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An Expanded PTFE Sheet is a highly versatile and advanced material made from polytetrafluoroethylene (PTFE) that has been expanded to create a microporous structure. This unique process results in a material that retains the excellent chemical resistance, non-stick properties, and broad temperature tolerance of standard PTFE, while also gaining enhanced mechanical properties like improved tensile strength, flexibility, and compressibility. It is a white, soft, and formable sheet used extensively across various demanding industries for sealing, filtration, and insulation applications.
Our expanded PTFE sheets are engineered to meet precise industrial standards. The following table details the key physical, mechanical, and thermal properties. These values are typical and can be customized based on specific manufacturing processes and densities.
| Property | Standard Value / Range | Test Method / Conditions |
|---|---|---|
| Density | 0.4 - 1.2 g/cm³ | ASTM D792 |
| Tensile Strength (Machine Direction) | 2,000 - 10,000 psi (13.8 - 68.9 MPa) | ASTM D638 |
| Tensile Strength (Transverse Direction) | 1,000 - 5,000 psi (6.9 - 34.5 MPa) | ASTM D638 |
| Elongation at Break | 50% - 400% | ASTM D638 |
| Compressibility | 10% - 60% | ASTM F36 (at 2,000 psi) |
| Recovery | 40% - 85% | ASTM F36 |
| Creep Relaxation | 10% - 40% | ASTM F38 |
| Operating Temperature Range | -450°F to +600°F (-268°C to +315°C) | Continuous Service |
| Thermal Conductivity | 0.10 - 0.25 W/m·K | ASTM C177 |
| Dielectric Strength | 100 - 500 V/mil | ASTM D149 |
| Surface Energy | ~18 dynes/cm | - |
| Water Absorption | <1% | ASTM D570 |
| Flammability | Non-flammable | UL94 V-0 |
We offer expanded PTFE sheets in a variety of standard and custom sizes to fit your specific application requirements.
The primary difference lies in the microstructure. Virgin PTFE is a solid, non-porous polymer. Expanded PTFE is created by a process that stretches the PTFE, creating a strong, microporous matrix of nodes and fibrils. This structure gives expanded PTFE significantly higher tensile strength, greater flexibility, and some degree of breathability while maintaining the chemical and thermal properties of virgin PTFE.
Yes, expanded PTFE sheets exhibit excellent creep resistance and recovery, making them suitable for many high-pressure sealing applications, especially in flanged connections. The specific pressure rating depends on the sheet's density, thickness, and the gasket design. For extreme pressures, it is often used in combination with other sealing elements or in a compressed form. Always consult engineering data for the specific pressure and temperature conditions of your application.
Installation is straightforward. Ensure flanges are clean, aligned, and free of scratches. Place the ePTFE gasket between the flanges. For bolted connections, use a star-pattern tightening sequence. The recommended bolt load is generally lower than for traditional gaskets. A typical starting point is to torque bolts to 50-60% of the yield strength of the bolt material, then perform a final pass to achieve full, even torque. Always refer to the manufacturer's specific torque recommendations for the gasket grade and size.
While PTFE itself has excellent resistance to UV degradation and weathering, the porous nature of expanded PTFE can make it susceptible to contamination from dirt and moisture if used unprotected outdoors. For long-term exterior exposure, it is often recommended to use a coated or laminated version, or to ensure it is housed in a protective enclosure to maintain its performance and appearance.
Absolutely. Expanded PTFE sheet is an outstanding electrical insulator. It possesses a very high dielectric strength and volume resistivity, and it maintains these properties across its entire wide temperature range and in high-humidity environments. It is commonly used to insulate wires, cables, and sensitive electronic components.
Expanded PTFE sheet is soft and formable, making it easy to fabricate. It can be cleanly cut with sharp blades, scissors, or utility knives for simple shapes. For high-volume production or complex profiles, die-cutting, CNC knife-cutting, or laser cutting are highly effective methods. It can also be easily punched or stamped. When cutting, use sharp tools to prevent tearing or fraying of the material.
Many grades of our expanded PTFE sheet are manufactured to be compliant with FDA regulations 21 CFR 177.1550 for repeated use in food contact applications. They are also often certified to USP Class VI standards for medical device use. It is crucial to specify your requirement for FDA or USP compliance when ordering to ensure you receive the correct, certified material.
Expanded PTFE is an extremely stable polymer with an indefinite shelf life when stored properly. It should be kept in a cool, dry place away from direct sunlight, extreme heat, and sources of contamination. There are no plasticizers or additives that can migrate out or cause the material to degrade over time.
