained by subjecting the above described polyamide fiber to upper and lower twisting. |
