FKM - Fluoroelastomers
Fluoroelastomers or Fluorocarbons (FKM), also known as Viton®, are highly fluorinated polymers that are suitable for continuous use at elevated temperatures. Various grades are available, including copolymer and terpolymers. The most common grades consist of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.
Fluoroelastomers have excellent heat and flame resistance, and outstanding resistance to aging, ozone, oxidizers, oils and many chemicals. They also have low gas permeability and low compression set. However, they usually have only limited low temperature capabilities; although some special lower temperature grades are available. They also have limited resistance to steam, hot water and (very) polar fluids such as strong organic acids (e.g. formic acid), methanol, ketones, ammonia and some amines, whereas new peroxide cured grades have somewhat improved chemical resistance. Furthermore, they are expensive and, thus, are only used when the components have to withstand especially harsh environments.
COMMERCIAL FKM Elastomers
Important manufacturers and suppliers of fluoroelastomers (fluorocarbons, FKM) are Du Pont, 3M, Solvay and Daikin.
Fluoroelastomer compounds are widely used in the chemical, automotive, aerospace, and energy industry. They are used for hoses, diaphragms, accumulator bladders, gaskets, O-rings and seals, all operating in especially harsh environments.
The typical service temperature of FKMs is between -20°C (-5°F) and +230°C (+445°F). They can, however, withstand temperatures up to 300°C for a short period of time. However, at high service temperatures FKMs are weak, so that the design must prevent any high loads.
- Viton® is a registered trade mark of DuPont Performance Elastomers.