Pressure sensitive adhesive rate dependence

The optimal adhesive layer thickness depends on a number of factors. Some bonds, notably Tensile test specimens, are stronger when the adhesive layer thickness is redn-ced. For fracture specimens, including double cantilever beam specimens bonded with structural adhesives (see Fracture mechanics test specimens), optimal bond thicknesses have been identified, although the optimal thickness depends on the loading rate and test temperature. " Enhanced ductility plays a role in this process, and a sufficient quantity of adhesive is desired to dissipate energy (see Peel tests). This latter mechanism is also important in the peel energy of Pressure-sensitive adhesives and other systems. 

The viscoelastic contribution to the fractnre energy in an adhesion test is, in principle, rate and temperatnre-dependent. Where this contribution is significant, it has been possible to nationalise adhesion measurements using the WLF transform-see Adhesion - fundamental and practical. Pressure-sensitive adhesives - adhesion properties and Tensile... 

Most adhesive tapes are composed of a flexible backing (paper, plastic, cloth, metal foil, etc.) to which a pressure-sensitive adhesive has been applied to one side (both sides for double-sided tapes). Pressure-sensitive adhesives typically consist of a rubbery material with a modifying tactifier that may be applied to the tape by a solvent system, hot melt, or by other means. One would expect such materials to be sensitive to the mode of stress (tensile versus shear) in the region where debonding occurs. Furthermore, since tacky rubbers of the type used in pressure-sensitive adhesive are viscoelastic, one would anticipate material properties to be time- and rate-dependent. Are these expectations consistent with the observations from your simple peel test ... 

Rate and Temperature Effects for Pressure-Sensitive Adhesives. Pressure-sensitive adhesives consist of soft elastomeric semi-solids. Their peel strength depends strongly upon the rate of peel and the test tem-... 

A pressure-sensitive adhesive (PSA) is a imique material in that it displays characteristits that are neither liquid nor solid but a combination of both that depends on the rate of stress application. Some of the characteristics of a PSA that are described by the Pressure Sensitive Tape Council are the following ... 

D-2556. Test Method for Apparent Viscosity of Adhesives Having Shear-Rate-Dependent Flow Properties. D-2979. Test Method for Pressure-Sensitive Tack of Adhesives Using an Inverted Probe Machine. ... 

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