Expanded PTFE Gasket Material Properties and Common Applications

14 August 2018

Expanded PTFE, also known as ePTFE, is a compressible gasketing material. During production, it’s stretched into sheets, with heat acting as a form expansion facilitator. The process endows the sheets with a tightly organized microstructure, a synthetic fluoropolymer base that’s a lot stronger than it looks. Used as a purpose-designed gasketing solution, the microscopic voids create a soft, irregular surface that suits a broadened number of applications.

Expanded ePTFE: A Transformation Guide 

Before going any further, let’s expand that acronym. PTFE gaskets use Polytetrafluoroethylene as chemically resistant and heat tolerant seals. Elevating the material range, ePTFE physically “expands” the synthetic polymer. During the production phase, the already durable gasketing stuff is exposed to mechanical stretching energy. Fabric-softening heat provides the second structure-transforming ingredient. It’s here that the PTFE transitions, it opens up physically and assumes a web-like structure, which is filled with countless voids.

Loaded with Material Properties 

Solid fluoropolymer nodes stretch into interconnected matrices. The expanded sheets are soft to the touch, and they’re very compressible. That’s a characteristic that any gasketing application can utilize. Moreover, this spongelike form is chemically obdurate, plus it can tolerate 250°C of baking hot heat or -240°C of arctic frost. To make gaskets that can take advantage of those twin properties, the rough and irregularly formed polymer base is layered into laminate strips. Now, with the ePTFE gasket positioned on a pipe flange, thousands of pounds of pressure can be applied. And, with the super-durable base matter capable of resisting the most caustic mediums, the seal won’t fail, not even when a chemical load flows with harsh corrosive impact.

Common Applications for Expanded PTFE 

Conforming to match the most geometrically intricate flange faces, all while displaying a superior strength-to-weight ratio, ePTFE gaskets are mechanically robust, yet they seem deceptively soft. Expect to see this attribute employed specifically in heat exchanger technology. Over at a high-pressure, highly acidic chemical processing plant, the expanded material is working flat-out to endure high pressures while it also packs a chemical-shielding punch. Food processing complexes or solvent-based production plants, the tough fluoropolymer-based gasketing solution will reliably generate a formidable seal.

Expanded PTFE is available as laminated gaskets or as gasket tape. The polymer base does feel deceptively soft and weak, but this sponge-like form conceals a strong matrice-exploded microstructure. Capable of enduring massive quantities of compressive flange-face stress, the seals will quickly conform to the desired seal profile while maintaining the features listed above. Look for glass-lined ePTFE products if even more sealing performance is called for from this synthetic gasketing solution.


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