ABSTRACT
Adhesion and cohesion are phenomena which may be described thermodynamically, but actually they cannot be measured precisely. It was shown that the most important bonding processes are bonding by adhesion and bonding with pressure-sensitive adhesives (PSAs). The function of PSAs is to ensure instantaneous adhesion upon application of a light pressure. Most applications further require that can be easily removed from the surface to which were applied through a light pulling force. The properties which are essential in characterizing the nature of PSAs comprise tack, peel adhesion, and shear. The latter will adhere to the substrate. The liquid adhesive layer of the PSAs working in the bond has to offer a controlled bond resistance The first measures the adhesive’s ability to adhere quickly, the second its ability to resist removal through peeling, and the third its ability to hold in position when shear forces are applied.
