Method for manufacturing sewing thread

Abstract

A method for manufacturing a sewing thread comprising the following steps: drawing an undrawn polyester multifilament yarn; preliminarily heat treating the drawn yarn at an effective heat treating temperature before false twisting; then, false twisting the heat treated synthetic multifilament yarn at a temperature of at least 150.degree. C.; subjecting the false twisted yarn to a fluid jet treatment under the slackened condition so as to intermittently interlace in a lengthwise direction constituent filaments of the yarn and so as to form protruded portions protruding from the surface of the yarn; and post-heat treating the interlaced yarn at an effective heat treating temperature being higher than the heat treating temperature of the false twisting. By this method, a thread suitable for sewing can be obtained. The produced sewing thread comprises at least one synthetic multifilament yarn, in which thread constituent filaments of the multifilament yarn are intermittently interlaced along the lengthwise direction thereof, and a part of the constituent filaments of the multifilament yarn is protruded from the surface of the multifilament yarn; and the torque of the sewing thread is very small in spite of the fact that substantially all filaments constituting the sewing thread have been subjected to the same false twisting.

Dependencies are inferred from the claim text.