Effect of Mixing Process on Mooney Viscosity and Die Swell Behavior of Rubber Compound

The effects of rubber mixing conditions, such as the changes in material loading procedure and rotor speed on die swell behavior were studied with the aid of an experimental small extruder. Also the changes were examined on Mooney viscosity of the compounds, simultaneously. It is shown that these changes in mixing condition considerably affect the Mooney viscosity of the compounds rather than die swell. Two control parameters of Mooney viscosity and die swell, i.e. "rubber breakdown" and "filler dispersion in mixing process" were identified and it may be concluded that the role of thesecond agent on die swell behavior is not very significant. Finally, by feeding the final compounds in an industrial extruder, it is observed that these processing variables on die swell and extrusion behavior of compound play little effect compared to the formulation variables. The experimental die swell parameter, however could predict the extrusion behavior much better than Mooney viscosity parameter.