Teflon was accidentally discovered in 1938 by chemist Dr. Roy J. Plunkett at DuPont's Jackson laboratory in New Jersey, USA: when he tried to make a new CFC refrigerant Tetrafluoroethylene is polymerized in a high-pressure storage container (iron on the inner wall of the container becomes a catalyst for the polymerization reaction). DuPont obtained its patent in 1941 and registered a trademark under the name "Teflon" in 1944. Due to pronunciation in China, the trademark "Teflon" is also called Teflon, Teflon, Teflon, Teflon, Teflon, F4, etc., which are all transliteration of Teflon. Everyone in the industry is used to equating TEFLON, Teflon, Teflon, Teflon, Teflon, Teflon, F4, etc. with PTFE, but in fact TEFLON is just a trademark name of DuPont.
Polytetrafluoroethene, English abbreviated as PTFE, density 2.1 to 2.3 grams per cubic centimeter, flame retardant UL94-V0 grade, dielectric strength greater than 17000V / mm, physiologically inert to biological harm, good aging resistance, PTFE It is a synthetic polymer material that uses fluorine to replace all hydrogen atoms in polyethylene, commonly known as plastic king. It can be processed by molding, turning, extrusion, injection molding, etc., and can be made into PTFE tube, rod, tape, plate, film, etc.
PTFE polytetrafluoroethylene has the following characteristics.
1. Non-stickiness: It has the smallest surface tension in solid materials without sticking any substance. Almost all substances do not adhere to the polytetrafluoroethylene coating film. Very thin films also show good non-sticking performance.
2. High and low temperature resistance: PTFE has excellent high and low temperature resistance, -200 to 260 degrees. It can withstand high temperature to 300 ℃ in a short time, and can be used continuously between 240 ℃ ~ 260 ℃. It has significant thermal stability. It can work at freezing temperature without embrittlement and does not melt at high temperature.
3. Sliding property: PTFE has low friction coefficient and self-lubricating function. The friction coefficient changes when the load slides, but the value is only between 0.05-0.15.
4. Moisture resistance: The surface of Teflon is free from water and oil, and it is not easy to touch the solution during the production operation. If there is a small amount of dirt, it can be removed by simple wiping, saving man-hours and improving work efficiency.
5. Abrasion resistance: Under high load, it has excellent abrasion resistance. Under certain load, it has the dual advantages of wear resistance and non-adhesion.
6. Corrosion resistance: PTFE is hardly attacked by chemicals, and can withstand all strong acids (including aqua regia), strong alkali, except molten alkali metals, fluorinated media, and sodium hydroxide above 300 ° C. The role of strong oxidants and reducing agents. Also resistant to various organic solvents, almost insoluble in all solvents.
7. Polytetrafluoroethylene has poor radiation resistance. It will be degraded after being exposed to high energy radiation, and the electrical and mechanical properties of the polymer will be significantly reduced.
PTFE is widely used in atomic energy, national defense, aerospace, electronics, electrical, chemical, machinery, instrument, instrument, construction, textile, metal surface treatment, pharmaceutical, medical, textile, food, metallurgical smelting and other industries. High and low temperature, corrosion-resistant materials, insulation materials, anti-stick coatings, etc. have become irreplaceable products.
Adding any filler that can withstand the sintering temperature of PTFE, the mechanical properties can be greatly improved, while maintaining other excellent properties of PTFE. Filled varieties include glass fiber, metal, metalized oxide, graphite, molybdenum disulfide, carbon fiber, polyimide, EKONOL, etc., the wear resistance and limit PV value can be increased by 1000 times.
Further reading:
DuPont's Teflon trademark is mainly used on the following products: PTFE, FEP, PFA.
PTFE: PTFE (polytetrafluoroethylene) non-stick coating can be used continuously at 260 ° C, with a maximum use temperature of 290-300 ° C, extremely low friction coefficient, good abrasion resistance and excellent chemical stability.
FEP: FEP (fluorinated ethylene propylene copolymer) non-stick coating melts and flows to form a non-porous film during baking. It has excellent chemical stability and excellent non-stick properties. The maximum operating temperature is 200 ° C.
PFA: PFA (perfluoroalkylate) non-stick coatings, like FEP, melt flow during baking to form a non-porous film. The advantage of PFA is that it has a higher continuous use temperature of 260 ° C and stronger rigidity. It is especially suitable for use in the fields of anti-sticking and chemical resistance under high temperature conditions.