Kalrez® Compression Set Resistance and Sealing Force Retention

Kalrez® perfluoroelastomer parts last longer and seal more effectively than other elastomers due to their exceptional heat resistance. Longer-lasting seals can be a direct route to extended mean time between replacement and lower cost of ownership.

Compression set most often causes issues in applications that undergo broad thermal cycling. When a perfluoroelastomer seal is used continuously at high temperatures, it will eventually assume an equilibrium position (shape) as it seals. When the temperature is reduced, the seal may “remember” its equilibrium position.

As the physical volume of the seal gets smaller (thermal contraction), combined with the established equilibrium position, leakage may occur. Should this occur, the seal should be allowed to recover, dimensionally, by raising its temperature before applying fluid pressure to it. This will allow the seal to recover and once again provide the necessary sealing force. Or the seal may need to be replaced.

Unlike some other elastomers, somewhat higher compression set values for perfluoroelastomers are primarily caused by stress relaxation, as opposed to thermal or chemical degradation. Hence, Kalrez® orings remain soft even after long term exposure to high temperatures. Newer grades of Kalrez® perfluoroelastomer parts have low compression set values and offer better resistance to temperature cycling.

This video will discuss compression set resistance and sealing force retention of Kalrez® perfluoroelastomers.

The full agenda can be seen below.