English Abstract
Fundamentals and Mechanical Properties of PSA Tapes 4. Morphological Analysis at Peeling PSA Tapes - Part 2
Yoshiaki Urahama
Yamagata University Venture Business Laboratory, Japan
Nippon Gomu Kyokaishi, (2004), 77(5), 186-191 General Review in Japanese.

The unknown factors governing interfacial separation in cross-linked polymer adhesives at low pulling rates as demonstrated by their stringiness phenomenon are investigated.
Cohesive failure and adhesive/substrate interfacial separation of uncross-linked polymer adhesives have been adequately explained. However, in lightly cross-linked polymer adhesives, where cohesive failure cannot occur because there is no viscous flow, there are two regions of interfacial separation at low rate and this phenomena cannot be readily explained by present viscoelastic theories.
Investigation of the stringiness phenomenon of peeling pressure-sensitive adhesive tapes at constant loads shows that two peeling speeds exist for any peeling load up to the vicinity of 200g/25mm. Also it is clear that stringiness structure differs greatly at each peeling speed. The stringiness phenomenon of each of these two regions is analyzed using Miyagi's observation apparatus. These two measurements are then reversed and a comparison shows that the two peeling speeds correspond to each steady peeling region.
This field of investigation, when added to the present viscoelastic property studies should lead to a new peeling adhesive theory, which in turn will lead to the development of new high peel force pressure-sensitive adhesives.

Pressure sensitive adhesive, Stringiness phenomena, Stick-slip, Peel, Honeycomb structure, Sawtooth shape structure