Method for heat treating a synthetic yarn during false-twist texturing and a method for rethreading a yarn

摘要

A method for rethreading a yarn during false twist texturing of the yarn includes setting the temperature of a heater body outside a range having upper and lower limits so that if melted yarn adheres to the heater, the yarn vaporizes quickly if the temperature is above the upper limit or is easily removed by rethreading the yarn if the temperature is below the lower limit. The heater body has a total length between 0.8 and 1.2 m, the heater body and heating member divided into two pieces from upstream side to downstream side of the heat treating apparatus in ratio of length between 1:3 and 1: 1:5. The divided upstream heating member (12) is able to heat the upstream heater body (11) at a temperature higher than 370 DEG C., and the downstream heating member (22) is to heat the downstream heater body (21) at a temperature of between 200 DEG and 320 DEG C. or higher than 370 DEG C. The upstream heater body has yarn guides (15) disposed at a longitudinal pitch of at most 30 mm, and the downstream heater body has yarn guides ( 24) disposed at a longitudinal pitch between 80 and 120 mm.