In oily environments, rubber oil seals perform best when made from materials that resist swelling and maintain elasticity in the presence of hydrocarbons. Among common elastomers, nitrile‑based and fluoro‑based rubbers stand out for this purpose.
Layered Explanation
NBR (Nitrile Rubber): NBR offers balanced resistance to mineral oils and fuels. Its molecular structure limits swelling, allowing the lip to keep its shape under long‑term exposure.
HNBR (Hydrogenated Nitrile Rubber): When higher temperatures or mechanical stress are involved, HNBR provides improved strength and heat stability while retaining oil resistance.
FKM (Fluoroelastomer): FKM handles hot oils, synthetic lubricants, and environments where chemical stability is essential. Its low compression set helps maintain sealing force over extended cycles.
Why Not General Rubber: Standard elastomers absorb oil and lose shape, which leads to leakage. This is why oil‑specific materials are chosen for seals exposed to lubricants.
