Experimental Determination of Shear‐Thinning Behaviour During Extrusion of Rubber Blends

Abstract: In this contribution, the influence of an extrusion process on the viscosity function of rubber blends is identified. This knowledge is required for realistic numerical simulations of injection heads and extrusion tools used for the fabrication of rubber profiles. The experimental basis of this investigation is tests with both, capillary and extrusion rheometer. The latter is a combination of an industrial extruder and an extrusion tool with a circular cross‐section, allowing application of material characterisation methods used for capillary experiments. Thus, the determination of the viscosity function of extruded rubber blends is possible. Additional capillary experiments enable the determination of the influence of an extrusion on the viscosity of rubber blends. For the identification of material parameters, a non‐linear iteration scheme is used, which is proven to be applicable for rubber compounds and rubber blends. The validation of the extrusion rheometer tests is performed by means of numerical back‐calculation of the corresponding pressure measurements.