What are the low temperature resistant seal materials for pneumatic actuators?

In outdoor operations in regions such as Northeast China and Inner Mongolia, pneumatic actuators are often required to withstand low-temperature environments. In extremely cold conditions like the Russian Far East or Siberia, even higher demands are placed on the cold resistance, elasticity, and sealing performance of sealing ring materials. Common low-temperature resistant sealing ring materials mainly include the following categories:

Nitrile Rubber (NBR): This is the most common type, capable of withstanding temperatures down to -40°C, with special formulations tolerating -55°C. NBR offers good oil resistance and is a widely applicable sealing material for pneumatic actuators.

Fluoroelastomer (FKM): Standard FKM has limited low-temperature resistance (approximately -20°C to -30°C). Improved formulation low-temperature FKM types (e.g., GLT, GFLT series) can be suitable for -40°C or even -50°C, while maintaining good oil and chemical corrosion resistance. These modified FKMs are suitable for northern Chinese regions .

Silicone Rubber (VMQ): Silicone rubber exhibits excellent low-temperature resistance. Standard grades remain elastic at -60°C, with some special silicones resisting down to -70°C. It has a low compression set and good resilience, but relatively weaker mechanical strength and abrasion resistance, making it suitable for static or low-speed dynamic sealing applications .

Ethylene Propylene Diene Monomer (EPDM): EPDM generally shows good low-temperature performance, typically withstanding around -50°C. However, EPDM is relatively sensitive to oily air sources and prone to premature aging, so its selection requires caution regarding lubricants in the system .

Polytetrafluoroethylene (PTFE) and Derived Materials: Pure PTFE sealing materials remain stable at very low temperatures down to -200°C. However, pure PTFE is brittle and not suitable for applications with frequent or high-speed operation .

Perfluoroelastomer (FFKM): FFKM combines the chemical inertness of FKM with excellent low-temperature elasticity. Some grades can withstand -30°C to -40°C, making them suitable for high-end pneumatic systems requiring high purity, strong corrosion resistance, and certain low-temperature capabilities .

The selection and application of the aforementioned low-temperature resistant sealing rings should depend on various factors, including the actual operating environment temperature, actuator operating speed and frequency, oil content in the compressed gas, cleanliness of the air source, and procurement costs.