FEP ENCAPSULATED O-RINGS Viton® Core with FEP Jacket.

Description: This choice gives the best possible sealing characteristics due to the very
low compression values of the specially formulated Viton Core. Unless there are
extreme high or low temperatures involved, Viton core should be the first choice.
FEP Encapsulated "O" Rings are solvent resistant and chemically inert (except for attack
by alkaline metals, fluorine and some halogenated compounds at high temperatures) yet
have an elastomeric memory near that of rubber "O" Rings. FEP polymer, also, has an
extremely low coefficient of friction (0.1 to 0.2) and very low permeability to gases,
making Chem-Rings a virtually universal seal for use in hostile environments.

Limitations: Dynamic use where high speeds and poor finishes are encountered.
Where the housing design requires excessive stretch or collapse of the O-ring during
installation.

Chemistry: FEP (fluorinated ethylene propylene) is a copolymer of hexafluoropropylene
and tetrafluoroethylene. It differs from the PTFE (polytetrafluoroethylene) resins in that it
is melt-processible using conventional injection molding and screw extrusion techniques.
Fluorinated ethylene propylene was invented by DuPont and is sold under the
brand name Teflon.

Temperature Range: -20° to 204°Celcius

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FEP ENCAPSULATED O-RINGS Silicon Core with FEP Jacket.

Description: Whilst technically inferior to Viton as a seal Material, Silicone does have
the ability to work at lower temperatures than Viton. FEP Encapsulated "O" Rings are
solvent resistant and chemically inert (except for attack by alkaline metals, fluorine and
some halogenated compounds at high temperatures) yet have an elastomeric memory
near that of rubber "O" Rings. FEP polymer, also, has an extremely low coefficient of
friction (0.1 to 0.2) and very low permeability to gases, making Chem-Rings a virtually
universal seal for use in hostile environments.

Limitations: Dynamic use where high speeds and poor finishes are encountered.
Where the housing design requires excessive stretch or collapse of the O-ring during
installation.

Chemistry: FEP (fluorinated ethylene propylene) is a copolymer of hexafluoropropylene
and tetrafluoroethylene. It differs from the PTFE (polytetrafluoroethylene) resins in that it
is melt-processible using conventional injection molding and screw extrusion techniques.
Fluorinated ethylene propylene was invented by DuPont and is sold under the
brand name Teflon.

Temperature Range:-60° to 204°Celcius

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SILICONE

Description: Excellent material for static service at extreme (hot or cold) temperatures.
Outstanding flex and fatigue life. Very good for ozone and UV radiation service as well
as for resistance to fungal and biological attack.

Limitations: Avoid chlorinated solvents, aliphatic and aromatic hydrocarbons and
petroleum oils. Silicones are generally very permeable to gases and have poor physical
strength and abrasion resistance.

Chemistry: Methyl disiloxane, with vinyl— and/or phenyl—groups.

Temperature Range:-115° to 232°Celcius

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EPDM

Description: Excellent resistance to water, steam and polar solvents, as well as ozone
and sunlight. Also resistant to alcohols, glycol engine coolants and SKY-DROL
(phosphate ester hydraulic fluid).

Limitations: Avoid non-polar solvents, petroleum oils, and aromatic fuels.

Chemistry: Copolymer of ethylene and propylene, or terpolymer with butadiene.

Temperature Range:-55° to 150°Celcius

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