Fraunhofer Institute for Microstructure of Materials and Systems IMWSReliable adhesive bonds are essential for numerous applications in the automotive, aviation, and construction industries. To ensure the quality and long-term durability of such bonds, we at Fraunhofer IMWS carry out specialized peel tests—including the bead peel test, which enables a particularly practical evaluation.
What is the bead peel test?
The bead peel test is a mechanical test in which the adhesion of an adhesive to a specific substrate – e.g., painted sheet metal, glass, or plastic – is evaluated by manually peeling off a bead of adhesive. The bead peel test is not standardized by an international standard such as DIN, ISO, or ASTM, but is based on industrial requirements and internal factory standards. Tests can be carried out according to company-specific specifications or in accordance with existing standard procedures.
The adhesive bead is applied to the test substrate in a defined geometry (e.g., triangular shape), allowed to cure, and then peeled off at a constant angle and with uniform tension. The evaluation is based on the fracture pattern (cohesive). triangular shape) on the test substrate, allowed to cure, and then peeled off at a constant angle and with uniform tension. The assessment is based on the fracture pattern (cohesive, adhesive, mixed fracture), which allows the quality of the adhesion between the adhesive and the substrate to be analyzed precisely.
Our advantages for you
Practical evaluation: The test simulates real-life loads, e.g., when bonding vehicle windows or body parts.
Versatile materials: We test on painted sheet metal, plastics, glass, glass ceramics, CFRP, aluminum, and more—even with different pretreatments (e.g., primer, plasma).
Standard-compliant and flexible: Testing is tailored to your individual requirements, e.g., for approval tests or damage analyses.
Direct applicability: Our results support your material approvals, quality assurance processes, and product developments.
Climatic stress – tested under realistic conditions
We also offer the following services for evaluating aging resistance:
- Condensation storage (according to DIN EN ISO 6270-2) – simulates long-term exposure to humidity at 40°C and 100% relative humidity.
- Climate change test – cyclic temperature and humidity changes to assess robustness under real environmental condition.
These climate pretreatments are carried out specifically before the peel test in order to evaluate adhesion strength and fracture behavior under stress in a comparable and practical manner.
Application examples
- Evaluation of the adhesion of cold-curing, elastic adhesives in car body construction
- Testing of repair bonds under climatic influences (condensation, etc.)
- Adhesive development and optimization for series or special applications