| Property | Value |
|---|---|
| ASTM D1418 designation | FEPM |
| Temperature range | -10 °C to +200 °C, briefly higher |
| Hardness | 60–90 Shore A |
| Cure system | Peroxide |
| Contains fluorine | Yes — in scope of current PFAS definitions |
Where AFLAS beats FKM
FKM is the better-known fluoroelastomer and the better choice for most fuels and oils. But FKM is attacked by steam, hot water, strong bases, and amines, and those are exactly the conditions where AFLAS holds. In high-pressure steam, in caustic service, in amine-inhibited oilfield fluids, and in sour gas, AFLAS is frequently the only elastomer that survives at all.
It also performs well electrically and resists explosive decompression better than most fluoroelastomers, so it turns up downhole and in wellhead seals.
Where FKM beats AFLAS
- Fuels, aromatic solvents, and most hydrocarbons
- Low-temperature flexibility, where neither is good but FKM is better
- Compression set and sealing force retention
- Availability, price, and the number of qualified grades
PFAS regulatory status
AFLAS contains fluorine and falls within the definitions used in the PFAS restrictions now moving through regulatory bodies. That does not mean it is banned today. It means programs designed to run for the next decade or more are being asked to justify keeping it, and some are choosing not to.
- The universal PFAS restriction proposal submitted to ECHA in 2023 by five European states uses a fluorine-based definition that includes fluoroelastomers as drafted. It remains under evaluation, with derogations for some uses still in discussion.
- In the United States there is no federal ban on fluoroelastomers in products. There are reporting obligations under TSCA, and several states — Maine and Minnesota among them — have phased restrictions on intentionally added PFAS in consumer products.
- Post-mold surface fluorination is a separate exposure. It is a fluorine gas treatment applied to a finished part to make it slippery or less permeable, and it introduces fluorine to a part whose polymer may have had none.
None of this is legal advice, and the position moves. Anyone specifying or de-specifying a fluoroelastomer should confirm the current status with their own regulatory counsel. What we can tell you is what the material does, what a non-fluorinated candidate does beside it, and how the two compare after real time in steam.
Replacing AFLAS, realistically
There is no drop-in. A material that matches AFLAS on steam, chemical resistance, temperature, and sealing force at the same price does not exist. What does exist is the possibility that your application does not need all four at AFLAS's level, and that is an engineering question rather than a purchasing one.
For hot-wet sealing specifically, a well-developed HNBR is the strongest non-fluorinated candidate, and it costs substantially less. Whether it is good enough for a given duty cycle has to be settled with aging data on your conditions, not with a datasheet comparison.
Typical uses
- Steam and sterilizer seals
- Oilfield seals, packers, and sour-gas service
- Caustic and amine chemical handling
- Wire and cable insulation
- High-temperature gaskets in aggressive media