A Complete Guide to Heat Stabilised Silicone Rubber

What is Heat Stabilised Silicone Rubber?

Heat stabilised silicone rubber is a type of silicone elastomer engineered to perform reliably under prolonged exposure to elevated temperatures. While standard silicone rubber can handle high heat intermittently, heat stabilised silicone is specifically formulated to retain its mechanical and physical properties during continuous exposure to extreme thermal conditions. This makes it a preferred choice for applications where thermal stability and durability are important.

Like other silicones, heat stabilised silicone rubber is based on a silicon-oxygen polymer backbone, which provides excellent thermal and chemical resistance. However, the addition of heat stabilising agents enhances its ability to withstand oxidative degradation and mechanical fatigue caused by prolonged heat exposure, thereby extending its service life.

Appearance

Initially translucent but can be pigmented to any RAL colour.

Tear Strength

  Resistance to tearing between 23N/mm and 36N/mm.

Density

  Formulated for a density at 20ᵒC of around 1.15 g/cm3.

Hardness

  Available between 24ᵒ Shore A and 79ᵒ Shore A.

Tensile Strength

  Tensile strength between 9.0g/cm3 and 11.0g/cm3.

Elongation at Break

  Flexibility between 420% and 920% without breaking.

Temperature Range

  Operates effectively between -50°C and 260°C.

Rebound Resilience

  Recovery from deformation  between 42% and 57%.

Learn how heat stabilised silicone is formulated, its benefits over general purpose silicone and common applications within the industry.

How is Heat Stabilised Silicone Rubber Made?

The production of heat stabilised silicone rubber involves a similar process to that of general silicone elastomers, but with modifications to enhance thermal performance. The process begins with the synthesis of polydimethylsiloxane (PDMS), a silicon-based polymer, through the polymerisation of siloxane precursors. This base polymer is then mixed with reinforcing fillers, such as fumed silica, to improve its mechanical strength and stability.

To achieve enhanced thermal resistance, heat stabilising additives are introduced into the formulation. These additives, often based on metal oxides or other specialised compounds, inhibit the degradation of the polymer chain when exposed to high temperatures over long periods. The selection and concentration of these stabilisers are important, as they directly influence the rubbers performance under thermal stress.

The material then undergoes a curing process, where cross-linking agents such as peroxides or platinum-based catalysts are used to vulcanise the silicone. This process solidifies the material and provides it with the necessary properties for high-heat applications. Post-curing, the rubber is subjected to stringent quality control tests to ensure it meets the required standards for thermal stability, mechanical strength and environmental resistance.

Mixing heat stabilised silicone

Advantages of Heat Stabilised Silicone Rubber

Heat stabilised silicone rubber offers several key advantages that make it indispensable in demanding thermal applications. Its primary benefit is its ability to maintain mechanical and physical integrity during prolonged exposure to high temperatures, often ranging from -50°C to as high as 260°C, depending on the specific formulation.

In addition to its thermal stability, this material demonstrates excellent resistance to oxidation, UV radiation, and ozone. This helps ensure durability in harsh environmental conditions. Its chemical resistance allows it to withstand exposure to oils, fuels and solvents without degradation. These properties make heat stabilised silicone rubber suitable for both industrial and outdoor applications.

Silicone rubber extrusions in a range of colours

The materials flexibility and elasticity are also notable. Despite its robustness, heat stabilised silicone remains pliable and can endure repeated deformation without permanent damage. This material is available in various hardness levels and can be extruded into various forms.

Common Applications and Uses

Heat stabilised silicone rubber is widely used across industries that demand reliable performance under sustained high temperatures. Below are some of the most common applications:

Industries

Example of silicone rubber being used on a car

Automotive

In the automotive industry, heat stabilised silicone rubber is a regularly used for components such as gaskets, rubber seals and hoses that must endure high engine temperatures. Its resistance to oils and thermal cycling ensures that these parts maintain their performance and integrity over time. It is also used in electrical insulation for automotive wiring systems that operate in high-heat environments.

Automotive

 Electrical

The electronics industry also benefits from the properties of heat stabilised silicone. It is often used as a protective coating for circuit boards and as an insulating material in high-temperature electronic components. Its electrical insulating properties and thermal stability make it indispensable for maintaining the reliability of sensitive electronics.

  Electrical  

Example of silicone rubber being used in an industrial setting

 Industrial

In industrial settings, heat stabilised silicone rubber is used for rubber seals, gaskets and rollers in machinery exposed to high temperatures. Its ability to perform reliably in chemical processing and high-heat manufacturing environments ensures minimal downtime and maintenance costs. Additionally, it is commonly used in industrial ovens and furnaces for insulation and sealing purposes.

Industrial

Material Compound Datasheets

Heat stabilised silicone can be extruded in a range of different hardnesses, each suitable for different applications. The properties and characteristics of these hardnesses may differ. Please see the downloadable PDF material compound datasheets for this information.

20 Shore A

30 Shore A

40 Shore A

50 Shore A

60 Shore A

70 Shore A

80 Shore A

Looking for a different grade of Silicone?

Heat stabilised silicone can be extruded in a range of different hardnesses, each suitable for different applications. The properties and characteristics of these hardnesses may differ. Please see the downloadable PDF material compound datasheets for this information.

Other Silicone Grades

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