Expanded PTFE gasket (also called ePTFE gasket or soft PTFE gasket) is a soft, highly compressible cut gasket made from 100% virgin expanded PTFE sheet. It is twisted, bendable and highly conformable, so it seals steel flanges as well as flanges with irregular or damaged surfaces where a hard gasket would leak. It does not exhibit the cold flow problems of virgin PTFE or the hardness problems of filled PTFE. Kaxite supplies expanded PTFE gaskets cut to size from 1/2" to 24" — and custom gaskets to drawing — in Style 1310 White, with FDA 21 CFR 177.1550 compliance.
Expanded PTFE Gasket is cut from Expanded PTFE gasket sheet, our expanded PTFE gasket sheet made with only pure PTFE resins. It is soft, twistable and bendable, continuing in service to keep its best performance. It has excellent anti-wriggle variation ability and cold current resistance — even in case of cross change of temperature and pressure, good sealing can be assured. It is suitable for use in steel flanges as well as flanges where a highly compressible gasket is required. Expanded PTFE Gasket is also suitable for sealing flanges with irregular surfaces. It will not exhibit the cold flow problems associated with virgin PTFE or the hardness problems of some other filled PTFE products. It has excellent sealability, cuts easily, and separates cleanly from flanges after use.
Expanded PTFE gaskets are specified where the flange is not ideal — where a hard gasket would leak. These are the advantages that make them work:
The table below shows the operating limits and mechanical properties of the KXT 1310 gasket. Use these figures for joint design and for verifying incoming material against the standard.
| Property | Test Standard | Value |
|---|---|---|
| Colour | — | White |
| Density | ASTM D792 | 0.75–0.95 g/cm³ |
| Operating temperature | — | −240 to +260 °C |
| Compressibility | ASTM F36 | 45% |
| Recovery | ASTM F36 | 12–13% |
| Creep relaxation | ASTM F38 | 35–36% |
| Sealability (nitrogen) | ASTM F37B | 0.15 ml/hr |
| Sealability (Fuel A) | ASTM F37B | 0.02 ml/hr |
| Service pressure | — | Full vacuum to 19 MPa |
| Tensile strength (both directions) | ASTM D638 | 16–17 MPa |
| Weather resistance | — | Excellent |
| Chemical resistance | — | Excellent |
Standard expanded PTFE gaskets are cut from sheet in the sizes below. Custom gaskets are produced to drawing — send the outer diameter, inner diameter, thickness, bolt circle and quantity, and we will confirm the achievable tolerance before quoting.
Expanded PTFE gaskets are used as cut gaskets in chemical, food, pharmaceutical and general industrial service — especially where the flange is not ideal or the medium is aggressive.
What is an expanded PTFE gasket?
An expanded PTFE gasket is a soft, highly compressible cut gasket made from 100% virgin expanded PTFE sheet. It is twisted, bendable and highly conformable, so it seals steel flanges as well as flanges with irregular or damaged surfaces where a hard gasket would leak. It does not exhibit the cold flow problems of virgin PTFE or the hardness problems of filled PTFE.
What is the difference between an expanded PTFE gasket and a standard PTFE gasket?
A standard PTFE gasket is cut from dense skived or moulded sheet. It is hard, has very low compressibility, and requires well-machined flanges to seal. An expanded PTFE gasket is cut from expanded PTFE sheet, which is soft and fibrous with 45% compressibility and high recovery. It conforms to irregular flange surfaces, seals at low bolt load and resists creep and cold flow — which is why it is used where a standard PTFE gasket would leak.
What sizes are available?
Standard sizes from 1/2" to 24" are available. Custom gaskets are also produced to drawing — send the outer diameter, inner diameter, thickness, bolt circle and quantity, and we will cut the gasket to your exact requirements. Expanded PTFE gaskets are cut from sheet, so there is practically no upper size limit.
What are the key performance figures of your expanded PTFE gasket?
Colour white. Density 0.75–0.95 g/cm³ (ASTM D792). Operating temperature −240 to +260 °C. Compressibility 45% (ASTM F36). Recovery 12–13% (ASTM F36). Creep relaxation 35–36% (ASTM F38). Sealability 0.15 ml/hr with nitrogen and 0.02 ml/hr with Fuel A (ASTM F37B). Service pressure full vacuum to 19 MPa. Tensile strength 16–17 MPa in both directions (ASTM D638). Weather and chemical resistance excellent.
Is the expanded PTFE gasket FDA compliant?
Yes. Expanded PTFE gaskets from Kaxite are made from 100% virgin expanded PTFE and conform to FDA 21 CFR 177.1550, making them suitable for food, beverage and pharmaceutical processing applications. They also resist nearly all aggressive chemicals.
Where are expanded PTFE gaskets used?
Typical applications include hand-holes and manholes, all types of sealing flange, heat exchangers, compressors and pumps. Expanded PTFE gaskets are used wherever the flange surface is irregular or damaged, or wherever the flange cannot take a high bolt load — glass-lined vessels, plastic flanges, older equipment, and process lines that see cross changes of temperature and pressure.
Page reviewed and updated by the Kaxite technical team · Rev. 2026-01 · Ningbo Kaxite Sealing Materials Co., Ltd, No. 432, Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang, China.
