Abstract
The apparatus which can observe the top and side views of stringiness behavior of pressure-sensitive adhesive (PSA) was prepared. The stringiness behavior of the acrylic PSA was observed with wide range of peeling load for some adherends having different critical surface tension (γc).The peel rate of each peeling can be measured using the apparatus. The peeling load for the peeling rate of 0.02 mm/s was measured for each PSA, and the value was showed as "Load (0.02)". That is, the peeling rate obtained by the constant load peeling measurement is able to be converted into the peeling load having the same unit as the adhesion force by this method. The Load (0.02) increased with the γc of adherend, however the contribution of γc to the Load (0.02) was found to be very low. On the other hand, the good correlation was obtained between the Load (0.02) and the width of saw-teeth shaped stringiness (R2 = 0.89) .It was found that the shape of stringiness is strongly dependent on the interfacial adhesion force and the mechanical properties of the PSA, the base material of tape and the adherend. And the interfacial adhesion force is affected by the wettability of PSA and adherend (γc), and the surface morphologies of PSA and adherend. Although the γc is a major factor, it is not all.
