NBR & FKM

Viton®/ FKM and NBR compounds have several very crucial differences that make them well-suited to certain applications. While both Viton/ FKM and NBR seals act as very good sealing options at moderate temperatures, Viton®/ FKM is far superior for high temperature applications.

Standard Viton®/FKM compounds can provide continuous sealing at temperatures up to approximately +205°C.

Standard NBR on the other hand is only effective for continuous sealing at temperatures up to +110°C (with short term sealing at 130°C.)

At temperatures below -20°C, standard Viton/FKM seals are less effective as they become quite hard and inflexible. Special Viton® / FKM compounds can provide low temperature capabilities of -40°C.

Standard NBR will operate successfully at -35°C (However, some special NBR compounds can provide effective sealing down to temperatures of -55°C,)

In addition to temperature, other application conditions differentiate these two compounds. Viton® /FKM has a wide chemical resistance range, which makes it ideal for most applications involving oils, fuels, and mineral acids. Viton®/FKM also offers excellent resistance to oxidation, ozone, UV exposure, weather, fungus and mould. Although NBR also supports some of the same chemical resistances, it is much less universally resistant than its Viton®/FKM counterpart, suffering degradation from weather and ozone exposure. For most circumstances, however, this may not be an issue. NBR also offers the benefit of superior abrasion and tear resistance making them better suited for more heavy duty industrial applications.