The dependence of loop tack, peel strength and shear strength of SMR L and Epoxidized Natural Rubber
(ENR-25 and ENR-50)-based pressure sensitive adhesives on the rate of testing was investigated using
coumarone-indene as the tackifying resin. Toluene and poly(ethylene terephthalate) (PET) were used as
the solvent and substrate respectively throughout the study. A SHEEN hand coater was used to coat the
adhesive on the substrate. All adhesion properties were determined with a Llyod Adhesion Tester operating
at different rates of testing. Results show that loop tack, peel strength and shear strength all increase with
increase in rate of testing, an observation which is attributed to the viscoelastic response of the adhesive
which results in cohesive and adhesion failures at low and high test rates, respectively. Except for shear
strength, the other adhesion properties increase with adhesive coating thickness. ENR-25-based adhesive
consistently exhibits higher value compared to ENR-50 and SMR L. For shear strength, the largest value
measured is for ENR-50 adhesive system.