A mass flow analysis of the conventional double-heater false-twist process shows that the yarn thermal shrinkage over the first heater equals exactly the imposed first overfeed. A relationship is derived between the yarn " mechanical shrinkage," thermal shrinkage over the second heater, and the imposed second overfeed. Single-heater results are shown to result from a special case of the more general analysis. Some supporting experimental results are given.
Get full access to this article
View all access options for this article.
References
1.
Backer, S. and colleagues, Mechanics of Texturing Thermoplastic Yarns. Part I:, Textile Research J.46, 599-610 (1976); Part II:, 46, 724-733 (1976); Part III:, 46, 802-809 (1976); Part VI:, 48, 198-218 (1978); Part VII:, 48, 722-732 (1978); Transient Threadline Behavior in False-Twist Texturing, J. Textile Inst.67, 224-226 (1976).
2.
Brookstein, D. and Backer, S., Mechanics of Texturing Thermoplastic Yarns. Part V: Steady-State Mechanics of Draw Texturing, Textile Res. J.47, 256-266 (1977).
3.
Familant, H.M. , Dependence of Latent Crimp on Wind-Up Tension in the False-Twist Texturing Process, Textile Research J.47, 448-449 (1977).
4.
Gupta, V.B. and Natarajan, M., Latent Crimp in False-Twist-Textured Polyethylene Terephthalate Yarn , Textile Research J.46, 417-419 (1976).
5.
Quynn, R.G., TheFalse-Twist Texturing of Various Fibres, J. Textile Inst.62, 510-511 (1971).
6.
Ribnick, A., The ThermalShrinkage of an Oriented Polyester Yarn as a Function of Time, Temperature, and Stress, Textile Research J.39, 742-748 (1969).
7.
Skelton, J., TheEffects of Planar Crimp in the Measurement of the Mechanical Properties of Fibres, Filaments, and Yarns, J. Textile Inst.58, T533-556 (1967 ).
8.
Textile Research Institute, " Stability of Crimp and Mechanical Properties of Textured Polyester Yarns to Solvent Treatments," Notes on Research No. 226, Princeton, N. J., November 1972.
9.
Thwaites, J.J. , Mechanics of Texturing Thermoplastic Yarns. Part IV: The Origin and Significance of the Torsional Behavior of the False-Twist Threadline, Textile Research J.46, 886-892 (1976) ; Thwaites, J.J., Brookstein , D.S., and Backer, S., Deductions about the False Twist Process from Observations of the Variation of Torque on Detwisting a Twisted Heat Set Yarn, J. Textile Inst.67, 183-186 (1976).
