Testing standard
Standard Test Method for 90 Degree Peel Resistance of Adhesives
Written and technically reviewed by Dak System Inc. engineeringLast reviewed
ASTM D6862 determines the peel resistance of an adhesive bond between one rigid and one flexible adherend at approximately 90 degrees. It is useful for acceptance and quality-control testing of structural adhesives, pressure-sensitive adhesives and laminates bonded to rigid substrates.
A flexible adherend is bonded to a rigid one, cured and conditioned, and the bonded width measured. The rigid adherend is mounted on a fixture whose platform travels horizontally, the free end of the flexible member is gripped, and the two are separated at a constant rate so that the peel angle stays at approximately 90 degrees throughout. The force over the steady portion of the peel — excluding the higher force needed to start it — is averaged and divided by the bonded width, and the way the bond gave way is recorded as percentages of each failure mode.
How firmly a flexible layer holds to a rigid substrate when peeled, as an acceptance and quality-control figure. What distinguishes this method from many peel standards is that it fixes the adherend thicknesses when the specification does not — 0,60 mm for the flexible member and 1,60 mm for the rigid one. That is worth understanding rather than skimming: part of the measured peel force goes into bending the flexible adherend around the peel front rather than into breaking the bond, so a thicker flexible member raises the value with no change in the adhesive at all.
The method fixes adherend thicknesses when the specification does not, which removes a variable that would otherwise move every result.
Adherend thickness changes the answer, because part of the measured force goes into bending the flexible member. Specifying defaults is how this method stops that variable floating.
Average force over the steady peel, divided by the bonded width
Force per unit width. The initiation peak is excluded because it reports how the tab was made.
Part of the force bends the flexible adherend rather than breaking the bond
A thicker flexible member takes more force to bend around the peel front, so it raises the measured value without the adhesive changing at all.
A 90 degree value does not convert to a 180 degree one
A light grip on the flexible adherend. The rigid adherend needs a travelling support so the peel angle stays at 90 degrees as the front advances — the fixture, not the frame, is what makes this test a 90 degree one.
SpecificationsSmall forces and a travelling platform. Peel forces here run from a few newtons to tens of newtons, so the load cell is chosen for the force rather than the frame — a cell sized for the machine is working below the range its accuracy class describes. The 90 degree fixture is not optional: with a fixed panel the peel front advances along the substrate while the grip stays put, so the angle opens as the test runs and the result becomes an average over a drifting geometry.
Peeling against a fixed panel, so 90 degrees is only true at the start. Omitting the adherend thicknesses from the report, when they are part of the measurement. Quoting a peel value without its angle, when a 90 degree and a 180 degree figure are different numbers for the same bond with no conversion between them. Including the initiation peak in the average, which reports how the tab was made. And reporting a force with no failure mode, when adhesive, cohesive, adherend and transfer failures call for entirely different responses.
| ASTM D6862 — 90 degrees | ISO 8510-2 — 180 degrees | |
|---|---|---|
| Angle | Approximately 90 | 180 |
| Adherends | One rigid, one flexible | One rigid, one flexible |
| Fixture | Travelling platform | Fixture holding the rigid member |
| Convertible | No | No |
The same specimen type at two angles, giving two different numbers. Peel resistance depends on angle because part of the force bends the flexible adherend, and that share changes with the geometry.
It is the ASTM 90 degree peel test for adhesives, measuring the resistance to peel of a bond between one rigid and one flexible adherend. It is intended for acceptance and quality-control testing, and is used for structural adhesives, pressure-sensitive adhesives and laminates bonded to rigid substrates. The current designation is ASTM D6862-11(2021).
Because adherend thickness changes the result and would otherwise float between laboratories. Part of the measured peel force goes into bending the flexible member around the peel front rather than into breaking the bond, so a thicker flexible adherend raises the value without the adhesive being any better. Fixing 0,60 mm for the flexible member and 1,60 mm for the rigid one when nothing is specified removes that variable.
To keep the angle at 90 degrees. With a fixed panel the peel front moves along it while the grip stays put, so the angle opens progressively and the recorded value becomes an average over a changing geometry. A platform that travels horizontally as the strip comes off holds the angle where the method says it is — the fixture, rather than the frame, is what makes this a 90 degree test.
No. Peel resistance depends on the angle because the share of the measured force that goes into bending the flexible adherend changes with the geometry. There is no general conversion, which is why ISO 8510 has separate parts for 90 and 180 degrees and why a peel value quoted without its angle cannot be checked against anything.
Because starting a peel takes more force than continuing one, and the excess depends on how the unbonded tab was formed rather than on the adhesive. Including it reports the specimen preparation. Peeling far enough to establish a steady trace and averaging only that portion is what makes the value a property of the bond.
Because the modes have different consequences and the force cannot distinguish them. A cohesive failure through the adhesive says the adhesive was the limiting element. An adhesive failure at the interface says the surface preparation was. Adherend failure says the bond outlasted the material. Transfer leaves residue on the customer's part. Reporting percentages of each is what makes the number actionable.
A small one. Peel forces here are commonly a few newtons to tens of newtons, and an accuracy class applies only down to a stated fraction of capacity — so a cell sized for the frame is working outside the range its certificate describes and produces a plausible trace with no traceable accuracy behind it.
Dak verifies against whichever standard the method names, and where a class applies our frames sit a class tighter than it asks.
| The method asks for | Dak supplies | |
|---|---|---|
| Capacity | Low — 90 degree peel forces are commonly a few newtons to tens of newtons | Load cells from 1 kg to 60 ton on the Series 7200, and 0.5 to 100 kN on the Series 9000 |
| Force accuracy | Verified at the actual peel force, not at frame capacity | ISO 7500-1 Class 0.5, verified to ASTM E4, DIN 51221 and BS 1610 |
| Gripping | A 90 degree peel fixture holding the rigid adherend on a travelling platform | Our peel and adhesion fixtures, built to the specimen |
| Environment | 23 ± 2 °C standard laboratory atmosphere | 3009 series chambers, −150 °C to +400 °C — temperature only |
This page describes the method as practised. The governing text is the current edition from the issuing body. Tell us what you are testing and we will answer with the machine, the fixture and a quotation.
