PTFE sealing ring

PTFE sealing ring (commonly known as Teflon/PTFE sealing ring) is a performance stable sealing element made of polytetrafluoroethylene (PTFE) as raw material. Its core advantages include good corrosion resistance (based on actual reports), wide temperature range, and relatively low friction, and it is often used in extreme working conditions.

1、 Core performance characteristics

Effective and resistant to chemical corrosion (chemically inert)

Resistant to strong acids, strong bases, strong oxidants, and organic (based on actual reports) solvents (such as aqua regia, hydrofluoric acid, concentrated sulfuric acid), only reacts with molten alkali metals and liquid fluorine.

Wide working temperature

-200 ℃~+260 ℃ (long-term), up to 300 ℃ in the short term. Deep cooling does not cause brittleness, high temperature does not soften, and the cold and hot cycle is stable.

Relatively low friction& self-lubricating

The friction coefficient is 0.04~0.1 (lower in solid materials), and the dry friction is smooth, suitable for oil-free working conditions, and the wear is small.

Non adhesive& Easy to clean

Low surface energy, non stick material, anti scaling, suitable for food/pharmaceutical/semiconductor clean scenes.

Aging and aging; long lifespan

Strong resistance to ozone, UV, and weather, with a theoretical lifespan and excellent after-sales service.

Good insulation

High insulation, low dielectric constant, suitable for electronic and electrical sealing.

main drawback

Poor elasticity and creep (cold flow): prone to deformation under pressure/long-term load, pure PTFE is not suitable for high-pressure dynamic sealing.

Good hardness, average toughness: easy to crack during installation, high requirements for sealing surface smoothness/accuracy.

The price is higher than ordinary rubber.

2、 Commonly used modified (filled) PTFE

Pure PTFE has limited performance, and is commonly used in industry for filling modification to improve strength, creep resistance, and wear resistance (based on actual reports):

Fiberglass filling: improves hardness, wear resistance (based on actual reports), and creep resistance (commonly used).

Carbon fiber filling: relatively low friction, high thermal conductivity, and good dimensional stability.

Graphite/molybdenum disulfide: enhances self-lubricating and dry friction performance.

Bronze powder: enhances thermal conductivity, creep resistance, and load-bearing capacity.

Polystyrene (Ekonol)/PPS: Good performance, low wear, suitable for high speed.

3、 Common types and structures

static seal

PTFE O-ring: stable performance, temperature resistance, but easy to extrude, high pressure requires a backup ring.

Flange gasket/flat gasket: chemical pipelines, valves, reaction vessels.

Dynamic sealing (rotation/reciprocating)

PTFE lip seal (rotary shaft seal): low friction, medium resistant for pumps, gearboxes, high-speed shafts.

V-Ring Packing: High pressure reciprocating (hydraulic cylinder, plunger pump), multi ring stacking, self sealing.

Pan plug seal (spring energy storage sealing ring): PTFE lip+stainless steel spring, ultra-low temperature, high pressure, low speed, strong corrosion (aerospace, semiconductor, chemical valves).

4、 Typical application industries

Chemical/Petroleum: Highly corrosive pipelines, valves, reactors, pumps, filters.

Food/Medicine: FDA certified, sterile, non precipitating, easy to clean, and resistant to CIP/SIP cleaning.

Semiconductors: high-purity gases/chemicals, ultra clean, and free from metal ion pollution.

Aerospace: engines, hydraulic systems, fuel systems, low-temperature (liquid nitrogen/liquid oxygen).

Automobile: engine, gearbox, fuel system, air conditioning, braking system (oil resistant, high temperature resistant (based on actual reports)).

Hydraulic and pneumatic: low friction, long service life, oil-free lubrication conditions.

Electronic and electrical: insulation sealing, weather resistance, chemical resistance.