Patent ID: 7452940

Claim:
Process for the preparation of a dynamically vulcanized thermoplastic elastomer comprising melting and mixing a thermoplastic polyolefin, a vulcanizable rubber and a curing agent in a co-rotating twin-screw extruder, whereby the vulcanizable rubber is cured during mixing, wherein tr<40 sec, Espec/tr>=24 kW/kg, tr/(L/D)<0.60 sec, and the rotation speed of each co-rotating twin screw in the extruder varies from 500 to 1200 rpm; and whereby tr means the total residence time in the extruder, Espec means specific Energy (kWh/kg) in the extruder and represents mechanical energy in kWh supplied by an extruder motor to the thermoplastic elastomer per kg, and (L/D) means Length/Diameter ratio of the screws in the extruder.