How to Ensure Optimum Performance of Rubber Seals in Low-temperature Environments?

May 09, 2016 Food Grade Seals | Rubber Seals

Low temperature applications raise several concerns for seal manufacturers. Various industries such as railroad, automotive, and manufacturing demand optimum seal performance in low temperature and cold environments. For this reason, manufacturers need to employ tests and standards to evaluate the properties of rubber seals in cold temperatures.

The Trouble with Low Temperature

Low temperature applications test the reliability of seals. When exposed to low temperatures, elastomeric seals tend to contract. This can lead to decreased compression and leakage. In order to provide perfect sealing, rubber seals must be able to contract. Whereas, in lower temperature applications that are above their designated limits, seals become brittle and rigid. Moreover, the seal will undergo a compression set, and will allow for leak when reheated beyond the low temperature.

Avoiding Seal Failure by Conducting Low-temperature Testing

Various tests are conducted to determine the low-temperature characteristics of a specific rubber compound.. Three standard low-temperature tests are used to measure the physical characteristics and performance of a seal material:

Brittleness: Also referred to as ASTM D2137, this test is employed to measure the ability of a rubber seal to withstand breaking. To test the brittleness, a material is bent at a given temperature for a specific period of time.
Torsional Stiffness Ratio: Also referred to as ASTM D1053, this test is conducted to measure the stiffness ratio of seal material. To determine the torsional stiffness ratio, the material is first twisted at room temperature and then at a specific lower temperature.
Temperature Retraction: Also known as ASTM D1329, this method is used to measure the temperature at which a frozen rubber seal can return to its original elastic state.

some other tests used for seal testing are the ASTM D2240 Durometer Test and the ASTM D7426 Glass Transition Test. These tests have limited value for seal applications, as they provide a general evaluation of seal performance at low temperature.

Low temperature environment can have a negative impact on the performance of rubber seals. This is why stringent testing is essential to ensure the success of seals in cold environments.