Continuous Rubber Compounding and Rubber Recycling, Using a Co-Rotating Twin Screw Extruder

Rubber compounding is traditionally performed by means of a discontinuous process. Although based on a well-established technology, it is still a complicated process, not completely automatic, and shows some limits: in particular a high energy consumption, and a difficult quality reproducibility.

Maris Company, which has been manufacturing co-rotating twin-screw extruders since 1962, has developed a continuous process for rubber compounding based on this machine.

Several advantages are introduced by this solution, such as a process simplification, with a higher degree of automation, an easier reproducibility of product’s quality and a reduction of energy consumption.

The continuous process can be performed in two steps or in one step. The former is a more flexible solution, adaptable to a wider range of products. The latter is a more customized one, but it allows a further simplification of the process and a further reduction of production costs.

The benefits introduced by the continuous process, in particular by the one-step solution, from both the economical and environmental points of view, have to be underlined.

Another project that Maris Technological Center is carrying on and that could be of great interest for rubber industry, concerns the development of a process for rubber devulcanization. A completely thermo-mechanical process, based on the co-rotating twin screw extruder, that allows to start from vulcanized rubber (e.g. scraps or post consume, traditionally considered as waste), and to obtain a recycled material with properties similar to crude rubber. This new raw material can be mixed up (up to 50%) with virgin rubber and processed again. The production costs reduction offered by such a solution is evident: less virgin rubber is needed and waste disposal costs are avoided.