| 摘要 |
PURPOSE: Super low shrinkage polyester yarn is capable of forming draw points uniformly among single yarns, reducing variation of physical properties of the yarns, reducing generation of lap on a drawing roller device and increasing workability. A manufacturing method thereof is provided. CONSTITUTION: After leaving a test sample at 25deg.C under state of 65% of relative humidity for 24hrs., length of the test sample measured under a condition of 20g is L0. After heating the test sample in an oven, inner temperature of the oven is 150deg.C, for 30min., length measured in the oven is L1. Dry heat shrinkage(ΔS)Super is defined the follow formula: ΔS = (L0-L1)/L0x 100. A low shrinkage polyester yarn has under 5% of dry heat shrinkage(ΔS) and under 0.20 of strength variation and dry heat shrinkage variation each. The super low shrinkage polyester yarn is obtained by drawing polyester undrawn yarn between a first drawing roller device(20) and a second drawing roller device(30). A draw point fixed roller(10) is installed ahead of the first drawing roller device(20). Predraw ratio between the first drawing roller device(20) and the draw point-fixed roller(10) is 1.02-1.10. In predrawing, temperature range of the draw point fixed roller(10) is 70-85deg.C adjacent to glass transition temperature of polyester.
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