What is pressure resistance?
Pressure resistance describes the ability of a material or component to withstand mechanical pressure without permanently deforming or cracking. In rubber and plastics technology, it is central to Seals, Sealed seats, hoses, spring elements and other functional components that are used under pressure load.
Factors influencing the pressure resistance
- The pressure resistance of a material is influenced by
- Material type and degree of cross-linking
- Component geometry and wall thickness
- Temperature and duration of the load
- Ageing and media contact (oil, vapour, chemicals)
Elastomers such as FKM, HNBR or EPDM show very good compression set resistance even at higher temperatures, depending on the formulation.
Measurement of pressure resistance
- Standardised test methods determine the compression set via:
- Compression set (DIN ISO 815)
- Short-term compression set under defined load
- Tests at elevated temperature to evaluate the long-term behaviour
- Simulation of real installation conditions
Compression set (DVR)
- Is a parameter for the permanent deformation of a sample after a pressure load for a defined time under defined ambient conditions (temperature / media load)
- DVR (%) = (l_0 - l_2) / (l_0 - l_1) x 100
- l_0: Height of the sample before the test
- l_1: Height of the sample during the test under compressive load
- l_2: Height of the sample after the test in the unloaded state
- A DVR of 100% means that there is no deformation after the load, whereas the sample returns to its original height with a DVR of 0%.
The aim is to ensure long-term functionality under pressure, e.g. for flange seals or piston sleeves.