What is the best ‘O’ ring material?

Determining the “best” ‘O’ ring material is virtually impossible. It would be like picking the “best” footballer of all time. Can you really make a like-for-like comparison between a goalkeeper and a striker? No, because their roles are completely different. This is also true of different ‘O’ ring seal materials; they are designed to perform different functions. Allow TRP Polymer Solutions to talk you through three of the “best” ‘O’ ring materials for certain applications.

Our guide to different ‘O’ ring seal materials

There is a huge variety of different ‘O’ ring seal materials in use today. So much so, in fact, that for the purposes of this article we are going to focus on three of the “best” for high-performance, all-round functionality and general-purpose reliability.

FFKM ‘O’ rings – best ‘O’ ring material for high-performance

Perfluoroelastomer (FFKM) is a high-performance ‘O’ ring material that offers exceptional chemical and thermal resistance. The carbon-fluorine bonds of FFKM – known to be the strongest single bond in organic chemistry – are what give FFKM its superlative chemical, thermal and oxidation resistance.

TRP Polymer Solutions develops a wide range of impressive FFKM grades that are designed to withstand temperature extremes from as low as -55 °C to as high as +330 °C. This advanced ‘O’ ring material is suitable for applications in the chemical processing, oil and gas, aerospace and automotive industries. We can also formulate food-grade, FDA-approved FFKM ‘O’ rings specifically for use in the food and beverage sector.

Silicone ‘O’ rings – best ‘O’ ring material for all-round functionality

Silicone is a widely used ‘O’ ring material that has become somewhat of an industry standard. Silicone rubber compounds deliver very good resistance to acids, water and ozone. They also offer effective resistance to heat and weathering. Although not renowned for their tensile strength or shear resistance, certain compound grades of silicone offer improved tear resistance than standard silicones.

Silicone ‘O’ rings can operate in a broad range of temperatures, from extremely low to reasonably high – typically from around -60 °C to +250 °C. Silicone compounds are very clean and do not impart any odour or taste, which makes them an ideal choice for food, beverage and medical applications.

Nitrile ‘O’ rings – best ‘O’ ring material for general-purpose reliability

Nitrile is a popular ‘O’ ring material for a wide range of applications and industry environments. Their versatility and reliability has led to nitrile ‘O’ rings being widely regarded as an excellent choice for general-purpose applications. Nitrile ‘O’ rings are reasonably resistant to petroleum oils, crude oil, water, gasoline, propane and some hydraulic fluids.

Durable and robust, nitrile ‘O’ rings also provide good abrasion and compression set resistance. Given their general-purpose credentials, nitrile ‘O’ rings offer an unremarkable operational temperature range of -25 °C to +100 °C and relatively poor ozone and steam resistance. However, as a reliable and cost-effective solution, nitrile ‘O’ rings are a good choice, particularly for oil-resistant automotive, marine and aerospace applications.

TRP Polymer Solutions can supply ‘O’ rings in all three of these polymers and many other polymeric materials. For further information, or to discuss your application in more detail, please contact us today on +44(0)1432 268899 or email sales@trp.co.uk.