AIRED TIRE HAVING EXCELLENT UNIFORMITY

摘要

PURPOSE:To obtain an aired-tyre having excellent uniformity and durability, by employing a polyester cord having specific composition of intermediate ductility and low dry thermal shrinkage for the carcassply. CONSTITUTION:Fused high degree of polymerization polyester containing more than 85mol% of ethylene terephtalate component is spinned through a spinning nozzle. Then while applying tension, the cooled and solidified string is extended to produce a filament having extreme viscosity higher than 0.8 and double refraction of 190X10<-3>-205X10<-3>. The dimenesional astable factor shown by the sum of the intermediate ductility of yarn composed of a bundle of said filaments under load of 2.3g/d and the dry thermal shrinkage when heated for 30min. under the temperature of 150 deg.C is set in the range of 8.5-18.0. Then said yarns are heated to produce strands which are bundled and thermally processed to produce a polyester cord having the dimensional astable factor lower than 8.5 which is employed for the carcassply of tire.