ADHESION PROPERTIES OF STYRENE-BUTADIENE RUBBER-BASED ADHESIVE CROSSLINKED BY BENZOYL PEROXIDE

Adhesion properties of benzoyl peroxide crosslinked styrene-butadiene rubber (SBR)-based pressure-sensitive adhesive were investigated using coumaroneindene, toluene and polyethylene terephthalate (PET) film as the tackifier, solvent and coating substrate respectively. The dosage of benzoyl peroxide ranged from 0 to 5 parts per hundred parts of rubber (phr). Four coating thicknesses, i.e. 30 μm, 60 μm, 90 μm and 120 μm were used in this study. The modes of peel tests were 90°, 180° and T- peel tests. Loop tack, peel and shear strength were determined by a Lloyd Adhesion Tester operating at 10-60 cm min^-1. Results show that loop tack and peel strength increase with benzoyl peroxide dosage up to 2 phr before decreasing with further addition of benzoyl peroxide. This observation is attributed to the optimum crosslinking of SBR where optimum cohesive and adhesive strength occurs at 2 phr of benzoyl peroxide. Shear strength, however, increases steadily with increasing benzoyl peroxide dosage, an observation which is attributed to the steady increase in cohesive strength. In all cases, the adhesion properties of adhesives increase with testing rate and coating thickness.