Contact seals for fluid technology are predominantly manufactured from polymer materials in the group "elastic materials".
The most important characteristics of these materials are their elasticity (adaptation to unevenness and to changing pressure), hardness (wear behaviour), resistance in the pressure fluid (swelling behaviour), sliding and friction behaviour, wear resistance among others.
The elastic materials for seals comprise three groups: the elastomers as the main group, the thermoplastic elastomers and the thermoplastics for special tasks.
Metal materials have become significantly less important for seals in fluid technology. Occasionally there are piston rings and sealing rings made of soft metals that must be deformed to provide sealing.
The correct material defines more than the shape of a seal the functional suitability, operating safety and service life of the seal.