ASTM D2000 HK
SAE J 200 Codes
Relative Cost High
Automotive fuel handling
Aircraft engine seals
High temperature applications requiring good compression set
General industrial seals and gaskets
Perform Well in…
Fuel or blend with methanol or ethanol
Diesel or blend with biodiesel
Mineral oil and grease
Silicone oil and grease
Ozone, weathering and very high temperature air
Doesn’t Perform Well in…
Low molecular wieght esters and ethers
Hot hydrofluoric or chlorosulfonic acids
Phosphate ester based hydraulic fluids – Skydrol®
FKM were introduced in 1957 (Dupont - Viton®). In general all fluorinated polymers are highly fluorinated hydrocarbon polymers. They are very stable and possess exceptional resistance to oxidation, weather, flame, oil, chemical attack and swelling in a wide range of liquids.
Fluorocarbon exhibits resistance to a broad range of chemicals combined with very good high temperature properties more so than any of the other elastomers. It is the closest available approach to a universal elastomer for sealing in the use of O-rings and other custom seals over other types of elastomers. FKM can be classified in
many subgroups according to:
1. Fluorine content: general type (A—66%), middle fluorine content type (B&GBL—69%), high fluorine content type (F&GF—70%), improving low temperature flexibility type (GLT, GFLT) and excellent resistance to more chemicals and solvents (ETP & FFKM). The higher the fluorine content the better the chemical resistance.
2. Polymer: A—dipolymer, B, F and GF—terpolymer.
3. Cure system: standard FKM compounds are bisphenol cured. FKM compounds with peroxide-cured possess better acid solution resistance than the bisphenol cured.
Excellent chemical resistance
Excellent heat resistance
Good mechanical properties
Good compression set resistance
Depending on structure and fluorine content (65% to 71%) FKM materials can differ with regards to their chemical resistance and cold-flexibility. The chemical resistance improves with increasing fluorine levels. However, as the fluorine content increases the low-temperature flexibility of polymer decreases. For low-temperature application special FKM types have been developed.