PTFE O-Ring

Looking for a seal that keeps working where rubber simply cannot survive? Kaxite Sealing manufactures PTFE O-rings from virgin and filled polytetrafluoroethylene for chemical, pharmaceutical, food, semiconductor and high-temperature service. With 15+ years of sealing manufacturing experience, in-house CNC machining and moulding, full material traceability and export to 60+ countries, we help buyers cut leakage risk and maintenance cost — not just supply a part number.

What Is a PTFE O-Ring?

A PTFE O-ring (also called a PTFE sealing ring) is a circular sealing element made from polytetrafluoroethylene, installed in a machined groove between two mating surfaces to stop the leakage of liquids or gases. Because PTFE is almost universally chemically inert and has an extremely low coefficient of friction, it is the material of choice when elastomer O-rings (NBR, EPDM, FKM) would swell, degrade, harden or contaminate the process media.

These seals are typically specified in three configurations:

• Solid PTFE O-ring — used mainly for static sealing (flange faces, covers, closures) where the groove provides the compressive load.
• Spring-energized design — a PTFE jacket with a metal or elastomer energizer inside, used for dynamic and low-pressure static sealing where higher resilience is needed. See our full range of PTFE and PEEK seals.
• Encapsulated / FEP-jacketed O-ring — an elastomer core with a PTFE or FEP outer skin, combining elasticity with chemical resistance.

If your application is a simple, low-cost static seal in oil or water, a rubber O-ring is usually the better economy. If your media is an aggressive acid, solvent, chlorine, steam or high-purity chemical — PTFE is normally the correct answer.

Key Features & Performance Advantages

PTFE Grade Selection Guide

Choosing the right compound is the single most important buying decision. Pure PTFE offers the best chemical resistance but the lowest mechanical strength; filled grades trade a small amount of chemical resistance for much better creep resistance, thermal conductivity and wear performance. We compound these grades in-house — see PTFE modified material for the full filler portfolio.

Technical Specifications

Available Sizes

The table below shows our standard moulded and machined size ranges. Because these rings are frequently machined rather than moulded, we can also produce non-standard and one-off sizes directly from your drawing or sample without tooling cost.

PTFE vs. Rubber O-Rings — Which One Do You Actually Need?

This is the most common question we receive from purchasing teams. The answer depends on three variables: the media, the operating temperature, and whether the seal is static or dynamic.

Groove Design & Installation Guidelines

PTFE does not behave like rubber. Groove dimensions that work for an NBR O-ring will usually leak with PTFE. Below are the practical rules our technical team applies to every enquiry:

• Compression ratio — typically 15%–25% for static PTFE rings, lower than the 25%–30% used for elastomers.
• Groove volume — must be large enough to accept the ring without over-compression, since PTFE has almost no volumetric swell allowance.
• Surface finish — groove and mating surfaces should be machined to Ra 0.4–1.6 µm for reliable sealing.
• Lead-in chamfers — always provide a 15°–30° chamfer to avoid nicking the ring during assembly.
• Thermal cycling — at temperatures above +150°C, allow extra groove clearance for thermal expansion.
• Back-up rings — recommended for pressures above 20 MPa to prevent extrusion.

Send us your groove drawing, media, temperature and pressure — we will confirm the correct section diameter, tolerance and grade at no charge.

Applications

These seals are widely used in equipment exposed to aggressive chemicals, high temperature or strict hygiene requirements:

Quality Assurance & Material Traceability

For B2B buyers, a sealing failure is far more expensive than the part itself. Our quality control process is built around preventing that risk:

1. Incoming raw material control — PTFE resin and compound batches are inspected and recorded before production.
2. Batch traceability — every shipment can be traced back to the raw material batch, machine and operator.
3. In-house machining & moulding — CNC turning, compression moulding and finishing performed in our own facility, not outsourced.
4. Dimensional inspection — inner diameter, section diameter, concentricity and hardness checked against AS568 / DIN 3771 / GB/T 3452.1 tolerances.
5. Pre-shipment sampling — AQL-based random inspection with inspection report supplied with the goods.
6. Third-party testing on request — FDA compliance, USP Class VI, hardness, tensile and compression set reports can be arranged.

We operate an ISO 9001 quality management system and have supplied sealing components to customers in more than 60 countries, including OEM and MRO distributors across Europe, North America, the Middle East and Southeast Asia.

Customization & OEM Service

Kaxite Sealing offers a full custom service to meet your specific sealing requirements:

• Custom inner diameter, section diameter, tolerance and cross-section shape (round, square, rectangular, X-section).
• Virgin, carbon-filled, graphite-filled, glass fiber-filled and bronze-filled PTFE compounds.
• FDA-compliant, USP Class VI and food-contact grades with documentation.
• Custom colors on request — white, black, brown or matched to your sample.
• Laser marking and private-label packaging with your brand and part number.
• Kitting and poly-bagging by size for distributor stock programs.
• MOQ: 100 pcs for standard sizes; lower trial quantities accepted for first orders.
• Lead time: 7–15 days for standard sizes, 15–25 days for custom sizes.

Ordering & Shipping Information

Why Choose Kaxite Sealing

• 15+ years of sealing product manufacturing experience.
• ISO 9001 quality management system.
• Full material traceability from raw PTFE resin to finished part.
• In-house CNC machining and moulding — fast response on custom and one-off sizes.
• Export experience to 60+ countries with proven packaging and documentation.
• Engineering support — groove design review and material selection advice before you buy.
• Fast response within 12 hours on business days.

Explore our full sealing products catalogue, learn more about our factory and capabilities, or contact our sales team directly.

Frequently Asked Questions

What is a PTFE O-ring?

A PTFE O-ring is a circular sealing element made from polytetrafluoroethylene, installed in a groove between two mating surfaces to prevent leakage of liquids or gases. It offers excellent chemical resistance, low friction and a wide operating temperature range from -200°C to +260°C.

What sizes can Kaxite Sealing produce?

Kaxite Sealing produces PTFE O-rings with section diameters from 1.80 mm to 16 mm and nominal inner diameters from 20 mm to 2000 mm. Non-standard sizes can be machined to drawings or samples, normally without tooling charges.

Is it suitable for food and pharmaceutical applications?

Yes. Kaxite Sealing supplies FDA-compliant and USP Class VI virgin PTFE O-rings suitable for food processing, pharmaceutical and medical equipment sealing. Filled grades (carbon, graphite, glass fiber, bronze) are not recommended for these industries.

Can PTFE O-rings be used for dynamic sealing?

A solid PTFE O-ring has limited elastic recovery and is best used for static sealing. For dynamic applications, reciprocating rods or low-pressure gas sealing, we recommend a spring-energized PTFE O-ring, which maintains sealing force as the PTFE wears. Send us the motion type, speed and pressure and we will specify the right solution.

What is the difference between PTFE and rubber O-rings?

PTFE O-rings offer far broader chemical resistance, a wider temperature range (-200°C to +260°C vs. typically -30°C to +200°C for elastomers) and much lower friction. Rubber O-rings offer higher elasticity and better recovery, making them simpler and more economical for standard static and dynamic seals in benign media.

How does Kaxite control quality?

We control raw material batches, keep full batch traceability from resin to finished part, machine and mould in-house, inspect inner diameter, section diameter, concentricity and hardness against AS568 / DIN 3771 / GB/T 3452.1, and carry out AQL-based pre-shipment sampling with an inspection report supplied with the goods.

Do you support OEM and private-label packaging?

Yes. We offer laser marking, custom labels, poly-bagging by size and full private-label packaging with your brand and part numbers. MOQ for private-label packaging starts at 500 pcs per size.