Material Guide: Aflas® & Viton™Extreme

In this guide, we review both Aflas® and Viton™Extreme rubbers. These are two FEPM materials with different chemical structures giving different advantages, disadvantages and uses.

What is Aflas®?

Aflas® (also known as TFE/P) is a type of co-polymer consisting of tetrafluoroethylene and propylene, with a fluorine content of approximately 54%. It is used in many industries due to its resistance to high temperatures, bases, hydrocarbons, steam (and hot water), radiation and electrical insulating properties.

Aflas® is often chosen over other polymers for applications involving steam, sour gas and amines, as it does not contain the VF2 monomer, which is the point of chemical attack for basic media.

What are the advantages of Aflas®

Chemical resistance

  • Aflas® resists some substances that FKM’s are unable to resist, specifically, strong bases, amines, sour gas (H₂S), and polar solvents.

High-temperature resistance

  • Aflas® has a continuous working temperature range between -5°C and +200°C and is able to withstand up to 250°C for short periods.

Steam resistance

  • Aflas® is resistant to steam and hot water.

Electrical resistance

  • Aflas® has good electrical insulation properties. TRP have grades formulated specifically for electrical resistance.

Low outgassing properties

  • Aflas® releases minimal volatile compounds during exposure to high temperatures.

Weather and ozone resistance

  • Aflas’® resistance to environmental conditions and ozone makes it highly suited to outdoor applications.

What are the advantages of Aflas®

Poor low temperatures performance

  • Although Aflas® can perform well under high temperatures, it typically will not seal statically below -5°C.

Non-universal chemical resistance

  • Although Aflas® has good resistance to bases, hydrocarbons, steam, and hot water, it does not offer as broad a resistance as some elastomers, such as FKM or FFKM. For example, Aflas® does not resist ketones, aromatic fuels, or ethers well.

Which applications use Aflas®?

Aflas® is frequently used within the following applications:

 

  • Chemical processing – Aflas® materials are a commonly used rubber for chemical processing as a result of its resistance to high temperatures as well as bases, and many other chemicals. For example, it is used in gaskets for hypochlorite and chlorate manufacture.
  • Food processing – Some grades of Aflas® are FDA-approved, making them suitable for various food processing applications as a food-safe polymer. Aflas® is also specified in these environments for its resistance to CIP and SIP processes.
  • Oil and gas – Aflas® is frequently used to manufacture oil seals, due to its resistance to hydrocarbons, heat and sour gas (H₂S).
  • Automotive – Aflas® materials are widely used within the automotive industry due to their high resistance to fuel and oils. They are used for automotive rubber seals in fuel systems, transmissions and engine components.

What compounds of Aflas® are available at TRP?

TRP offers a range of Aflas® compounds formulated for specific applications. Details of these materials can be found in our material datasheets.

For example, F336 is formulated for FDA 21 CFR 177-2600 (e)(f) compliance, meaning that it can be used with fatty and aqueous foods. It also exhibits reliable resistance to acids, bases, steam, hot water, and amines.

Frequently asked questions about Aflas®

  • Are Aflas® and Viton™Extreme™ both FEPM polymers?

    Aflas® and Viton™Extreme are branded names for FEPM materials produced by AGC Chemicals and DuPont, respectively. They differ in the polymeric structure which give different properties for each material. 

What is Viton™Extreme?

Viton™Extreme is a FEPM material that is often used in environments involving extreme temperatures and aggressive chemicals. It is a type of Fluoropolymer created without the use of a VF2 monomer. This gives Viton™Extreme improved resistance to strong bases. 

What are the properties of Viton™Extreme?

High-temperature resistance

  • Viton™Extreme is able to withstand high temperatures, with the polymer having a temperature range between -10°C and 200°C (with excursions to 250°C).

Superior chemical resistance

  • Viton™Extreme has good resistance to a broad range of chemicals, including acids, ketones, amines, aldehydes, hydrocarbons and low-molecular-weight esters.

Compression set resistance

  • This elastomer is designed for improved seal performance, meaning it has a good resistance to compression set and excellent physical properties.

Good resistance to bases

  • Viton™Extreme has good resistance to bases and high pH fluids; it also has a low volume change in amines, hot water and highly caustic solutions.

What are the disadvantages of Viton™Extreme?

Higher cost

  • In comparison to other polymers, particularly the standard version of Viton.

Poor low temperature performance

  • although Viton™Extreme is marginally better in this department compared to other FEPMs, such as Aflas®, it still has poor low temperature performance.

Non-universal chemical resistance

  • although Viton™Extreme has good resistance to specific substances, the broader chemical resistance of FKM may be more suitable for some applications. It does not have the universal chemical resistance of FFKM.

Which applications use Viton™Extreme?

Viton™Extreme is suitable for use in the following applications:

  • Oil and gas – Viton™Extreme resists many oils and fuels, meaning it is often used for oil seals. It also has good resistance to sour gas (H₂S).
  • Chemical processing – Viton™Extreme is often used as a rubber for chemical processing due to its resistance to acids, ketones, amines, and hydrocarbons . 
  • Automotive – Viton™Extreme™ is used as a polymer for automotive rubber seals due to its strong resistance to oils and fuels.
  • Aerospace – Viton™Extreme is used for aerospace seals due to its resistance to many aircraft fuels and the high temperatures experienced within aerospace applications.

What compounds of Viton™Extreme are available at TRP?

For more details about Viton™Extreme please see our data sheet for our F243 Viton™Extreme compound.

If you would like to find out about Viton™Extreme or any of our available polymers or products, please get in touch with one of our engineers today.

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