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PEEK™ Back-Up Rings


M&P makes custom and standard back-up rings from PEEK™ plastic.


PEEK™ back-up rings are designed to prevent extrusion in elastomer O-ring sealing systems.

Elastomer O-rings serve as effective seals for dynamic and static applications in hydraulic and pneumatic equipment systems. A drawback of elastomer O-rings is their tendency to extrude into the clearance of mating surfaces when subjected to increasing pressures and temperatures. Elevated temperatures impose a severe burden on the physical and mechanical properties of elastomer O-rings, which further increases their tendency to extrude. The combination of high pressures and high temperatures is a common occurrence in present day fluid systems. This establishes the need of the back-up ring in preventing O-Ring extrusion.

M&P makes various types of PEEK™ back-up ring designs.


Virgin PEEK™

  • Engineered thermoplastic.
  • PEEK™ can be used up to 480°F
  • PEEK™ is FDA approved.
  • Excellent chemical resistance.
  • Very low moisture absorption.
  • Good wear and abrasion resistance.
  • The material is BROWN in color.

Glass filled PEEK™

  • PEEK™ with the addition of glass fibers.
  • Glass fibers reduce the expansion rate and increase the flexural modulus.
  • The material is LIGHT BROWN in color.

PEEK™ is a registered trademark of VICTREX.