Characterization of advancing contact behavior of pressure sensitive adhesives coated on flat sheets

摘要

Pressure sensitive adhesives (PSAs), which are often coated on thin backing layers to form labels and tapes, are challenging to characterize mechanically. The adhesion behavior of PSAs are often assessed via peel and shear tests. However, these tests only measure the fracture behavior of the adhesives and the measured values are strongly influenced by viscoelastic dissipation and creep in the adhesive layer. These tests provide a measure of the separation behavior of the PSA and do not provide information on the adhesion energy driving the formation of the interface. Furthermore, because of the significant role that the viscoelastic properties of the adhesive play in these tests, it is difficult to obtain information on the fundamental work of adhesion of the PSA-surface interface. The JKR test offers the opportunity to measure adhesion during both the formation and separation of the contact, but the finite thickness and low modulus of the PSA makes it difficult to apply the traditional JKR analysis. In order to fully characterize the adhesive properties of PSAs, an alternative technique is needed.