Debonding Mechanisms in Pressure Sensitive Adhesives With Composition Gradients

摘要

The effect of a composition gradient along the thickness in pressure sensitive films was investigated. The adhesion properties of bilayers films made from acrylic solutions or emulsions, one layer being more cohesive and the other more dissipative, were studied by performing probe tack experiments. In order to understand the mechanisms that determine the bulk and the interfacial contributions to the debonding, tests on different surfaces were carried out. The results show that the presence of a composition gradient can enhance the adhesive properties, particularly on a low energy surface like polyethylene. On steel the presence of the thin layer of a more elastic adhesive in contact with the adherent can influence significantly the debonding mechanism, transforming the fracture from cohesive to adhesive.