Mechanics of Texturing Thermoplastic Yarns

Abstract

A model is proposed to reflect the steady-state interaction between material properties of POY feed yarn and the false-twist draw-texturing process. Free filament migration is assumed for initial cold twisting, resulting in equal cold filament strains over the yarn section. No migration is assumed to occur during threadline uptwisting at the heater entry. Threadline torque in the cold zone is attributed to filament bending, twisting, and tensioning, while at the heater entry only the tensile components of yam torque prevail. Numerical solutions of equations of equilibrium and continuity provide predictions of threadline tension, torque, and zone twists. Results of experiments on a laboratory texturing device show good agreement with numerical predictions based on the steady-state model. Limitations of the model are considered.