pulloffadhesietesten

Pulloffadhesietesten are standardized methods used to quantify the adhesive strength between a coating or layer and its substrate. The tests determine the force required to detach a bonded dolly from the coating under perpendicular loading, providing a measure of how well the coating adheres in a given condition. They are commonly applied in coatings technology, construction, automotive, and quality control to assess adhesion of paints, varnishes, sealants, or other surface treatments on metal, concrete, wood, and composites.

Principle and output: A circular dolly or stud is bonded to the coating surface with a high-strength adhesive. After curing, the dolly is pulled away from the surface along the normal to the substrate. The maximum pull-off force F is recorded, and the pull-off strength is calculated as F divided by the dolly area, expressed in MPa. The test also documents the failure mode, such as adhesive failure at the coating-substrate interface, cohesive failure within the coating, or substrate failure.

Procedure considerations: Surface preparation (cleaning and roughening), choice of adhesive, dolly size, and pulling rate influence results. Environmental conditions and coating thickness also affect outcomes. The test is destructive at the tested location, so multiple tests may be performed to obtain representative data. Careful interpretation is required, as results reflect local adhesion under the specific test conditions.

Standards and applications: The method is described in international and national standards, including ISO 4624 and related EN standards. It is widely used to verify adhesion after application, curing, or exposure to service conditions, supporting quality control and material qualification in various industries.