Adhesion Properties of Epoxidized Natural Rubber (ENR 50)-based Adhesive in the Presence of Magnesium Oxide

Adhesion properties of epoxidized natural rubber (ENR 50)-based adhesive were studied in the presence of magnesium oxide. Coumarone-indene resin and toluene were used as the tackifier and solvent, respectively. A SHEEN hand coater was used to coat the adhesive on a polyethylene terephthalate substrate at 30, 60, 90, and 120 μm coating thickness. Viscosity was measured by a HAAKE Rotary Viscometer whereas loop tack, peel and shear strength was determined by a Llyod Adhesion Tester operating at 30 cm/ min. Results indicate that viscosity of adhesive increases steadily with magnesium oxide content. Loop tack and peel strength show maximum values at 30 parts per hundred parts of rubber of magnesium oxide where maximum wettability occurs. The 60-μm coated sample consistently exhibits the highest tack and peel strength. Shear strength, however, decreases with increasing magnesium oxide loading for all coating thickness investigated in this study.