Patent ID: 6764623
Filing Date: 2004-07-20
Classification: B60C,D02G,Y10T

Abstract:
A process for producing polyester filamentary yarn for tire cords from a polyester resin, comprising the steps of:melting at a temperature of 290Â° C. or below a polyester resin comprising at least 90 mol % of polyethylene terephthalate with an intrinsic viscosity of 0.7-1.2; filtering the molten resin for a filtering retention time of 10 min or below; spinning the filtered, molten resin by extrusion through a nozzle which has 250-500 holes, each ranging, in diameter, from 0.5 to 1.2 mm with a length/diameter ratio from 2 to 5; primarily quenching the extruded yarn at a temperature of 100-195Â° C. in a zone of 50 mm or more distance directly below the nozzle; secondarily quenching the yarn with quench air at its glass transition temperature (Tg) or below; taking off the yarn at a spinning stress of 0.3 g/d or greater; drawing the taken-off yarn at a total draw ratio of 1.3 or greater; and thermally treating the yarn at a temperature of 150-230Â° C.