Polyethylene terephthalate filament having high tenacity for industrial use
A polyethylene terephthalate monofilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3, which gives a stress-strain curve exhibiting an elongation of less than 2.5% at an initial stress of 2.0 g/d, with an initial modulus value of 80 to 160 g/d, an elongation of 7.5% or less in a stress range of from 2.0 g/d to 9.0 g/d, and an elongation of at least 2.0% or more in a stress range of from 10.0 g/d to the point of break, is provided.
1. A process for preparing a polyethylene terephthalate monofilament comprising the steps of:
spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3 through a nozzle having 192˜384 orifices, passing the spun yarn from the nozzle through a hood heater adjusted to 350˜400° C. and extended to 320˜500 mm,
quenching the yarn from the hood heater,
oiling the quenched yarn, and drawing in a multistep process using a plurality of godet rollers on which the contact areas between the yarn and the second godet rollers for the primary drawing is adjusted to 4,000˜8,000 mm 2 and the contact areas between the yarn and the third godet rollers is adjusted to 14,000˜18,000 mm 2 for the secondary drawing,
wherein the contact area is determined by the following equation:
contact area=average yarn width×number of turns×radius of godet rollers×2,
wherein the polyethylene terephthalate monofilament so produced gives a stress-strain curve exhibiting an elongation of less than 2.5% at an initial stress of 2.0 g/d, with an initial modulus value of 80 to 160 g/d, an elongation of 7.5% or less in a stress range of from 2.0 g/d to 9.0 g/d, and an elongation of at least 2.0% or more in a stress range of from 10.0 g/d to the point of break.
2. The process according to claim 1 , wherein the linear density of the polyethylene terephthalate is 3 to 30 denier.