Polytetrafluoroethylene (PTFE)

Polytetrafluoroethylene (PTFE)

Description

Also known as Teflon (Du Pont brand name), PTFE is a highly crystalline thermoplastic with excellent sliding properties, anti-adhesive surfaces, excellent insulation properties, an almost universal chemical resistance and an exceptionally broad temperature deployment spectrum. However, this is offset by low mechanical strength and high specific weight compared to other plastics. To improve the mechanical properties, PTFE is compounded with fillers such as glass fiber, bronze, carbon, graphite etc.

Application

To suit customized applications, the following filled grades are available readily.

  1. 25% carbon filled PTFE
  2. 35% carbon filled PTFE
  3. 40% bronze filled PTFE
  4. 70% bronze filled PTFE
  5. 25% glass filled PTFE
  6. 15% glass filled PTFE
  7. 15% glass + 5% MoS2 filled PTFE

For Every specific requirement, PTFE can be specifically compounded with various fillers to meet your unique requirements.

Applications:

  • Friction bearings,
  • Bearing bushes,
  • Shaft seals,
  • Piston rings,
  • Valve seats / seat rings,
  • Insulators,
  • Flat seals,
  • O rings,
  • Hydraulic seals,
  • Test jacks,
  • Thread guides,
  • Anti- adhesive liners etc,

Main Properties

The main properties of PTFE are:-

    1. Excellent sliding properties
    2. Highest chemical resistance, also to solvents (limited with PTFE+bronze)
    3. .Resistant to hydrolysis (limited with PTFE+bronze)
    4. High corrosion resistance (limited with PTFE+bronze)
    5. Broad temperature deployment spectrum (-200◦C to + 260◦C)
    6. Resistant to weathering
    7. Does not absorb moisture
    8. Physiologically safe (not PTFE+coal/+bronze)
    9. Good electrical insulator (not PTFE+coal/+bronze)
    10. Good thermal insulator (not PTFE+coal/+bronze)
    11. Anti-adhesive
    12. Virtually unwettable with liquids
    13. Fire resistant

Colors: Virgin PTFE (White), PTFE + Bronze (Brown), PTFE + Glass (Off white), PTFE + Carbon (Black), PTFE + Graphite (Dark grey)

PTFE is available sheets, rods and tubes form as well as custom molded part can be manufactured against drawing and specification.

PTFE has excellent sliding properties and because of its very close static and dynamic abrasion values, it prevents the “stick-slip effect”. However, due to its low mechanical strength, PTFE has high sliding abrasion and a tendency to creep (cold flow). Hence unfilled PTFE is only suitable for sliding applications with low mechanical load, its load bearing capacity can be constructively improved by equipping the sliding element with several chambers, it must be ensured that the chambers is fully enclosed so that the slip lining cannot escape (flow out).