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Critical Properties - Kalrez® O-Rings and Seals

Because Kalrez seals and o-rings are so resistant to chemicals and so stable at extreme temperatures, they last longer and seal more effectively than parts made from other elastomers. They are cost effective because of the extended time between replacements.

Thermal Stability

Kalrez seals can remain elastic and recover from exposure to long-term high temperatures (up to 327°) better than parts made from other elastomers designed for high temperatures. The main cause of failure in a high temperature application is embrittlement and hardening. Kalrez maintains its integrity far longer than other elastomers.

In high-vacuum applications, Kalrez has almost no outgassing over a wide range of temperatures. This helps reduce pump-down times, an important factor in semiconductor manufacturing and other applications where it is critical to have a contamination-free environment.

Exceptional Chemical Resistance

Kalrez parts have virtually universal chemical resistance. They withstand attack by more than 1,800 chemicals including solvents, amines and plasmas. These parts are superior to and last longer than parts made from other elastomers designed to resist chemicals.

Maintains force retention to keep parts tight

As proven in ISO 334 tests, Kalrez outperforms other elastomers when it comes to sealing force retention, a measure of how long the parts will last. Even under harsh and aggressive conditions, it will retain its sealing force longer in both short and long-term serivces. And thanks to its true-rubber resiliency, it also prevents leaks caused by creep, a major problem with PTFE and other plastic materials.

Low Compression Set


Long-Term O-Ring Compression Set at 204ºC (400ºF)

Kalrez compression set chart


As shown above, Kalrez parts exhibit low compression set, maintaining their elastic recovery which means seals remain tight for a longer time. Since these parts recover better while under compression than other perfluoroelastomers, they also hold their shape better under long-term stress.

DuPont™ and Kalrez® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company or its affiliates. All rights reserved.