Experimental study of viscoelastic effects on the adhesion strength of PSA tapes

Abstract

The evaluation method of adhesion strength of PSA (pressure sensitive adhesive) tapes has been extensively investigated because of their demand especially in electronics field. In this study, we focus on separation energy of PSA tapes measured from conventional peel test and probe tack test. Assuming separation force is consumed for making new surface, we can simply calculate the separation energy from both tests. In peel test, separation energy was calculated from the energy conservation between the work of external force and surface energy generated on peeled area. In probe tack test, it was calculated by subtracting strain energy of PET substrate from the work of external separation force. The separation energies obtained from these tests were compared in terms of strain rates of PSA layers during separation process from movies taken by high speed microscope. PSA tapes of different visco-elastic properties were prepared by changing the amount of the cure agent in order to also investigate the influence on the separation energy. As a result, it was found that the separation energies obtained from these tests are identically determined despite different separation process, but further investigation is required for calculation of strain rate for large elongation of PSA layer.