Process Conditions Affecting the Physical Properties of Air-Jet Textured Yarns with PET/PTT Bicomponent Core and PET Effect Components

This study investigates the alterations in the physical properties of air-jet-textured yarn (ATY) produced using a poly(ethylene terephthalate)–poly(trimethylene terephthalate) bicomponent filament yarn as the core under varying processing conditions. The inherent crimp structure of the bicomponent fiber can yield elastic behavior, potentially resulting in the loss of loops formed during air-jet texturing. Fundamental properties, including tenacity, initial modulus, and instability, were analyzed using a specified measurement method tailored to the crimped core yarn. Additionally, a novel concept of loop density was introduced to evaluate loop stability. The physical properties of ATYs were predicted across various processing conditions within the conventional operational ranges using a statistical formula developed to illustrate the variation trends. To investigate loop stability, the concepts of loop density and loop density gap were introduced, and cyclic tensile tests were conducted. The increase in core yarn diameter and overall diameter was more significant than the increase in loop area, resulting in an overall decrease in loop density. The loop stability was preserved when density, overfeed, and air pressure were maintained at lower levels. The contributions of this study will enhance ATY production techniques and enable manufacturers to produce more stable and elastic yarns suitable for premium fashion applications, thereby meeting consumer preferences for cotton-like synthetic fabrics.