POLYESTER FILAMENTARY YARN, POLYESTER TIRE CORD AND PRODUCTION THEREOF

摘要

A polyester multi-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 has a novel three-phase microstructure consisting of crystalline, amorphous and mesomorphous portions which will be changed to, in the formation of a tire cord, a definite structure of crystalline and amorphous portions. The polyester resin comprising at least 90 mol% polyethylene therephthalate is melt-spun and solidified by quenching to produce a undrawn yarn with a birefringence of 0.03 to 0.08, which is then drawn at a total draw ratio of 1.4: 1 to 2.2: 1 and thermally treated and relaxed. The resulting 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.