Silicone extraction with the Enertia™ branded machine by Cool Clean Technologies successfully extracts volatiles from silicones and other elastomers at room temperature by exposing the component to liquid CO2 under carefully controlled conditions. The liquid CO2 is non-toxic, non-flammable, non-corrosive, odorless, chemically stable, and acquired from recycled sources (does not contribute to global emissions). Liquid CO2, or LCO2, has several characteristics that make it an ideal silicone extraction agent for removing volatiles from elastomers. LCO2 has an affinity for silicones and other volatile components, can easily diffuse into porous elastomeric structures, and has very low surface tension. As a result, when the elastomer is exposed to liquid CO2, it first penetrates then solubilizes un-cured and non-crosslinked compounds, forming a solution which diffuses out of the elastomeric matrix and into the bulk of the chamber. Studies have shown that this process does not materially change most elastomers and has advantages over traditional bakeout and vacuum bakeout alternatives.
The Cool Clean Enertia™ is an automated system that is very easy to use. After the products are inserted into the chamber and the start button is pressed, the system gently introduces liquid CO2. PLC controls the process parameters and exposure time, and has a programmed pressure reduction scheme to safely reduce the pressure. Upon completion, the door is unlocked and the parts are ready for use or the next process. The Enertia™ system is virtually a closed system, recovering 99% of the CO2 used in the process. Using this silicone extraction process has the following advantages.
- Removes volatile compounds to parts-per-million level;
- LCO2 extracted silicone rubber contains less extractables and yields a higher tensile strength than traditional vacuum bakeout processed materials;
- Extraction is performed at room temperature, eliminating potential damage or premature wear from high temperature exposure;
- Safe to use thru ‘post cure’ in combinations with thermoplastic materials;
- The process can avoid slit healing – even after gamma sterilizations;
- 100% environmentally friendly;
- Cycle time of a few hours, versus a few days.
This process is based on the properties and advantages of liquid CO2 as the inert extraction media and represents an alternative to the expensive heat curing method currently used in this industry. In addition, with CO2 extraction no volatiles are rejected to the environment and can be easily captured and recovered.