Hook-and-loop has two working strengths and they are not the same. Peel is the force that opens the pair along the edge — what a wearer does with a fingernail. Shear is the force along the plane — what a loaded strap or a closed cuff sees when it tries to slide. A tape that peels easily can still hold in shear. A tape that “feels strong” in the showroom can fail in shear on a 25 mm overlap. Specify both.
TrimGem treats peel and shear as the closure equivalent of a snap pull-off: method, width, and a remaining value after cycles and wash.
What a full pack includes
- Peel — hook from loop at a controlled angle.
- Shear — resistance to sliding in the plane of the join.
- Cycle life — open/close repeats, then peel/shear again.
- Environment — heat, humidity, UV, then the same strengths.
- Geometry — width, hook height, loop height, density.
- Fibre check — nylon vs polyester vs blend, if the invoice is vague.
Medical articles add ISO 10993 when they claim skin contact. That is not a substitute for peel.
A workable method (apparel scale)
Condition specimens (23 ± 2 °C, 50 ± 5% RH, often 24 h). Cut a stated width (25 mm is a common strip). Engage hook and loop with a defined roller load (trade examples use a ~4 kg roller) so the operator’s thumb is not the variable.
Peel: 180° separation, speed on the order of 300 mm/min, report average force as N/cm of width.
Shear: defined overlap (e.g. 25 × 25 mm), pull in plane at a lower speed (e.g. 100 mm/min), report N/cm².
Cycles: a machine, not an intern. Examples in the trade use a small preload and tens of cycles per minute. Stop at 5 000 or 10 000, then re-test. Remaining strength ≥80% (sometimes ≥85% after 5 000) is a common purchase language.
After wash: 25–50 domestic washes with a cap on peel loss (programs quote ≤10%). Hooks that break and loops that shed are failure modes, not “ageing character.”
Hold: a dead-weight hang (e.g. 1 kg, 1 h, no creep) is a simple screen for pocket flaps.
Width tolerance (±1 mm) and hook/loop height (±10% of nominal) belong on incoming inspection. Five specimens, mean, SD, CV; a CV above ~15% is a process problem.
Standards you will be handed: ASTM D5169 (peel of hook-and-loop), DIN 3415, GB/T 3903.21 (footwear touch tape), JIS L 1086, MIL-DTL-32188 on military programs. ISO abrasion methods (e.g. ISO 4649) get borrowed for rubbery backings. Pick one peel method and stay with it.
Chinese industry language for the family includes FZ/T 01096. Put the method on the PO so the lab does not invent a zipper test.
Grade talk (illustrative, not a law)
Purchase sheets sometimes band:
| Duty | Peel | Shear | Cycles |
|---|---|---|---|
| Consumer apparel | ≥2.5 N/cm | ≥15 N/cm² | ≥5 000, little drop |
| Industrial | ≥5 N/cm | ≥25 N/cm² | 10 000 |
| Extreme / specified military | ≥8 N/cm | ≥40 N/cm² | plus temperature |
Other public tenders ask for peel ≥5 N/cm, a milder shear (≥8 N/cm²), 5 000 cycles at ≥85% remaining, UV 1 000 h at ≥85% remaining and ΔE ≤ 3, tensile on the tape itself (≥800 N/5 cm), formaldehyde caps. Do not mix bands. Write the numbers that match the garment.
Failure mode matters: hook fracture, loop pull-out, or backing tear. Each points to a different mill fix.
Spec line
Hook type and fibre (previous note), width, then peel method + minimum, shear method + minimum, cycles + remaining %, wash remaining, and whether adhesive or sew-on. Kidswear and next-to-skin add a hook-sharpness / moulded-hook requirement. Without those lines, “strong magic tape” is a feeling. Feelings do not survive a first bulk lot.