Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.

Solving Long Time Industry Problem

For several years, one of the biggest drawbacks of “chemically resistant” FFKMs, or perfluoroelastomers, has been their relatively poor compression set resistance. Typically, compounding these materials to be extremely resistant to many different chemical environments comes with the drawback of having to give up their ability to resist taking a set after being under high temperatures for an extended period. Parker's solution to this industry challenge is ULTRA FF156.

Best in class compression set resistance

Compression set refers to a common failure mode of elastomers where a seal permanently flattens out while in application and the joint begins to leak. A material's resistance to this permanent deformation can be easily tested in the lab. To do so, a seal’s thickness is measured, then that seal is compressed about 25% before being heated in an oven at a particular temperature for a predetermined amount of time. That seal is then removed from the oven and the thickness is remeasured.