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Teflon is principally used as a gasket material because of it's capability to remain unaffected by the majority of chemicals used in industry. It is also classified, in most cases, as a food grade material, making it acceptable to both medical and food production industries. There are three basic types of Teflon gasket materials. Virgin Teflon, Filled Teflon and Expanded Teflon.
Virgin Teflon is by far the least expensive of the three varieties, and is used in most general applications.
Filled Teflon is a gasket material with a virgin Teflon base to which a substance is added during manufacture to improve the sealing characteristics of Teflon. This "filler" usually is glass or graphite particles although ceramics has sometimes been used. The resulting gasket material is strong, yet highly compressible with very good, though not universal, chemical resistance.
Expanded Teflon is virgin Teflon to which a stress resistance has been added by means of molecular rearrangement during manufacture. This process ensures that the molecular chains from which the Teflon is constructed, do not arrange themselves into set patterns. This means that expanded Teflon possesses no structural weakness (grain) and expands and contracts equally in all directions. Because no additives are required, expanded Teflon also possesses the unique chemical resistance of virgin Teflon. |
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