POLYESTER FILAMENTARY YARN, POLYESTER TIRE CORD AND PRODUCTION THEREOF

摘要

A polyester filamentary yarn having a novel internal microstructure, a polyester tire cord produced from the yarn and a process for production thereof are provided. The polyester yarn of the present invention comprising at least 90 mol % polyethylene terephthalate and having a fineness of 3 to 5 denier per filament, wherein said yarn satisfies the following i) iii) characteristics, after it has been treated for 3 minutes at temperature of 240 ~C, tension of 0.1 g/d, said yarn satisfies the following iv) vii) variations of microstructural physical properties: i) a density of 1.38 1.39 g/cm3, ii) a birefringence index in amorphous portions of 0.06 0.09, iii) tan .delta. peak temperature of 140 ~C and below, iv) the increment of a percent crystallinity (.DELTA.Xc) of 10 20 wt.%, v) the decrement of an amorphous orientation coefficient (.DELTA.Fa) of at least 0.05, vi) the increment of a long period value (.DELTA.LP) of at least 10 .ANG., and vii) the decrement of tan .delta. peak temperature (.DELTA.tan.delta.peak) of at least 5 ~C. The filamentary yarn is dipped in a rubber solution to produce a tire cord which exhibits excellent dimensional stability and fatigue resistance when it has been incorporated in a rubber matrix of a tire.