During silicone production, two or more basic components with very different viscosities are mixed together among other processes.

The PRE ensures optimum results here thanks to the special geometry of its mixing chamber and its mode of operation based on the principle of a continuous rolling mill. Depending on the size, up to 48 kneading gaps are possible – this equals approximately 50 individual working cycles on a classic 2- roller mill, which is traditionally used in the silicone sector.

That is what matters: The modular design with effectively separate process zones as well as tight temperature control enables good dwell time control for the reactive linking of large filler volumes.

The mixing in of low bulk density fillers is possible without any problems.

Unique: An internal exchange surface up to 10 times higher than, for example, conventional mixing units like twin-screw extruders, makes the PWE ideally suited for chemical reactions. Reactants can also react well on short process routes. The crucial factor here is the geometry of the system with the rotating planetary spindles.

Fission products and other volatile substances from the reaction can be evacuated efficiently. The PRE can constitute process zones with a vacuum of less than 1 mbar to efficiently degas the extrudate. This is, for instance, how storability is achieved in the first place because no fission products remain that could lead to further reactions. In addition, odors and possible toxic gases are removed, thus making a valuable contribution to quality assurance and increasing occupational safety. This is made possible by a self-contained continuous manufacturing process in the PRE, which replaces the batch process still often used in silicone production.

Depending on the customer's requirements, additives, coloring by liquid injection or solids can be introduced into the process via a gravimetric dosing system with coupled side feeders. “Due to its modularity, the PRE offers very high flexibility and can be adapted to the individual needs of customers and their processes,” Dr. Thomas Birr summarized.

On the whole, compounding silicone with the planetary roller extruder creates the possibility of producing silicones – on an industrial scale with up to several tons per hour – in a continuous process with consistent first-class quality at a very high degree of automation and high occupational safety.

ENTEX is continuously expanding its expertise in the compounding of silicone with the planetary roller extruder and offers an attractive ROI due to the advantages mentioned.