Which Elastomer Offers The Best Oil & Fuel Resistance?
In today’s industries, rubber products are required to operate in both challenging and hostile environments. There is often a requirement for these products to operate in and around oil and fuel and, as such, it is important that recommendations are able to be made in regards to the most appropriate materials which are best suited to performing in such environments.
In selecting a rubber for use in any particular application, it is necessary to hold a strong understanding of the following:
- Mechanical Properties (hardness, tensile strength, extensibility, flex cracking resistance, tear resistance & abrasion resistance)
- Operating Temperature Range
- Resistance To Heat, UV, Oxygen, Ozone & Miscellaneous Chemicals
- Economic Restrictions / Cost
Selecting the correct elastomer for a particular application alongside ‘compounding’ it with ingredients which will fine tune many of the above properties is essential and something which White Cross Rubber Products pride themselves on.
Primarily utilising 12 different elastomers for the manufacture of both rubber sheeting and rubber coated textiles, our technicians are on hand to help inform decisions and to help make the research stage that little bit more straight forward.
Below you’ll find a comparison of our 12 most commonly utilised elastomers based upon their oil and fuel resistant properties, graded ‘Poor’ to ‘Excellent.’
Please note: Whilst most main rubbers are outlined below, our capabilities and experience allow us to manufacture a much wider range of blends and formulations. The inherent characteristics of a polymer can be improved through the inclusion of additives, including the oil and fuel resistance properties.
|Elastomer||Oil Resistance||Fuel Resistance|
|Polyurethane||Good / Excellent||Good|
|Vamac||Good||Poor / Fair|
|Hypalon||Fair||Poor / Fair|
|Neoprene||Fair||Poor / Fair|
|Silicone||Poor / Fair||Poor|
|Thermoplastic Elastomer||Poor / Fair||Poor|
For the best oil and fuel resistance, the options from the above are clearly Nitrile, Epichlorohydrin and Viton and on balance, all three elastomers will perform adequately in this environment. Nitrile is regarded as the ‘industry workhorse,’ a general commodity material which performs very well in environments where there is an exposure to oil and or fuel. The base elastomer is readily available in a variety of acrylonitrile levels which allows the rubber chemist to formulate a wide variety of material types which broadly offer trade-offs in oil and fuel resistance verses low temperature flexibility. It has good general mechanical properties, a reasonable operating temperature range and will undoubtedly be the most economical from the three choices. The weakness of Nitrile, however, is that the polymer is susceptible to oxidative ageing and ozone attack. This can be improved by blending with PVC or by removing the unsaturation present to produce Hydrogenated Nitrile (HNBR or HSN).
Epichlorohydrin is viewed as a more specialist elastomer and hence comes in at a more costly alternative to Nitrile. The base elastomer is available in a range of options which allows for trade-offs in oil and fuel resistance versus low temperature flexibility and it too offers good mechanical properties, a wider range of operating temperatures in comparison and its saturated polymer structure offers resistance against oxidative ageing and ozone attack.
Lastly, Viton is often seen as the best performing elastomer and will be selected either Nitrile or Epichlorohydrin are unsuitable. Again, this poses a more costly option however in certain usage environments may be the only suitable elastomer. The base elastomer is available in differing fluorine content which again offers a trade-off between oil and fuel resistance versus low temperature flexibility. A number of speciality elastomers are also offered to cover low temperature usage requirements. Viton offers reasonable mechanical properties, can operate up to 250°C, has excellent oxidative and ozone resistance and is resistant to a wide range of chemicals. The main drawback is it’s higher price point and it’s low temperature performance.
In many cases, material selection needs to be a compromise with a number of different factors coming into play, not forgetting the economics of a particular situation.
Should you be looking for more in-depth, backed up information and data surrounding the oil resistance of any number of our main elastomers, we welcome you to give our technicians a call on 01524 585200 where we will be only more than happy offer guidance and assistance.