This article will help you understand what high-temperature silicone is and how it differs from regular silicone. You’ll also learn how it’s made, tested, and used in various industries—from cars and airplanes to electronics and factory machines.
What Is High-Temperature Silicone?
High-temperature silicone is a special type of silicone. It uses special formulas to withstand extreme heat.
Regular silicone can resist temperatures from -60°C to 200°C.
But high-temperature silicone can work in even hotter conditions. Most types can handle 250°C to 300°C for long periods. Some special kinds can take short bursts of heat up to 650°C.
What Are the Differences Between High-Temperature Silicone and Regular Silicone?
Some people are not sure how high-temperature silicone is different from regular silicone.
They may ask if it’s really better, or just a new name. This is a common question, especially when choosing materials for hot or harsh conditions.
High-temperature silicone is not the same as regular silicone. It is made to work in places with stronger heat and stress. Its strength, heat resistance, and long-term performance make it stand out.
The table below shows a clear comparison between regular silicone and high-temperature silicone.
| Characteristic | Regular Silicone | High-Temperature Silicone |
| Continuous Temperature Range | -60°C to 200°C | -60°C to 300°C (special formulations up to 350°C) |
| Short-Term Temperature Limit | 230°C to 250°C | 400°C to 650°C |
| Primary Fillers | Silica (SiO2) | Iron Oxide (Fe2O3), Cerium Oxide (CeO2), Alumina (Al2O3) |
| Mechanical Properties | Moderate, suitable for everyday applications | Stronger, resistant to high-temperature aging and mechanical stress |
| Cost | Lower | Higher |
| Typical Applications | Consumer goods, low-demand seals | Aerospace, automotive engines, electronic heat dissipation, industrial furnaces |
| Aging Resistance | Good, suitable for general environments | Excellent, resistant to long-term high temperatures, UV, and chemical corrosion |
What Are the Key Points in the Manufacturing Process of High-Temperature Silicone?
To produce high-performance high-temperature silicone, strict control is needed in raw material selection, formulation design, and processing methods.
Selecting the Right Silicone Rubber Base
Different silicone rubbers offer different heat resistance and mechanical properties. The choice depends on the product’s application.
In general, silicone with a higher molecular weight and specific functional groups works better for high-temperature use.
Optimizing the Formulation
The performance of high-temperature silicone depends heavily on its formulation. Several key additives are commonly used:
- Heat-resistant fillers such as silica and red iron oxide help improve thermal resistance and mechanical strength.
- Heat stabilizers slow down thermal oxidation and breakdown at high temperatures. These may include metal soaps or rare earth compounds.
- Antioxidants like hindered phenols and amines reduce aging caused by oxidation.
- Curing agents based on organic peroxides promote crosslinking at high temperatures.
Careful Mixing Process
All raw materials must be mixed thoroughly. Temperature, mixing time, and shear force must be controlled. This ensures good dispersion of fillers and the proper function of each additive.
Choosing the Right Molding Method
High-temperature silicone can be shaped through compression, extrusion, or injection.
For high-temperature and high-pressure parts, compression molding is often more reliable.
For continuous products like tubing and wire insulation, extrusion is more efficient.
Liquid silicone rubber (LSR) injection molding is also becoming popular for precise or complex parts.
Effective Curing Process
Curing is the final and most critical step. It builds the crosslinked network that gives silicone its elasticity, strength, and heat resistance. The curing temperature and time must match the formulation and part thickness.
What Are the Tests and Standards for High-Temperature Silicone?
To ensure the quality and performance of high-temperature silicone products, the industry follows specific tests and standards.
The heat aging test (ASTM D573) checks how the material changes after long-term exposure to high temperatures. It measures properties such as hardness, tensile strength, and elongation at break. This test shows how well the material holds up under heat over time.
The compression set test (ASTM D395) evaluates how much a material stays deformed after being compressed at high temperatures. This helps assess how long the sealing ability lasts.
Thermogravimetric analysis (TGA) measures the weight loss of the material during heating. It helps determine the decomposition temperature and thermal stability.
In the electronics and electrical fields, UL certification proves the product is safe and reliable. UL 94 is especially important for rating flame resistance.
Environmental regulations like RoHS and REACH ensure the material does not contain harmful substances. These standards help make the product safer and more eco-friendly.
What Are the Main Applications of High-Temperature Silicone?
High-temperature silicone plays a key role in many industries.
From cars to aircraft to electronics, this material helps improve safety, performance, and durability.
The following examples show how high-temperature silicone is used across different fields.
Automotive Industry
High-temperature silicone is especially useful in areas exposed to heat.
Cylinder Head Gasket: Engines create high heat and pressure during combustion. The gasket must seal well under these extreme conditions. Gaskets made from high-temperature silicone can maintain their shape and sealing ability for a long time. This ensures better sealing and reduces the risk of leaks.
Turbocharger Hose: Turbochargers create very hot compressed air. The hose between the turbocharger and intercooler needs to handle both heat and pressure. Regular silicone hoses may soften or deform under such stress. High-temperature silicone hoses stay strong and keep their shape better.
Aerospace Industry
The aerospace field requires materials that are both lightweight and resistant to extreme conditions. High-temperature silicone is a trusted choice here.
O-Rings for Fuel Systems: These must seal well in hot and chemically harsh conditions. High-temperature silicone can resist aviation fuels and stay flexible in high heat. Regular silicone may not hold up in such demanding situations.
High-Temperature Wire Insulation Sleeving: Aircraft wiring faces both cold at high altitudes and heat near engines. Sleeves made from high-temperature silicone offer better thermal and electrical protection. They help keep systems safe and reliable.
Industrial Equipment
Many industrial machines run in hot environments. High-temperature silicone parts help them work safely and efficiently.
Oven Door Seals: These seals keep heat inside the oven. High-temperature silicone does not crack or deform, even during long periods of baking. This keeps ovens sealed and saves energy. Regular silicone may age faster and lose performance.
Thermal Press Insulation Pads: These pads provide heat insulation and cushioning. High-temperature silicone pads can handle more heat and keep their strength longer than regular silicone.
Electronics Industry
As electronics get more powerful, heat becomes a bigger problem. High-temperature silicone helps manage this.
Potting Compound for Power Modules: These compounds protect components and help remove heat. High-temperature silicone offers better thermal conductivity and insulation than regular silicone. It keeps electronics safe in hot conditions.
Sealing Rings for High-Temperature Connectors: These rings stop moisture and dust from getting into connectors. High-temperature silicone stays strong and keeps its shape. This ensures a good seal over time.
Conclusion
Compared to regular silicone, high-temperature silicone stands out with better heat resistance and reliability. It’s built for tough environments.
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