For the development of a continuous mixing process on the twin screw extruder it is important to choose the best screw elements. In this work a comparison between the different dispersiv mixing elements is done. The paper shows also the influence of the other parameters on the mixing process like feed rate, screw speed and the pressure build up in the die. The aims pursued here developing a continuous mixing process with powder rubber are to achieve good dispersion of the filler and a low mixing temperature in order to prevent scorching of the rubber compound.