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What is Simriz®? 

Simriz is a family of perfuoroelastomer compounds developed solely by Freudenberg and designed to provide superior chemical resistance and thermal stability. Simriz possesses the resilience of an elastomer with chemical resistance approaching that of PTFE.

Why Simriz®?

There are two types of cure systems typically used in FFKM materials. 

1. Peroxide-which offers good resistance to many chemical, acids and bases, but does not offer 325°C (620°F) high temperature resistance (the cross-link breaks down before the polymer)
                  Examples include: Simriz® Z7257, Parker Parofluor® V8545-75, Chemraz® 618 AMS 7257 materials 

2. Triazine (Nitrile) – offers the best thermal stability to 325°C (620°F), but can be susceptible to chemical attack
                  Examples include: Kalrez® 4079, Kalrez®7075 and Parker Parofluor® Ultra FF200-75 

3. Freudenberg-NOK Simriz® offers a patented Triazine cross-link with polymer structure modifications. This unique cure system offers a broad chemical resistance not offered by other competitive materials.  Simriz® compound 498 is one of the only elastomeric compounds to tolerate 25% squeeze at 315°C (600°F) for long-term operating times.

High Temperature compression set resistance
Compression set, AS568-214 O-Rings, whole O-Ring testing 25% Squeeze, at 315°C (600°F), for 300 hours

      Material % Permanent set Comments Cr plated steel corrosion
      Simriz® 498 40 OK Slight
      Leading competitor 55 OK Severe

This test is particularly difficult for FFKM’s due to the high thermal expansion, which leads to material splitting at 25% compression.
Simriz® 498 performs well due to the proprietary cross-link system, allowing this compound the ability to not rupture at these temperatures.  

Check out the highlighted link to learn more about the different Simriz® FFKM compounds

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