False twist-crimped polyester yarns production
AssigneeTeijin Limited
InventorsMorio Ikeda, Mamoru Tsumoto
Life of this patent
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Abstract
A false twist-crimped polyester yarn having a density (d) of 1.3800.ltoreq.d.ltoreq.1.3970 (g/cm.sup.3) and total percentage crimp (TC) of TC 30% is produced by false twisting a polyester multi-filament having a birefringence (.DELTA.n) of 0.030.ltoreq..DELTA.n.ltoreq.0.145 while heat setting the filament in the twisted state at 160.degree. to 210.degree. at a draft (dr) which satisfies the following equation: -150(.DELTA.n) + 17.ltoreq.dr.ltoreq.0.9 .times. 10.sup.4 (.DELTA.n.sup.2)-29 .times. 10.sup.2 (.DELTA.n)+248.
Claims3
A process for producing a false twist-crimped polyester yarn which comprises false twisting undrawn polyester multifilament yarn obtained by melt-spinning at a speed of 2500-5000m/min., having a birefrigence (.DELTA.n) of 0.030-0.145 and a density of not greater than 1.3720, while heat-setting said yarn in the twisted state at a first temperature of 160.degree.-210.degree.C, at a draft (dr) expressed by the equation:
- -150(.DELTA.n) + 17 .ltoreq. dr .ltoreq. 0.9 .times. 10.sup.4 (.DELTA.n.sup.2) - 29 .times. 10.sup.2 (.DELTA.n) + 248
- and then subjecting the false twist-crimped yarn to a second heat-setting temperature.
Dependencies are inferred from the claim text.