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Low Friction PTFE O-Rings

black PTFE o-rings

Polytetrafluoroethylene (PTFE for short) is a low friction synthetic rubber that has long been used for sealant applications for a variety of substances including gasses, fluids, and chemicals.

PTFE O-Ring Temperature Range

Although PTFE has lower mechanical properties compared to other plastics, the material’s chemical resistance in tandem with its ability to withstand a wide temperature range (-100oF to +400oF) allow PTFE o-rings to provide effective resistance to weathering as well as electrical and thermal insulation.

Because PTFE is such a dense material, it cannot be “melt processed” – it must be compressed and sintered to form useful shapes (like o-rings).

   Top Applications

   Mechanical Weaknesses

    • outdoors
    • lubricants
    • hydrocarbons
    • acids
    • alkalis
    • detergents
    • alcohol
    • ketones
    • steam
    • refrigerants

    • high vacuum seals
    • low compression vacuum sealing flanges
    • super-heated steam

Increase Mechanical Properties with Filled Grades

As shown in the table above, PTFE o-rings have some mechanical vulnerabilities compared to other plastics. If needed, these properties can be enhanced by adding fillers, such as:

      • Glass Fibers
      • Carbon
      • Graphite
      • Molybdenum disulphide
      • Bronze

“Filled” o-rings maintain their excellent chemical and temperature resistance while fillers improve mechanical strength, stability, and wear resistance.

FillerPhysical FormAmount (% Weight)Effect of Filler
Glass Fibers Milled Fibers Up to 40% (also in combination with - graphite, MoS2, and carbon)
  • increased wear resistance
  • increased compressive strength
  • reduced cold flow
  • resistant to organic solvent
  • increased rigidity
Carbon Powder Up to 35% (also in combination with graphite, bronze, and glass)
  • increased compressive strength
Carbon Fibers Milled Fibers Up to 30%
  • increased hardness
  • increased wear resistance
  • improved thermal conductivity
  • good dry running properties
  • electrically conductive at higher filler contents
  • resistant to hydrofluoric acid
Graphite Powder Up to 25% (also in combination with glass, bronze, and carbon)
  • Improved sliding properties
  • Reduced coefficient of friction
  • Improved thermal conductivity
Bronze Powder Up to 60% (also in combination with carbon, graphite, and MoS2)
  • Increased compressive strength
  • Increased hardness
  • Increased wear resistance
  • Improved thermal conductivity
  • Reduced cold flow
Molybdenum Disulfide (MoS2) Powder Up to 5% (also in combination with glass and bronze)
  • Improved sliding properties
  • Increased wear resistance
Stainless Steel Powder Up to 60%
  • Improved thermal conductivity
  • Reduced cold flow
  • Resistant to most chemicals
Polymers Powder Up to 20% (also in combination with inorganic fillers)
  • Increased wear resistance
  • Not abrasive to mating surface
  • For soft mating surfaces
Pigments Powder Up to 2%
  • For coloring (identification)