Air Jet Spun Yarn Mechanics in Elastic Woven Fabrics
Air jet core-spun yarns deliver torque-free, pill-resistant elastic wovens by locking polyurethane filaments inside parallel staple cores bound by vortex wrappers.
Residual Torque
Latent Measurement
Internal energy remaining in a yarn after the spinning or twisting process causes the strand to spontaneously twist or snarl when tension is removed. This residual torque is a byproduct of the mechanical stresses applied to the fibres during the formation of the yarn. If left unmanaged, the force leads to spirality in knitted fabrics where the entire garment appears skewed or twisted.
Torque Determination
Determination of the magnitude involves suspending a fixed length of yarn and counting the number of turns it makes as it seeks a balanced state. A higher count of these turns indicates a higher residual torque within the structure. This test is performed in a controlled environment to ensure that humidity does not alter the behaviour of the natural fibres.
Thermal Correction
Steam setting or autoclaving provides the thermal energy needed to rearrange the molecular structure of the fibres and relax the internal stress. After this treatment, the residual torque is significantly reduced, making the yarn easier to handle during subsequent knitting or weaving. Properly conditioned yarn results in a stable fabric that maintains its shape after laundering.
Functional Impact
High-twist yarns for crepe fabrics require careful balancing to achieve the desired surface texture without excessive distortion.