Teflon (PTFE) is often fabricated into fasteners, such as screws, hex nuts, hex head cap screws, flat washers, and others. It is also used to fabricate custom parts. However, this material can only be turned, or made into parts on a CNC machine. It can also be compression molded though is unable to be injection-molded. This is because it’s not a thermoplastic.
Teflon or PTFE was discovered in 1938. (Image: Craftech Industries, Inc.)
PTFE is a solid fluorocarbon and synthetic fluoropolmer. In other words, this material is wholly made of carbon and fluorine atoms. It has a high molecular weight and is hydrophobic, meaning it does not absorb water.
Fasteners and custom parts with PTFE are used in applications where high heat and chemical resistance are required. One disadvantage is that PTFE is that it’s not very strong. For instance, it is so soft you can make an imprint in the material with a fingernail.
Discovering Teflon
Teflon (PTFE) or polytetrafluoroethylene was accidentally discovered in 1938. A DuPont chemist named Roy J. Plunket was attempting to produce chlorofluoroethylene, a refrigerant. Instead he made another discovery: the inside of one bottle was coated with a waxy and very slippery material.
Teflon became a registered trademark in 1945. By 1948, a DuPont company, Kinetic Chemicals, partnered with General Motors. They produced over 900 tons of Teflon per year. One of the early uses of the material was in the Manhattan Project. It was used to coat valves and seals in pipes at the uranium enrichment plant in Oak Ridge, TN.
Chemical resistance
The only substances to affect the carbon-fluorine bonds of PTFE include alkali metals (molten or in solution.) Also, rare fluorinated compounds at high temperatures and/or pressures such as xenon difluoride and cobalt (III) fluoride can attack these bonds. Aluminum and magnesium at high temperatures will also damage them.
TFE has one of the lowest coefficient of friction of any solid. Therefore, it is almost impossible to glue something to Teflon (PTFE) no matter the material or glue that’s used.
Temperature
Teflon is a polymer with a melting point of 326ºC or 620ºF. In addition, it also maintains its properties such as high strength, toughness and self-lubrication at the very low temperatures of -268º C or -450º F. At temperatures, above 650º C or 1200º F, PTFE will undergo depolymerization. Teflon® is nonflammable.
What else is Teflon used for? Find out here in Craftech Industries’ blog.
Craftech Industries, Inc.
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Filed Under: Screws • nuts • bolts • rivets