High Pressure Injection Systems

Accurate addition of CO₂ to an extruder is of interest for a number of processes, for example polymer foaming, reactive extrusion and polymer blending. FeyeCon offers custom CO₂ equipment, accompanied with process and product development.

PROCESS
In the case of polymer foams, polymer pellets are fed into the extruder where they melt and are then mixed with CO₂ under pressure. As the material exists through a die, the difference in pressure results in the rapid expansion of the CO₂ saturated polymer to form microcellular foam.

CO₂ also has the ability to act as a plasticizer, thereby reducing the glass transition temperature of polymers. For polymers that exhibit high Tg values, or have a tendency to degrade before melting, the plasticizing effect of CO₂ may assist in the processing of such materials.

EQUIPMENT
FeyeCon operates a lab-scale extruder coupled to a small injection system for the addition of CO₂ in the range of 70-300 bar and 0.1 to 3 kg CO₂/hr. All parameters can be monitored via a data logger.

The design of this injection system provides:

Low pulse addition
Accurate mass flow control
Continuous flow

The flow and pressure range can be specified according to customer request.

APPLICATIONS
This process has been implemented to produce a number of microcellular polymer foams that may be applicable as thermal and sound insulation. Reactive extrusion in the presence of CO₂ also offers a means of improving the processability and the foaming properties of a range of polymer materials.