PSA Release Force Profiles from Silicone Liners: Probing Viscoelastic Contributions from Release System Components

Release force profiles of an acrylic- and rubber-based pressure sensitive adhesive (PSA) from silicone release coatings containing different levels of a high-release additive (HRA) were measured. The profiles of release force differed dramatically for the two different adhesive types. The general trends of either increasing or decreasing release force profiles with peel rate were predominantly attributed to the relative ability of the adhesive component to dissipate and store energy (i.e., tan δ) over the operating frequency range. The addition of HRA enhanced the dissipative character (G″ and tan δ increased) of the release coating which resulted in higher release forces. An empirical model based on the viscoelastic properties of the adhesive and release coating was proposed to describe release force profiles and initial estimates for the fitting parameters were determined. The release model was shown to predict successfully the impact of adhesive thickness on the release force profile using an acrylic PSA which was not used for the model development. Some evidence was also obtained for the validity in omitting the contributions of the elastic backing components from the model.