PTFE GASKET
PTFE is renowned for its exceptional chemical stability, remaining almost chemically inert in the face of most aggressive media. This makes it an invaluable gasket material for extreme chemical applications.
However, pure PTFE’s tendency to creep under load has historically limited its use in high-compressive-load environments.
To overcome this challenge, Modified PTFE materials are utilized. Modifications—such as expanding the PTFE (for higher strength) or adding inert fillers (like silica, silicon carbide, or barium sulphate)—dramatically improve the material’s hot and cold flow resistance, thereby enabling its use at higher compressive loads and temperatures without sacrificing its superior chemical resistance.
1. General Properties
- Outstanding chemical resistance
- Suitable for foodstuffs & pharmaceuticals
- Insoluble in solvents (even at high temperatures)
- Excellent electrical insulating capacity
- Stable to light & does not absorb water
- Low thermal conductivity
2. Expanded PTFE (ePTFE)
Expanded PTFE boasts good creep resistance and superior bolt torque retention. This modification produces a softer material with higher strength, allowing it to seal higher internal pressures and operate at elevated temperatures.
3. ePTFE Key Attributes
- Good mechanical properties (low to medium temperatures)
- Excellent chemical resistance
- Highly compressible
- Available in sheet, cut gasket, or adhesive tape roll form
4. PTFE Envelope Gaskets
This design uses a PTFE envelope to protect an inner compressed synthetic fibre gasket insert from chemical attack. This approach is highly effective because it:
- Provides excellent chemical resistance (from the PTFE)
- Offers the strength and resilience needed for joint stability (from the fibre insert)
- Reduces the negative effect of PTFE’s poor stress retention.
- Offers chemical resistance under moderate conditions of temperature and pressure.