Modulus Frequently Asked Questions
Short answers to the questions buyers ask most often about Modulus.
What does it mean?
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.
What value should be specified?
Start from 4-8 kPa at 30% extension and adjust for the end use of the garment. 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 is it tested?
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.
Why does it change between lots?
Process variables such as finishing temperature and elastane batch cause the normal spread of results. 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.
Can results be compared across suppliers?
Only when the same standard revision and conditioning are used; otherwise measurements are not equivalent. 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.
