Short answer: a data sheet is a description of how a specimen behaved under one defined test, not a promise about your assembly. Most of the numbers are only comparable between suppliers when the test method is quoted with them — and the properties that decide whether you have a problem in production are usually the ones a TDS does not carry at all.
1. Peel adhesion: the number buyers over-trust
Peel adhesion is the figure most often used to rank quotes, and the one most easily misread. The result changes with every one of these:
- the substrate — steel, painted metal, PVC, XLPE, TPU, silicone, PP all give different values;
- the peel angle — 180° and 90° are not interchangeable;
- the speed of the pull;
- the dwell time between application and test — 20 minutes and 24 hours can differ substantially;
- the conditioning — temperature and humidity before and during the test.
A higher peel number is also not automatically better. On a harness that will be reworked, or on a surface that must come away clean, an aggressive adhesive is a liability. Decide what the bond has to do first, then read the figure.
2. Tensile strength and elongation: a pair, not two separate numbers
Tensile strength tells you the force at which the backing breaks; elongation tells you how far it stretches first. Read them together. A high tensile with very low elongation means a backing that holds load but will not conform over a branch point. A high elongation with modest tensile stretches around shapes but can creep back and open an overlap under tension.
For hand application, the useful question is not the laboratory tensile but whether the operator can tear it cleanly and straight without a blade — a property that depends on the weave direction and finish, and which rarely appears as a number.
3. Thickness: a tolerance, not a value
Total thickness on a TDS is a nominal figure. What matters in production is the tolerance around it and where the measurement is taken — backing only, or backing plus adhesive. Two consequences buyers meet regularly:
- in a winding slot or a tight stack-up, a tape at the top of its tolerance band stops the assembly fitting;
- on a die-cut part, thickness variation shows up as inconsistent cut quality and liner release.
Ask for the tolerance and the measurement method, not just the nominal number.
4. Temperature ratings: for how long, and measured how?
A temperature figure on its own is close to meaningless. The questions that make it usable:
| Ask | Why it changes the answer |
|---|---|
| Continuous or short-term? | A tape that survives 30 minutes at a peak is not rated for weeks at that temperature |
| For how long was it exposed? | Automotive specifications typically state hours (for example 3000 h) alongside the temperature |
| What was measured afterwards? | Adhesion retention, backing integrity, discolouration and residue are different acceptance criteria |
| On which substrate? | Ageing against a cable jacket can differ from ageing in free air |
5. Standards named on a TDS are not the same as certification
"Tested to", "complies with", "Listed" and "Recognized Component" mean four different things, and only the last two involve a certification body's file. If a data sheet names a standard, ask which applies:
- an internal test using the method of a standard — useful, but it is the supplier's own result;
- a third-party test report — independent, but tied to one specimen and construction;
- a certification file — carries a number you can look up, with a defined scope.
Our own example: EJOY's group manufacturer holds UL Recognized Component file E544340 under ANSI/CAN/UL 510A, and that file covers tape type Z1V020. It is not a statement about every grade in the range, and we do not present it as one. Expect the same precision from any supplier.
6. What a data sheet never tells you
These decide whether a tape works in production, and none of them are on a TDS:
- how it behaves on your substrate after your cleaning process;
- unwind force at your line speed, and whether the roll telescopes;
- flagging at the end of a wrap after a thermal cycle;
- edge fray and lint on a die-cut part;
- how it is removed, and what it leaves behind, six months later;
- lot-to-lot consistency — one good roll proves nothing about serial supply.
7. A short checklist before you compare quotes
- Ask every supplier for the test method behind each number you intend to compare.
- Normalise the substrate — insist on figures measured against the material you actually use.
- Separate certification facts (file number, scope) from test results (method, specimen).
- Ask for the thickness tolerance and the lot-traceability reference.
- Qualify the shortlist on your own part. Lab data narrows the field; it does not approve a supplier.
FAQ
Can I compare peel figures from two suppliers?
Only when both quote the method: substrate, angle, speed, dwell and conditioning. Otherwise you are comparing different tests.
What does a temperature rating mean?
That a specimen survived a stated time under stated conditions. Ask whether it is continuous or short-term, how long, and what was measured afterwards.
Is thicker stronger?
No. Strength comes from the backing construction; thickness affects fit, conformability and edge behaviour.
What is missing from every TDS?
Behaviour on your substrate, at your line speed, after your thermal cycle — and lot-to-lot consistency.
Next: how to qualify a tape supplier, total cost of ownership, or the selection guide. For MOQ, samples and lead times see sourcing.