Teflon is an inert substance and can withstand heavy chemical flow where other materials cannot, providing a safe, highly resilient coating and preventing chemicals from leaking and contaminating anything.
Teflon gaskets are commonly used in the medical and food industries, where hygienic sealing is crucial. Though they cannot withstand high pressures or temperatures – they can only handle up to around 500° F – they can handle cold flow, even cryogenic temperatures, and are frequently used in valve seal applications in the piping and industrial manufacturing industries.
Additionally, they can be used as an alternative to elastomers in o-rings because of their ability to expand or conform to different environments. Iron and steel can be used as alternatives to Teflon, and are commonly used in other types of gaskets, such as metal jacketed gaskets.
However, Teflon has advantages that metals do not; mainly, it has the lowest friction coefficient out of any existing solid. This allows the gasket to be highly chemical-resistant, makes for a better, longer-adhering sealant and provides better flow between machine parts.
Teflon is manufactured by going through the polymerization process. A polymer is a chemical reaction that forms a compound, which then mixes particles with clusters of repeating large molecules to form a substance. Teflon is the polymerized version of tetrafluoroethylene (TFE).
There are three main types of Teflon gasket materials: virgin Teflon, filled Teflon and expanded Teflon. Virgin Teflon is the most generally used since it is just pure Teflon with no fillers. Filled Teflon is virgin Teflon that has a filler added to it during the manufacturing process.
The fillers are typically glass, graphite, carbon or bronze, and each filler has different benefits. Glass acts as a higher wear-resistant and chemical-resistant sealant. Graphite provides less friction, is wear-resistant and also is a strong compressive material.
Carbon fillers do not deform or break down easily and are resistant to various temperatures. Bronze is also a strong compressive material, is wear-resistant and provides good thermal resistance. Expanded Teflon is virgin Teflon that has had a stress resistance added to it during the manufacturing process. This means that the molecular makeup of the material will never settle, which allows the Teflon to continually expand and contract to conform to its environment.
Since no additives are used during this process, expanded Teflon retains the same chemical resistance as virgin Teflon, making it a highly practical and effective gasket material.
Teflon is ideal for gasket use because it is a flexible material that can be die-cut into various shapes and sizes.