Viscosity, Shear Strength, and Peel Strength on Poly(ethylene terephthalate) of (Natural Rubber)-Based Adhesives Containing Hybrid Tackifiers

摘要

The viscosity, shear strength, and peel strength of [natural rubber (Standard Malaysian Rubber (SMR) L grade)]-based pressure-sensitive adhesives were studied by using hybrid tackifiers, i.e., mixtures of coumarone-indene resin and petro resin. Toluene and poly(ethylene terephthalate) were used as the solvent and substrate, respectively. Viscosity of the adhesives was determined with a HAAKE rotary viscometer, whereas shear and peel strength were measured by a Lloyd adhesion tester. Results showed that the viscosity and shear strength decreased with increasing petro resin concentration, an observation which is attributed to the plasticizing effect of the resin. Peel strength, however, showed a maximum value at 60 phr (parts by weight per hundred parts of resin) petro resin concentration, thus indicating maximum wettability at this petro resin content. Peel strength increased with coating thickness for ail the peel tests studied. In all cases, a 90° peel test consistently exhibited the highest peel value.