Guide to Choosing Hightemperature Rubber Gaskets

Imagine your product operating in extreme high-temperature environments while its internal components remain perfectly protected. The unsung hero behind this reliability might be a small rubber gasket. However, choosing the right high-temperature rubber material is crucial for ensuring long-term performance under thermal stress.

In demanding applications such as electrical enclosures, electromagnetic shielding, and battery-powered electronic devices, rubber material selection becomes critical. These materials are sensitive to temperature, light, oxygen, humidity, heat, and mechanical stress. Proper material selection not only ensures gasket longevity but also guarantees end-user safety and protects product quality.

Designing high-temperature gaskets requires careful consideration of material aging, cracking, and sealing performance maintenance under thermal conditions. This process involves evaluating several key performance indicators:

ASTM standards include thermal aging tests to evaluate a rubber material's resistance to performance degradation in high-temperature environments. These tests simulate long-term usage conditions and measure material changes at various temperatures and durations.

However, passing thermal aging tests doesn't guarantee complete performance preservation. Comprehensive evaluation requires additional testing of tensile strength, elongation, compression set, and hardness.

Compression set testing evaluates a material's ability to retain elastic properties after high-temperature exposure. Extended testing reveals whether high-temperature rubber gasket materials can maintain their sealing performance.

Simply put, smaller compression set values indicate better elastic recovery and sealing effectiveness. This measurement is similar to evaluating a spring's ability to return to its original shape after prolonged compression.

These metrics reflect a material's ability to maintain its breaking point under tensile stress. Materials that become brittle at high temperatures show significant reductions in both tensile strength and elongation.

Compared to metals and composites, rubber materials generally have lower operating temperature limits. Typically, rubber gasket materials capable of withstanding 350°F (177°C) are considered high-temperature resistant. However, advancements in material science continue to push these limits higher.

The following table shows common rubber gasket materials and their maximum operating temperatures:

When searching for ideal high-temperature flexible gasket materials, fluorocarbon and silicone rubbers often emerge as top contenders. Both offer excellent high-temperature resistance but differ in other properties.

Silicone rubber remains stable at temperatures up to 500°F (260°C) before beginning to degrade. Its advantages include:

• Exceptional heat resistance
• Excellent flexibility and elasticity
• Superior weather and ozone resistance

Fluorocarbon rubber withstands temperatures up to 400°F (204°C) and offers these advantages over silicone:

• Higher tensile strength for high-pressure applications
• Better resistance to fuels, solvents, and chemicals

Choosing high-temperature rubber gasket materials requires evaluating multiple factors:

• Operating temperature: Select materials that can withstand maximum product temperatures
• Operating pressure: High-pressure applications require materials with greater tensile strength
• Contact media: Consider exposure to fuels, solvents, or chemicals
• Environmental conditions: Evaluate UV exposure, ozone levels, and humidity

Understanding different rubber materials' properties helps in making informed selections:

With excellent elasticity but poor temperature resistance (max 180°F), natural rubber suits applications like tires and basic seals.

Offering good oil resistance and operating up to 250°F, nitrile rubber works well for O-rings and fuel system components.

The premium choice for extreme conditions (400°F continuous), fluorocarbon rubber excels in aerospace and chemical processing applications.

With the highest temperature resistance (500°F) and excellent electrical properties, silicone rubber serves well in electronics and food-grade applications.