FKM O-Ring and seal performance cost benefit
makes it the second most popular sealing material. Fluoroelastomer
(FKM) offers a wide range of resistance to chemicals, oil and heat,
with situational service life above 200°C. The outstanding heat
stability and excellent resistances are due to the high ratio of
fluorine to hydrogen, the strength of the carbon-fluorine bond, and
the absence of unsaturation. FKM compounds are widely used in
chemical, automotive, aerospace and industrial applications.
Fluoroelastomers are referred to generically as FKM polymers per
the nomenclature noted in ASTM
D1418. Features Of FKM
O-Rings:
Situational service life above
200°C
Excellent resistance to acids,
fuels, mineral and vegetable oils and greases, aliphatic, aromatic
and chlorinated hydrocarbons, non-flammable hydraulic fluids (HFD)
and many organic solvents and chemicals.
Excellent resistance to aging and
ozone.
Low gas permeability, low
compression set.
Limitations of FKM
O-Rings:
Ketones (MEK,and Acetone) and
Skydrol fluids.
Amines and Anhydrous
Ammonia.
Low molecular weight esters and
ethers. Hot hydrofluoric or chlorosulfonic acids and low molecular
weight organic acids (formic and acetic
acids).
