A high performance measuring system has been developed for holding-power analysis of pressure sensitive adhesive (PSA) tapes. Pre-load mechanism and wide dynamic range sensor (with 1μm resolution and 30mm displacement range) make it possible for this system to give displacement-time curves of dozens of samples simultaneously even if they have extremely different holding-power. Multiple measuring data can be acquired (with constant Δlog(t) interval), processed and stored by using multiplex data processing technique. Using this system we measured various PSA tapes and discussed the influences of testing conditions upon holding-power measurements. Difference of failure mode and progressing speed can be evaluated by analyzing displacement-time curves. We found that wide dynamic range sensor is essential to detailed evaluation of holding-power, and proved this measuring system is useful for analyzing failure process of PSA tapes in holding-power test.

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The surface modification of low density polyethylene (LDPE) sheet was carried out by corona discharge treatment using four different electrodes in shape, i.e., rod, groove, knife-like, and hemicylic electrodes. The adhesive strength was determined for the laminated film composed of LDPE with polyethylene-terephthalate (PET). The adhesive strength became strong when polymers were treated knife-like and hemicylic electrodes. It was also confirmed by XPS analysis that almost complete cohesive failure occurred in peeling test. Homogeneity of treatment was evaluated through peeled curve and the photograph in corona discharge. The treatment with hemicylic electrode led to be more homogeneous on oxygen content of LDPE surface than that with the other electrodes. The adhesive strength reached over 900 N/m when both of LDPE and PET were treated.

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