Polytetrafluoroethylene (PTFE), also known as teflon/teflon or plastic king, is a copolymer of tetrafluoroethylene monomer. First, it was developed for national defense and cutting-edge technology and development but later it has gradually extended to civil use, which is generally applied to corrosion-resistant pipes, containers, pumps, high frequency communication equipment and wireless electrical equipment with high performance requirements.
PTFE seal has become the common seal material for its unique properties.
Stability: almost all chemical resistance, strong acid, strong alkali or strong oxidizer and organic solvents have no effect on it.
Thermal stability: pyrolysis temperature above 400 ℃, therefore, it can work within the scope o - 200 ℃ ~ + 350 ℃.
Wear resistance: the friction coefficient of PTFE material is extremely low, only 0.02, which is 1/40 of rubber.
Self-lubricating: the surface of the PTFE material has a prominent self-lubricating property, and almost all of the viscous material cannot adhere to its surface.
However, the pure PTFE has the low strength and the abrasion performance is not very perfect. Usually some inorganic particles are put into the polymer PTFE, such as graphite, molybdenum disulfide, molybdenum disulfide, aluminium oxide, glass fiber, carbon fiber and so on to improve its mechanical properties. It also can be used with other polymers, such as polystyrene resin (PHB), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), poly (perfluorinated (ethylene/propylene copolymer (PFEP) blending method to extend its damping temperature range and improve the creep resistance. Therefore, different mechanical seal materials produce all knids of PTFE mechanical seals.
properties | unit | pure PTFE | glass fibire filled PTFE | carbon filled PTFE |
density | g/cm3 | 2.2 | 2.3 | 2.08 |
tensile strength | MPa | 30 | 15 | 13 |
max. working temperature | ℃ | 260 | 260 | 260 |