FKM 4 - Fluoroelastomer terpolymer of tetrafluoroethylene, propylene & vinylidene fluoride

Clwyd referenceFKM 4
ASTM classificationFKM 4

Terpolymer of tetrafluoroethylene (TFE), propylene (P) and vinylidene fluoride (VF2/VDF). While base resistance is increased in type 4 FKMs, their swelling properties especially in hydrocarbons are worsened. Typically they have a fluorine content of about 67 weight percent.

Typical applications
Advantages
Disadvantages
Available hardness range (Shore A)60 - 95
Upper continuous service temp.250°C
Min. temp. for sealing applications-5°C
Minimum non-brittle  temp. -10°C
Tensile strength (up to)20 MPa
Elongation at break (up to)250%
Price BracketMedium
ASTM 1 OilExcellent
ASTM 2 OilExcellent
ASTM 3 OilExcellent
KeroseneExcellent
Liquid BExcellent
Liquid 101Excellent
Phosphate esterNone
KetoneNone
TolueneExcellent
Iso-octaneExcellent
MethanolExcellent
Acid (weak)Excellent
Acid (strong)Excellent
Base (weak)None
Base (strong)None
Hydrogen sulphideNone
SteamNone
OzoneExcellent
RadiationExcellent
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