Effect of Sodium Sulfate on the Viscosity, Tack, and Adhesion Properties of SMR 10-based Pressure-sensitive Adhesive

The effect of sodium sulfate as filler on viscosity, tack, and adhesion properties of Standard Malaysian Rubber (SMR 10)-based pressure-sensitive adhesive were studied. Coumarone-indene resin and toluene were used as the tackifier and solvent respectively throughout the experiment. The results show that viscosity of adhesive increases with addition of sodium sulfate. For rolling ball tack test, the distance traveled by rolling ball decreases with increasing sodium sulfate concentration indicating the increase of tack value with sodium sulfate. The distance traveled by the rolling ball decreases with coating thickness of adhesive. For cross-hatch adhesion test, result shows that maximum adhesion occurs between 30 and 40 parts per hundred parts of rubber (phr) of sodium sulfate content, an observation which is attributed to the maximum of wettability of adhesive. The 60 μm of adhesive coating thickness shows good performance of adhesion property of SMR 10-based pressure-sensitive adhesive.