Abstract

The adhesion properties of epoxidized natural rubber (ENR 25 grade)-based adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loading was from 10 to 40 parts per hundred parts of rubber (phr). The footwear substrates: Microcellular (MC) Resin rubber (RR) and leather (LT) outsoles were used. The lap shear and peel strength were determined by a Llyod Adhesion Tester operating at 8cm/min. The assessment of the bonding strength, such as viscosity, peel strength, lap shear test, and as well as the effect of temperature and chemicals on the adhesive bonds were carried out on the outsoles using standard methods. FTIR result of the ENR compounds showed important characteristics peak confirming the presence of Epoxide group and CaCO3. Results obtained shows that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading from 10-40phr due to the concentration effect of the filler. However, for lap shear and peel strength, it passes through a maximum at 30 phr loading of calcium carbonate, an observation which is attributed to the optimum wettability of adhesives on the substrate. Temperature had a slight effect on the peel and lap shear test. The adhesive showed good resistance to cold and hot water as the filler loading increases from10-40phr filler loading. The microcellular out- soles showed the best adhesion properties in terms of lap shear test and peel strength of the adhesive bonds. This is confirmed from the maximum results of 83.3N/m2 and 458.3N/m2 corresponding to peel and lap shear of the adhesive bonds respectively. The produced adhesive showed an expedient adhesion property which can be applied in footwear production.