PTFE Encapsulated O-ring; Chemical resistance

TEFLON® encapsulation is the key element in M-COR Inc.’s ENCAP-O-SEAL™ line of Teflon® Encapsulated O-rings. Due to their ability to resist almost every liquid, gaseous substance and vapor, the O-rings can be used for numerous applications. So few chemicals attack FEP encapsulated or PFA encapsulated O-rings within normal use temperatures that it is more practical to list the exceptions than list compatible chemicals. Here is a list of encapsulated o-ring types:

– FEP Encapsulated Silicone
– PFA Encapsulated Silicone
– FEP Encapsulated Viton
– PFA Encapsulated Viton
– FEP Encapsulated EPDM
– PFA Encapsulated EPDM

Exceptions

Well, there are a few exceptions: FEP/PFA resins are also not compatible with molten alkali metals, fluorine, and several complex halogen compounds, of which chlorine trifluoride is one example. In addition, some of those chemicals can also be reactive at elevated concentrations just below the recommended service limit temperatures for FEP (204°C/400°F) and PFA (260°C/500°F). 80% NaOH or KOH, metal hydrides such as boranes (e.g. B2H6), aluminum chloride, ammonia (NH3), and some amines (R-NH2) as well as imines (R= NH) can also attack the material at elevated temperatures.

In addition, slow oxidative attack has taken place when 70% nitric acid under pressure was heated to 250°C/480°F. Special testing is required when approaching such extremes of reducing or oxidizing circumstances to assure compatibility and security.

Furthermore, M-COR also offers full technical support and testing services to ensure that you find the right material for your project. This may also include supplying specific chemical compatibility information and providing unique testing when required.

Conclusion

So, all in all, M-COR PTFE encapsulated O-rings can be considered a great option for applications where outstanding chemical resistance is needed. Without a few exceptions, such limitations can be easily understood. With the proper testing, your applications will work at their best. *There are many variations of chemical compatibility tests available. For well-documented experimentally obtained data, I recommend referring to reputable industry sources like Compass Publications’ Chemical Resistance Guide for Plastics or Chemours’ Teflon Fluoropolymer Resins Chemical Resistance Guide.* In addition, discussing this with M-COR’s technical support can provide more detailed guidance that aligns with what you need.

By understanding these factors, you will be able to make educated decisions if Teflon® encapsulated O-rings would be best for your applications while continuing to ensure efficiency and safety. Accordingly, for more information or to discuss your specific requirements, please contact M-COR technical support.

CHEMICAL RESISTANCE