| 摘要 |
PURPOSE:To obtain the titled fiber having high strength, low shrinkage and excellent fatigue resistance in high yarn-productivity, by producing an undrawn polyester yarn having an intrinsic viscosity and a birefringence larger than respective specific levels by subjecting a melt-spun polyester fiber to a specific treatment and drawing the obtained undrawn fiber at a specific draw ratio. CONSTITUTION:A polyester containing ethylene terephthalate as main recurring unit (preferably polyethylene terephthalate) is melted and extruded through a spinning nozzle and the extrudate is taken up at a spinning draft ratio of >=2,500. The extruded fibers are collected at a position between the solidifying point of the fiber and the lubricating point, preferably at a position within 1m from the solidifying point and as close as possible to the solidifying point and the collected yarn is applied with a lubricant from both sides of the yarn. An undrawn yarn having an intrinsic viscosity of >=0.9 and a birefringence of >=0.07 can be produced by this procedure. The fiber is drawn at a draw ratio of >=2 to obtain the objective fiber. It is preferable to carry out the collection of the extruded fiber with a metering oiler to enable the simultaneous collection and lubrication of the fiber.
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