PREDICTION OF CURE TIME FOR A RUBBER CEMENT USED FOR CONVEYOR BELT SPLICING

The evolution of bonding strength for a commercial cold vulcanizing rubber cement was determined using small-scale simulated conveyer belt splicing. Peel and shear data obtained under isothermal conditions fit a modified Avrami model X = 1 - exp(-kt1/2), where X is the degree of ultimate shear or peel bond strength obtained and the rate constant k shows a typical Arrhenius type temperature dependence k = 42 exp(1670/T) min1/2 for peel strength, and k = 57 exp(-2000/T) min1/2 for shear strength. (T is the absolute temperature in K.) Bonding strength evolution under nonisothermal cure conditions can be estimated by integrating the general rate expression dX/dt = 0.5k2(1- X)/(-ln[1 - X]).