PulloffTest

PulloffTest is a standardized method used to quantify the adhesive strength between a coating, adhesive, or treatment and its substrate by pulling off a bonded dolly perpendicular to the surface until failure occurs. The test yields a pull-off strength, usually reported in megapascals (MPa) or pounds per square inch (psi), and a description of the failure mode.

In procedure, a circular dolly is adhered to the prepared surface using an epoxy or similar adhesive. After curing, a pull-off tester engages the dolly and applies a controlled tensile load at a prescribed rate until failure. The peak load divided by the dolly area gives the pull-off strength. The test is sensitive to surface preparation, dolly diameter, adhesive type, temperature, and curing time.

Standards and specifications associated with PulloffTest include ISO 4624 and ASTM D4541. These documents define dolly dimensions, surface preparation, loading rate, and how to classify failure modes: cohesive within the coating, adhesive at the coating-substrate interface, or substrate failure. The method is applicable to a wide range of coatings, paints, adhesives, and thin-film applications, and can be adapted for different substrates and environmental conditions.

Applications are widespread in coatings, automotive, aerospace, and construction sectors, where pull-off strength data support quality control, material selection, and research and development. Limitations include its localized nature, the influence of substrate heterogeneity, potential damage to the substrate, and the need for proper surface preparation and curing to obtain meaningful results. PulloffTest remains a practical, industry-standard tool for assessing adhesion performance.