PTFE Ring

Kaxite Sealing's PTFE Ring is a precision-machined virgin PTFE sealing element available in three configurations: PTFE O-rings for static face and radial sealing (or as back-up rings behind elastomer O-rings), PTFE piston rings for dynamic reciprocating and rotary sealing in compressors, hydraulic cylinders and pumps, and PTFE back-up rings for anti-extrusion service at high pressure. Cross-sections 1.5-20 mm, inner diameters 3-600 mm, tolerances to DIN 3771 and AS568. Service range -200°C to +260°C, static pressure up to 80 bar (400 bar with back-up ring), chemical resistance pH 0-14. Available in virgin, modified (TFM), 15-25% glass-filled, bronze-filled and carbon-graphite filled grades. FDA, RoHS, REACH certified. USP Class VI on request. Free samples, 7-15 day lead time.

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Product Description

O-Ring · Piston Ring · Back-up Ring

PTFE Ring — Precision-Machined for Static and Dynamic Sealing

Kaxite PTFE rings are machined or molded from virgin or filled PTFE into circular sealing elements for static and dynamic applications. Three configurations are available: PTFE O-rings for face and radial static sealing (or as back-up rings behind elastomer O-rings), PTFE piston rings for reciprocating and rotary dynamic sealing, and PTFE back-up rings that prevent elastomer O-rings from extruding at high pressure.

Manufactured in Ningbo, China by Kaxite Sealing. Available in virgin, modified (TFM), 15-25% glass-filled, bronze-filled and carbon-graphite filled grades. OEM/ODM custom sizes, bulk wholesale and free samples for qualified buyers.

1.5 – 20mmCross-Section

3 – 600mmInner Diameter

-200 ~ +260°CTemperature

Ra ≤ 0.4μmSurface Finish

Three Ring Types. One Material. Static · Dynamic · Anti-Extrusion

Which PTFE ring do you need?

STATIC · BACK-UP

PTFE O-Ring

Circular cross-section. Seals static faces, flange grooves, valve seats and threaded connections. Frequently used as a back-up ring behind an elastomer O-ring at high pressure.

Round cross-section Static pressure 80 bar AS568 / metric

DYNAMIC · RECIPROCATING

PTFE Piston Ring

Rectangular or step-cut ring. Seals against reciprocating or rotary motion in air compressors, hydraulic cylinders, pumps and valves. Cut so it installs without dismantling the machine.

Butt / Step / Scarf cut Dynamic 30 bar Wear resistant

HIGH PRESSURE · ANTI-EXTRUSION

PTFE Back-up Ring

Flat or concave ring placed on the low-pressure side of an elastomer O-ring. Prevents the O-ring from extruding into the clearance gap at high pressure — raises the working limit from 80 bar to 400 bar.

Flat / Concave Up to 400 bar Extends O-ring life

Material selection guide

GradeProperties

Best forApplication

FDAWearChem.

Virgin PTFEHighest purity

Food, pharmaceutical, semiconductor contact
Universal chemical resistance
Static O-rings and back-up rings

YESLowBest

Modified PTFE (TFM)Low creep

Dynamic seals under thermal cycling
Piston rings in compressors
Better creep resistance than virgin

YESMedBest

15-25% Glass FilledHard / wear resistant

High-load piston rings
Wear-resistant dynamic seals
Compressors and hydraulic cylinders

NoHighGood

Bronze FilledThermal conductivity

High-speed rotating seals
Applications requiring heat dissipation
Dimensional stability under load

NoHighGood

Carbon-Graphite FilledLow friction

Non-lubricated compressors
High-speed dynamic seals
Best combination of wear and friction

NoBestGood

Typical applications

Air compressors

Piston rings on non-lubricated compressors where oil contamination must be avoided. Carbon-graphite or modified PTFE grades.

Hydraulic cylinders

Piston and rod seals, often combined with back-up rings to prevent elastomer extrusion at high pressure.

Chemical pumps

Shaft seals and casing seals where chemical resistance across pH 0-14 is critical. Virgin PTFE preferred.

Valves & actuators

Seat and stem seals in ball, butterfly and gate valves. Back-up rings extend cycle life.

Food & pharmaceutical

FDA-compliant virgin PTFE rings for pumps, mixers and sterile equipment requiring non-leaching seals.

Semiconductor & high-purity

Ultra-clean seals for gas handling, wafer processing and analytical instruments.

