Organic cotton is prized for its softness, breathability, and sustainability, making it a favourite in period underwear, panties, and bras. However, high-stretch versions often shrink after high-temperature ironing, a common but preventable issue in production.
Why Does Organic Cotton Shrink Under Heat?
- Organic cotton fabrics are woven or knitted under tension during manufacturing.
- When exposed to high heat (like ironing or bonding), tension releases, and the fibres relax and contract.
- The result? Shrinkage is often 5–10%, especially in cotton-spandex blends used in stretch underwear.
Why Shrinkage Matters in Underwear Manufacturing
- Underwear that feels tight or uncomfortable
- Wavy seams and puckered hems
- Distorted garment shapes
- Inconsistent sizes across production batches
How to Prevent Shrinkage in High-Stretch Organic Cotton After Ironing High-Temperature
High-stretch organic cotton can shrink greatly when ironed at high temperatures, especially with bonding methods like fusible tape. To avoid sizing issues, pre-shrink the fabric with heat, let it settle, then cut based on the final size. Stitching is safe since it doesn’t involve heat, but bonding needs extra care.
Stitching vs. Bonding: Heat Sensitivity
Stitching (Safe Method):
- Uses thread, no heat involved
- No shrinkage problems
- Safe for organic cotton blends
Bonding (Risky Without Pre-shrinking):
- Involves heat adhesives, fusible tapes, or seam bonding
- Can cause the fabric to shrink or warp near the bonded area
- May result in wavy seams, uneven tension, and poor fit
Final Thoughts: Get the Fit Right, Every Time
Heat shrinkage can be challenging if you’re making period panties, sustainable lingerie, or simply working with organic cotton. Pre-shrinking the fabric and understanding how it reacts to heat helps ensure a better fit and fewer sizing issues.