Effect of Silica Filler on Viscosity, Peel Strength, Shear Strength and Tack of Styrene-Butadiene Rubber-Based Adhesive

Viscosity, peel strength, shear strength and tack of styrene-butadiene rubber (SBR)-based pressuresensitive adhesive were studied using silica as the filler. The silica content was varied from 10-50 parts per hundred parts of rubber (phr). The tackifying resin, solvent and coating substrate used were gum rosin, toluene and poly(ethylene terephthalate) (PET) respectively. Viscosity of the adhesive was determined by a Brookfield Viscometer. Both peel strength, shear strength and tack were measured by a Lloyd Adhesion Tester operating at 10-60 cm/min. Results show that viscosity increases with silica loading due to the concentration effect. Peel strength, shear strength and tack passes through a maximum value at 20 phr silica loading, an observation which is attributed to the culmination of wettability at the optimum silica content. Peel strength decreases with the angle of testing at a fixed silica loading and coating thickness. Both peel strength, shear strength and tack increases with coating thickness and testing rates.