Process and apparatus for producing easily dyeable polyester false-twisted yarns

Abstract

A false-twisted polyester yarn of good dyeing and mechanical properties is produced by a process wherein a yarn consisting of an as-spun polyester fiber having a mean birefrigence index (.DELTA.n) of from 15.times.10.sup.-3 to 150.times.10.sup.-3 is heat-treated and continuously, subjected to a false twisting treatment or draw-false twisting treatment. A preferred apparatus used comprises a feed yarn creel, a false twisting heater and an optional stabilizing heater, a false twisting element and a winder, wherein a heat-treating heater of the non-contact type is arranged upstream of the false twisting heater and between the false twisting heater and the feed yarn creel, at a height substantially equal to the height of the feed yarn creel so that the heat-treating heater confronts the false twisting heater; and a yarn cooling zone is provided between the heat-treating heater and the false twisting heater.

Dependencies are inferred from the claim text.