What Are Kalrez O‑Rings? The Ultimate High‑Performance Seal

Author : 孟 笑 | Published On : 28 Mar 2026

When standard elastomers fail under extreme heat or aggressive chemicals, engineers turn to Kalrez O‑rings. Manufactured by DuPont, Kalrez is a perfluoroelastomer (FFKM) that combines the flexibility of rubber with the chemical resistance of PTFE (Teflon). This unique property makes it the material of choice for the most demanding sealing applications across semiconductor, chemical processing, aerospace, and pharmaceutical industries.

A Kalrez O‑ring maintains its sealing force in environments where traditional fluoroelastomers (like FKM/Viton) quickly degrade. With continuous service temperatures ranging from -20°C up to 327°C (depending on the grade), and near-universal chemical compatibility—including resistance to plasma, aggressive acids, amines, and solvents—Kalrez seals ensure reliability where downtime is not an option.

DuPont offers various Kalrez grades tailored to specific applications. For example, Kalrez 6375 is widely used in semiconductor etch processes for its exceptional plasma resistance, while Kalrez 4079 is formulated for chemical processing and oil & gas environments requiring superior resistance to amines and sour gases.

Selecting the right FFKM O‑ring involves more than just size. Factors such as temperature extremes, media exposure, and required compression set must be considered. When properly specified, a Kalrez O‑ring can last months or even years in applications where other seals would fail in days, ultimately reducing maintenance costs and increasing system uptime.