Two rolls of PU leather can carry the same thickness and behave differently, because the figure that matters is not the nominal value but where the process sits inside the tolerance.
What thickness actually controls in PU leather
Handle and fold behaviour. Under 0.6 mm the material creases sharply and cracks.
That makes it a design decision rather than a purchasing one, which is why changing it after the product is fixed costs more than changing the material.
For PU leather, the working range is 0.5-1.5 mm. Inside that band the choice is commercial; outside it, the product changes category and so does the price.
What 0.5-1.5 mm does not tell you
| Position | Value | Effect on PU leather | Where it shows up |
|---|---|---|---|
| Floor | 0.5 | Lowest cost, least margin for process variation | Hydrolysis within a season |
| Working middle | 0.5-1.5 mm | Predictable performance at a normal price | Nothing to negotiate, nothing to explain |
| Ceiling | 1.5 mm | Best performance, highest cost | Cost the end product may not recover |
Buyers default to the floor because it is the cheapest compliant answer. That is rational until the first claim, and then the saving is measured against a replacement shipment.
The figure that decides the outcome is not thickness itself but the tolerance around it. A supplier who quotes 0.5-1.5 mm without a tolerance has not quoted a specification, and the first lot will define the tolerance for you.
How to measure thickness
The reference method here is Peel strength, run to ISO 2411, with an acceptance of >= 6 N/50 mm. The method is the easy part; sampling and conditioning are where reports diverge.
Measure on the goods as delivered, not on the greige or the pre-finished material. The figure that matters is the one in the product your customer receives.
Record the measured value rather than pass or fail. A marginal pass on thickness tells you the process is running at the edge, which is the information you need before the next lot rather than after it.
Thickness does not stand alone
Thickness moves with backing (knitted / woven / non-woven) and with peel strength (>= 6 N/50 mm). Tightening one usually costs money in another, and a supplier who accepts every tolerance without comment has either not understood the interaction or is planning to substitute.
This is why a specification written as a list of independent tolerances is weaker than one written as a construction. The list lets a supplier satisfy each line while missing the product.
The clause to write for thickness
The line below is the version we can quote against without inventing anything. Thickness appears with a tolerance and a test, not as a standalone number.
PU leather, 1.0 mm +/- 0.05, knitted backing, peel >= 8 N/50 mm, hydrolysis-resistant, 30 000 Martindale, cold flex -20 C 30 000 cycles, release-paper grain, Pantone 19-1016 TCX
Write it once and reuse it. The buyers who avoid claims are not stricter than everyone else; they send the same well-written clause every time.
When thickness goes wrong
Hydrolysis. The surface turns tacky and peels after months in a hot, humid warehouse or in service.
The cause is usually ester-based pu plus moisture plus heat. it is a chemistry problem, not a coating weight problem.
The test that catches it: 70 C / 95 % RH for 7 days, then peel strength and hand assessment.
What to specify instead: Specify hydrolysis-resistant (polyether or modified) PU and ask for the ageing report, not just the initial peel value.
None of this is visible in a quotation. It becomes visible in a retained sample and a lot record, which is why the paperwork matters more than the price on this parameter.
Four questions about thickness, before you order
- What tolerance do you hold on thickness, and what did your last three lots measure against it?
- Which method do you use for peel strength, and which laboratory signs the report?
- When thickness falls outside 0.5-1.5 mm, do you rework, downgrade, or ship and hope?
- Which of backing or peel strength would you move first to hit a lower price?
The answers are more useful than a certificate, because they show whether the process is controlled or merely inspected. Full ranges for PU leather are on the product page, and the measurement regime is described on the quality control page.
Questions buyers ask before ordering
What is the difference between hydrolysis-resistant and standard PU?
Standard ester-based PU absorbs moisture and breaks down from the inside. Hydrolysis-resistant grades use a different polyol and survive years in humid conditions. Ask for the 70 C / 95 % RH report.
Can PU leather be sewn like real leather?
Yes, with a leather needle, longer stitch and a roller foot. The risk is seam slippage on non-woven backing, so specify knitted or woven for sewn goods.
Three questions, and the answers that separate mills
If the PU leather figures on this page is going to be decided on a call, take these three questions into it.
| Question | Answer that should worry you | Answer that holds up |
|---|---|---|
| Which test catches hydrolysis? | “We have never had a complaint.” | Abrasion — on the production lot, with the acceptance figure written into the report and not into the email. |
| May I see a report for a lot you shipped last month? | “That is confidential customer information.” | A redacted report, which carries every number that matters and none of the customer’s identity. |
| Where in the 0.5-1.5 mm band will this order sit? | “In the middle, normally.” | A stated target and the readings behind it. Thickness drifting inside the band is how a conforming lot still fails. |
Failure modes, and the test that catches each one
A specification only earns its keep if it names the failure it prevents. These are the two that matter for the PU leather figures on this page.
| Failure | What triggers it | Test to demand on the production lot |
|---|---|---|
| Colour transfer | Excess pigment on the surface and insufficient topcoat. | Cold flex — ISO 7854 / -20 C; acceptance >= 30 000 cycles |
| Hydrolysis | Ester-based PU plus moisture plus heat. It is a chemistry problem, not a coating weight problem. | Colour fastness to rubbing — ISO 105-X12; acceptance >= grade 4 |
The other two, with acceptance numbers attached, are in the full failure analysis for PU leather. A supplier who cannot name the mode he sees most often is describing a catalogue, not a process.
Need thickness specified and tested against your end use?
Send the end use, the quantity and the destination market, and we will come back with a specification that meets it, a price at your volume and the test reports that back it up. Samples are free for qualified programmes; we charge the courier only.
Related reading
Sample cut with your values on it · Neutral packing and private label · Consolidation, documents and lead times
