the pressure resistance of O-ring materials

In order to improve the pressure resistance of the O-ring material, To increase the elasticity of materials (especially to increase their elasticity at low temperatures and reduce their compression permanent deformation), it is generally necessary to improve the material formula and add plasticizers. However, O-ring seals with plasticizers, which are soaked in the working medium for a long time, will gradually be absorbed by the working medium, leading to volume shrinkage of the O-ring seal and even negative compression of the O-ring seal (i.e., there is a gap between the O-ring and the surface of the sealed part). Therefore, when calculating the compression amount of the O-ring and designing the mold, these shrinkage amounts should be fully considered. The compressed O-ring should be soaked in the working medium for 5-10 days and nights to maintain the necessary size.

The compression permanent deformation rate of O-ring material is related to temperature. When the deformation rate is 40% or greater, leakage occurs, so the heat resistance limits of several rubber materials are: nitrile rubber 70 ℃, EPDM rubber 100 ℃, and fluorine rubber 140 ℃. Therefore, various countries have regulations on the permanent deformation of O-ring seals.