Modulus Setting It Correctly on a Tech Pack
Modulus should be written into the tech pack with a value, a tolerance and a method. This removes ambiguity from quotations.
Definition to agree
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.
Target value
Open the specification at 4-8 kPa at 30% extension, adjusted to the end use. 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.
Method line
Always pair the target with ISO 13934-1 modulus so the mill and the laboratory test the same way. 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.
Tolerance line
State plus or minus limits to keep production realistic while protecting the requirement. 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.
Approval step
Approve the result on pre-production bulk rather than on development fabric only. 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.