Technical specifications

Material options: Virgin / Modified / Filled PTFE
Fillers available: Glass / Bronze / Carbon-Graphite
Cross-section range: 1.5 – 20 mm
Inner diameter range: 3 – 600 mm
Tolerance standards: DIN 3771 / AS568 / Metric
Cut styles (piston): Butt / Step / Scarf / Angled
Service temperature: -200 ~ +260°C
Filled grades temp: up to +290°C
Static pressure: up to 80 bar
With back-up ring: up to 400 bar
Dynamic pressure: up to 30 bar reciprocating
Surface finish: Ra ≤ 0.4 μm
Hardness: Shore D 55 – 65
Chemical resistance: pH 0 – 14
Colour: Natural white / Filled colours
Certifications: FDA / RoHS / REACH

How to order

1. Ring type: O-Ring / Piston / Back-up
2. Inner diameter: In mm or inch
3. Cross-section: 1.5 – 20 mm
4. Height / width: For piston and back-up rings
5. Material grade: Virgin / Modified / Filled
6. Cut style: Butt / Step / Scarf / Angled
7. Operating conditions: Temperature, pressure, media, motion
8. Quantity & target date: Plus destination port
9. Documentation: Material cert / SGS / 3rd party
10. Sample request: Free for qualified buyers

Frequently asked questions

Q1What is the difference between a PTFE O-ring and a PTFE piston ring?

A PTFE O-ring is a circular ring with a circular cross-section, used for static sealing (face seals, flange grooves) or as a back-up ring behind an elastomer O-ring. A PTFE piston ring is a rectangular or step-cut ring that fits into a groove on a piston or rod, providing dynamic sealing against reciprocating or rotary motion — found in air compressors, hydraulic cylinders, pumps and valves. Piston rings are usually cut (butt, step or scarf cut) so they can be installed without dismantling the machine.

Q2Why use PTFE instead of rubber or elastomer for O-rings?

PTFE offers three advantages elastomers cannot: (1) chemical resistance across pH 0-14, including solvents, acids and oxidizers that destroy rubber; (2) service temperature from -200°C to +260°C, far wider than NBR, EPDM or Viton; (3) extremely low friction coefficient and non-stick surface. The trade-off is lower elasticity — PTFE rings do not stretch to seal the way elastomer O-rings do, so they are often used as back-up rings behind elastomers rather than as the primary seal.

Q3Which PTFE grade should I choose — virgin, modified or filled?

Virgin PTFE is the standard grade for chemical resistance and FDA/food contact — the best choice where purity or universal chemical inertness is essential. Modified PTFE (TFM) offers better creep resistance and weldability for dynamic seals. Glass-filled PTFE (15-25% glass) improves compressive strength and wear resistance in piston ring applications. Bronze-filled PTFE offers the best thermal conductivity and dimensional stability under load. Carbon-graphite filled PTFE provides the best combination of wear resistance, low friction and thermal conductivity for high-speed dynamic seals. Send us the operating conditions and we will recommend the appropriate grade.

Q4What is a PTFE back-up ring and why is it used?

A back-up ring (also called an anti-extrusion ring) is a flat PTFE ring placed on the low-pressure side of an elastomer O-ring inside the groove. At high pressure, elastomer O-rings extrude into the clearance gap between piston and bore and fail. The back-up ring fills the gap with a harder, more dimensionally stable material, allowing the O-ring to seal at pressures up to 400 bar instead of the typical 80 bar limit.

Q5Can you make custom-size PTFE rings?

Yes. We machine and mold PTFE rings to any inner diameter, outer diameter, cross-section and tolerance on request. Standard tolerance references are DIN 3771, AS568 and metric. For piston rings we can produce butt-cut, step-cut, scarf-cut and angled-cut designs to match your installation method. Send us a DWG, DXF, PDF or STEP drawing, or specify ID × OD × height plus operating conditions, and we will quote within 24 hours.

Q6What is the MOQ, lead time and sample policy?

MOQ is flexible and depends on ring size, material grade and quantity. Standard lead time is 7-15 days after order confirmation. Free samples are available for qualified buyers — send us the required dimensions, material grade and application, and we will confirm sample lead time. OEM/ODM and private-label packaging are supported.

Request a quotation for PTFE rings

Send ring type, ID × OD × height, material grade and operating conditions — our engineers reply with pricing, lead time and sample availability within 24 hours.

Request a Quote Send Your Drawing

Hot Tags: PTFE Ring, PTFE O Ring, PTFE Piston Ring, PTFE Back-up Ring Manufacturer, Virgin PTFE Ring Supplier, Glass Filled PTFE Ring, Custom PTFE Ring Wholesale

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Contact Info



Address

No 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang China
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Tel

0086-574-87527771
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Email

[email protected]

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