Materials used for O-rings include nitrile rubber, carboxynitrile rubber, fluororubber, ethylene propylene rubber, hydrogenated nitrile rubber, silicone rubber, chloroprene rubber, fluorosilicone rubber, polyurethane, chlorohydrin rubber, styrene-butadiene rubber, butyl rubber, natural rubber, ethylene/ethylene propylene rubber, polyacrylate rubber, perfluorinated rubber, etc.
The performance indicators of the same type of rubber can vary significantly depending on the formulation. Therefore, simply listing nitrile rubber or nitrile-40 in the material column is inaccurate. The Ministry of Chemical Industry has specific standards for materials used in O-rings, such as: HG/T 2579-1994, HG/T 2021-1991, HG/T 2333-1992, HG/T 3089-2001, HB 5290-1991, etc. HG/T 2579-1994 specifically removes the specific material category, only providing some performance indicators.