Elastic Recovery Force
Stretch woven and knitted fabrics utilize synthetic polyurethane filaments that pull extended yarns back to their original dimensions after tensile tension is released. Elastane retraction measures the percentage distance or force with which stretch yarns contract following controlled extension. Garment manufacturers evaluate this recovery property to ensure form-fitting apparel maintains shape retention without permanent sagging.
Strain Hysteresis
Tensile testing instruments stretch fabric swatches to fixed extension limits, such as thirty percent, and measure pulling force during extension and relaxation cycles. The difference between extension force and recovery force demonstrates energy loss within the elastane core during wear. High retraction forces provide firm compression, whereas low retraction leads to fabric growth and bagging at knees and elbows.
Finishing Heatsetting
Stenter frame heatsetting sets the permanent baseline for elastane stretch and recovery behavior. Processing temperatures around one hundred ninety degrees Celsius stabilize polyurethane molecular chains while establishing target fabric width and weight. Improper temperature control degrades elastane filaments, causing loss of elasticity and uneven fabric shrinkage.
Garment Pattern Adjustment
Pattern makers apply negative tolerance allowances to garment dimensions based on measured retraction percentages. High retraction fabrics require smaller pattern templates to achieve intended body-conforming fit. Precise recovery testing prevents sizing errors in production batches.
