Arizona Sealing Devices, Inc. Compound Designation: TF
Standard Color: White
Description: PTFE is a tough, chemically inert polymer possessing an incredible working temperature range.
- Seals for wide chemical exposure situations, with special emphasis on temperature extremes.
- For static and slow intermittent dynamic situations.
Temperature Range: Standard Compound: -300° to +450°F.
Hardness (Shore A): 98
Features: PTFE is inert to virtually all industrial chemicals, even at elevated temperatures. Seals fabricated from this material feature outstanding weather resistance, high resistance to Ozone, and high resistance to the degrading effects of exposure to such solvents as acetone, MEK, and xylene. Possessing average elastomer characteristics of 2,500 to 3,500 psi tensile strength, and 300% elongation, they are tough, impact resistant, low friction, non-twisting performers over an extremely wide temperature range.
Limitations: PTFE is hampered by very poor elastic memory at room, or low temperatures. This presents problems in O-ring installation, requiring extra care to be taken in control over O-ring I.D. stretch. Heating PTFE in boiling water, or in controlled oven, to 200°F is said to enable an O-ring stretch of 10 to 20% to be achieved, thereby assisting installation, and helping to assure tight fit.
Because of its poor tear resistance, during O-ring installation particular care should be taken to avoid nicking or scratching PTFE, as imperfections will cause O-ring leakage.
Finally, the tendency of virgin PTFE to cold flow over time, under gasketing pressures, may require special material compounding (with fillers) to control such “creep” in critical sealing situations.