Modulus Why Shipments Get Rejected Over This
Many disputes come down to Modulus. Below is what inspectors check and why shipments fail.
The core definition
force required to reach a given extension. Working figures for Modulus normally sit around 4-8 kPa at 30% extension in mainstream production. Note ISO 13934-1 modulus on the tech pack so nobody tests against an older revision.
Most common cause of failure
Results usually fall outside 4-8 kPa at 30% extension because the target was never written into the order. Record elastane content alongside Modulus, because blends shift the measured value. A result outside 4-8 kPa at 30% extension usually points to process drift rather than to the fibre itself.
How it is checked
Inspection and laboratory work both refer to ISO 13934-1 modulus. Keeping reference values for Modulus lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 13934-1 modulus, since both affect the reading.
Related faults
it defines support level in compression fabric, so related complaints often point back to this single parameter. Working figures for Modulus normally sit around 4-8 kPa at 30% extension in mainstream production. Note ISO 13934-1 modulus on the tech pack so nobody tests against an older revision.
Avoiding rejection
Agree targets, tolerances and the method before production, then test per lot rather than per shipment. Record elastane content alongside Modulus, because blends shift the measured value. A result outside 4-8 kPa at 30% extension usually points to process drift rather than to the fibre itself.
