High Compressive Strength
Compression set is the capacity of elastomers to recover their original thickness after experiencing prolonged compressive and deformation stresses at a given temperature. After a long time under compression, elastomers tend to lose the ability to recover their original thickness. The difference between the original and final dimensions is expressed in percentage and represents the compression set of the material being tested. The lower the compression set percentage the better the material’s compressive strength.
The efficiency of a seal is strongly influenced by the compression set of the material used to make the seal. A low compressive strength, i.e. a high compression set value, can negatively influence the efficiency of the seal, and the sealing function will deteriorate more quickly. A high compressive strength, i.e. a low compression set value, suggests good dynamic and static sealing efficiency over time. As seals are subject to pressure during the working cycle, the ability to recover their original shape at the end of the cycle is essential, in order to prevent fluid leakages.