PTFE O-Rings | Chemically Inert, Low-Friction Seals

What is a PTFE O-ring?

PTFE (polytetrafluoroethylene) O-rings are highly inert, low-friction seals for aggressive chemistry, clean environments, and low-friction dynamics. PTFE encapsulated O-rings with elastomer cores boost elasticity while retaining chemical resistance.

Composition & Properties

If you need both elasticity and chemical resistance, choose FFKM; for low friction plus elasticity, use PTFE encapsulated cores (e.g., silicone/FKM).

• Low elasticity: pure PTFE lacks rubber elasticity; relies on compression/groove design.
• Low friction: very low coefficient of friction—great for sliding/dynamic seals.
• Chemical inertness: stable against most chemicals/solvents with high cleanliness.

Temperature Range

• Continuous: roughly -200°C to +260°C, depending on formulation/backing.
• Low temp: remains chemically stable but stiffer—ensure adequate compression or use encapsulated cores.
• High temp: near upper limit monitor cold flow/compression set.

Chemical Compatibility

• Suitable: nearly all common chemicals/solvents; corrosive media; clean/food/medical/semiconductor settings.
• Exceptions: molten alkali metals, some high-energy fluorinated chemicals—verify.
• Encapsulated: PTFE outer with various cores (silicone/FKM) to add rebound.

Advantages

• Chemical inertness: handles nearly any medium; clean with minimal extractables.
• Low friction: ideal for dynamic sliding and anti-stick applications.
• Wide temperature: from very low to high heat (-200°C to +260°C).
• Encapsulation option: combines PTFE inertness with elastomeric cores.

Applications

• Chemical/pharma/food: corrosive and clean media where rubber extractables are a concern.
• Semiconductor/vacuum: low particle, chemically inert for vacuum and process lines.
• Dynamic low-friction: valve stems, sliding seals needing low friction and chemical stability.
• Encapsulated rings: add elasticity to PTFE for broader sealing conditions.

Size Coverage (AS568 / Metric)

• AS568, metric, large/custom sizes available; pure PTFE or encapsulated options.
• Compression/extrusion/surface finish guidance based on media/temp/dynamic needs.
• Batch labeling/color coding for cores if encapsulated.

Ordering & Traceability

• Confirm media and temperature to choose pure PTFE vs encapsulated; plan critical orders early.
• Mixed MOQ 1; batch photos/barcodes for traceability.
• If more elasticity is needed, select encapsulated cores (silicone/FKM/FFKM).

FAQs

• PTFE vs FFKM: PTFE is more inert but not elastic; FFKM is elastic with high chemical/heat resistance.
• Low-temp sealing? Needs higher compression or encapsulated core to maintain rebound.
• Dynamic use? Leverage low friction; control gaps to reduce cold flow/extrusion.
• Food/clean? PTFE is inherently clean—suitable for food/medical/semiconductor with proper grades.

Installation & Selection Tips

• Compression: higher than rubber to offset low elasticity; add backup rings for high pressure.
• Surface: smooth grooves/chamfers (Ra 0.8–1.6 μm) to prevent damage and leakage paths.
• Storage: clean/dry, avoid scratches; encapsulated cores follow core storage needs.