Scorch arisen prediction through elastomer flow in extrusion die

The thermal and kinetic behaviour of an elastomer flow inside an extrusion die is numerically investigated. The aim is to control scorch arisen and reduce the heating time in the mould by using viscous dissipation phenomena in order to improve the rubber compound curing efficiency. A three dimensional model, using the particle tracking technique, is developed in order to get thermal, velocity and kinetic fields through the flow. Three common geometries of an elastomer forming process are modeled: a straight runner, a bend zone and a bifurcation. This simulation is applied on the case of an EPDM (ethylene propylene diene monomer) flow. The thermal and rheological properties are experimentally characterized. The influence of viscous dissipation on the reaction progress of the melt is studied on several process conditions. Many criterions relevant for thermal and cure homogeneity are proposed in order to quantify the performance of geometry modifications.