| Property | Value |
|---|---|
| Temperature range | -40 °C to +125 °C |
| Hardness | 50–90 Shore A |
| Best at | Fuel and oil resistance with low permeability and cold flexibility |
| Contains fluorine | No |
Why fuel systems specify it
A fuel line has to resist the fuel, resist the heat under a hood, stay flexible in a cold start, and not let vapour permeate out through the wall. Nitrile handles the fuel but permeates and stiffens in the cold. Butyl handles the permeation but dissolves in the fuel. ECO does all four adequately, and adequately across four requirements is what the application needs.
Homopolymer (CO) has the lowest permeability; copolymer (ECO) trades a little of that for better low-temperature behaviour. Which one is right depends on whether the governing requirement is vapour loss or a cold start.
How we compound and test it
Epichlorohydrin releases trace acid as it ages at temperature, which can corrode metal parts in contact with it. An acid acceptor in the formulation handles this, and leaving it out is the classic way to produce a part that works on the bench and pits the housing it is bonded to. Every ECO compound we mix carries one.
We verify fuel and oil resistance by immersion in the actual fluid where a customer can supply it, rather than by a standard reference oil that may not represent the service. Fuel blends vary, and ethanol content in particular changes swell behaviour.
The two mistakes buyers make
The first is bonding it to bare metal without accounting for the acid. The part is fine; the mating component corrodes.
The second is specifying it on cost grounds against nitrile without the permeation requirement in hand. If vapour loss is not a requirement, nitrile is cheaper and often sufficient. ECO earns its price only when permeability or cold flexibility is genuinely in the spec.
Typical uses
- Fuel hose, fuel system seals and diaphragms
- Vapour-barrier parts in automotive service
- Air ducts and emissions-control components
- Cold-climate oil and fuel service
- Parts needing nitrile chemistry with butyl permeability