| 摘要 |
PURPOSE: A manufacturing method of polyethylene-2,6-naphthalate fiber having high strength, low shrinkage, 2.5-6denier of single yarn fineness, at least 1000denier of total fineness and high coefficient of variation(CV%) is characterized by using a spin oiling agent having low viscosity and using a low velocity spinning method and a radial in to out quenching method. A treated cord manufactured out of the polyethylene-2,6-naphthalate fiber has excellent dimensional stability and strength, and is useful for reinforcement of rubber products like a tire or a belt. CONSTITUTION: Polyethylene-2,6-naphthalate fiber is obtained by the steps of: (A) extruding spun yarn containing at least 85mol% of ethylene terephthalate unit and having 0.70-1.3 of inherent viscosity at 290-330deg.C; (B) passing the spun yarn through a delay-cooling area, followed by quenching the spun yarn with a radial in to out flow quenching method to solidify the spun yarn; (C) oiling the spun yarn at a distance of under 2m from an initial winding roller; (D) winding undrawn yarn at 200-1000m/min. of spinning velocity to make the undrawn yarn having 0.001-0.015 of birefringence; and then (E) multistage-drawing the yarn in a total draw ratio of at least 4.0. The polyethylene-2,6-naphthalate fiber has (1)0.6-1.0 of inherent viscosity, (2)at least 8.5g/d of strength, (3)at least 6% of elongation, (4)at least 0.35 of birefringence, (5)under 7.0% of coefficient of variation(CV%) of filament sectional diameter and (6) 1-4% of shrinking percentage.
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