Abstract: An elastomer masterbatch or a compounded productive elastomer stock is made using a twin screw extruder to mix elastomer components in multiple mixing zones at controlled temperatures. Elastomer and other ingredients are fed into the twin screw extruder continuously through precise loss-in-weight or volumetric feeders. The degradation temperature and/or cross linking temperature of the elastomer determines the rate at which the elastomer can be processed, since friction created during mixing heats the elastomer. Accordingly, the maximum rate of compounding is a function of the torque limit, cooling efficiency, and conveying capacity of the extruder. The conveying capacity and torque limit are also a function of the size of the extruder. The viscosity of the elastomer compound in the extruder, as measured by a Mooney viscosimeter (ASTM D1646), is typically in the range of about 20 to 250 units (ML(1+4)100C).