Rising operating temperatures and the miniaturisation of electronic devices are making thermal management one of the key challenges in modern design within the electronics sector and beyond.
PCBs, inverters, power supplies, automotive modules and power electronics systems now operate under increasingly severe conditions, where heat can directly compromise the reliability, performance and lifespan of the system. When heat transfer is not optimised, the risk is not limited to the immediate overheating of the component. Over time, the following may occur:
- premature degradation;
- operational instability;
- loss of efficiency;
- failures caused by continuous thermal stress.
The role of silicones for thermal management
Silicones for thermal management are used specifically to improve the dissipation of heat between electronic components and heat-dissipating surfaces such as heat sinks or metal housings.
Air, in fact, is a poor thermal conductor and represents one of the main obstacles to heat transfer. The use of thermally conductive silicone materials makes it possible to eliminate these air gaps, creating a more efficient thermal path.
Which silicone formulations are used in electronics thermal management?
In the electronics sector, silicones are developed in various formulations depending on the required application:
- Thermally conductive silicone pastes;
- Gap fillers
- RTV silicone adhesives
- Printable pads;
- silicone resins.
All these formulations meet different requirements in terms of heat dissipation, vibration, environmental protection and assembly.
Among the most widely used technologies in thermal management are the solutions Dowsil™, developed for applications ranging from consumer electronics to automotive, telecommunications, LED lighting, photovoltaics and industrial electronics.
Silicone thermal conductive pastes
Silicone thermal conductive pastes are one of the most widely used technologies in the thermal management of electronic components.
These materials are generally formulated as single-component non-curing systems designed to be applied between the component and the heat sink. Their main function is to eliminate the air present between the surfaces, thereby improving heat transfer.
Silicone thermal pastes are used primarily in narrow gaps, where they can easily adapt to surface irregularities, ensuring efficient thermal contact. In the electronics sector, they are used in:
- MPU cooling;
- power modules;
- PCB assembly;
- servers;
- laptops;
- power supplies;
- automotive systems.
| Product | Description | Operating temperature (°C) | Viscosity at 23°C (mPa·s) | Color | Thermal conductivity (W/m·K) | Thermal resistance at 40 psi (°C·cm²/W) | Dielectric strength (kV/mm) |
| DOWSIL™ TC-5622 | Designed to provide efficient heat transfer for cooling modules, including MPUs used in computers and power modules. | -50°C to 177°C | 95,000 | Grey | 4.3 | 0.06 | Not specified |
| DOWSIL™ TC-5351 | Suitable for use as a thermally conductive material in power electronics. | -50°C to 177°C | 300,000 | Grey | 3.3 | 0.25 | 6.3 |
| DOWSIL™ TC-5629 | High-thermal-conductivity solution for LED lighting and other electronic applications. | Not specified | 295,000 | Grey | 3.2 | N/A | 6.3 |
| DOWSIL™ SC-4476 | Provides efficient heat transfer for cooling PCB assemblies. | Not specified | 310,000 | Grey | 3.1 | N/A | 25 |
| DOWSIL™ TC-5026 | Designed to provide efficient heat transfer for cooling MPUs used in servers, desktop computers, notebooks and gaming consoles. | Not specified | 100,000 | Grey | 2.9 | 0.03 | 8.9 |
| DOWSIL™ TC-5121 CLV | Designed to provide efficient heat transfer for cooling MPUs used in servers, desktop computers and notebooks. | -50°C to 177°C | 79,000 | Grey | 2.8 | 0.09 | 1.9 |
| DOWSIL™ SE 4490 CV | Designed to provide efficient heat transfer for cooling automotive control modules, power supplies and display driver ICs. | -50°C to 177°C | 520,000 | White | 1.9 | 0.77 | 4 |
| DOWSIL™ TC-5080 | Suitable for use as a thermal interface material for power supplies and power components in the transportation sector. | -50°C to 177°C | 836,000 | White | 1 | 0.2 | 8.7 |
| DOWSIL™ SC102 | Designed for cooling modules assembled on PCBs. | -50°C to 177°C | 29,000 | White | 0.9 | 0.62 | 2 |
| DOWSIL™ 340 Heat Sink Compound | Designed for the thermal coupling of electrical devices and PCB assemblies. | -50°C to 177°C | 542,000 | White | 0.67 | 0.16 | 8 |
Silicone gap fillers
Silicone gap fillers are used when the distance between a component and a heat sink exceeds 1 mm, or when the electronic system is subject to severe vibrations and continuous thermal cycling.
Unlike traditional thermal pastes, these materials are generally two-component and cure after mixing. Although they are not structural adhesives, they retain a tacky surface which improves the stability of the material over time, reducing the risk of pump-out (degradation)
This technology is used primarily in the automotive sector, in battery packs, inverters, power modules and control units, where dimensional tolerances and operating conditions require more stable and conformable materials.
| Product | Description | Standards / Approvals | Operating temperature (°C) | Viscosity at 23°C (mPa·s) | Color | Thermal conductivity (W/m·K) | Shore hardness | Cure time | Dielectric strength (kV/mm) |
| DOWSIL™ TC-4525 CV | Silicone designed to transfer heat from components mounted on printed circuit boards to the heat sink, providing a reliable cooling solution for modules such as engine and transmission control units. | UL 94 V-0 | -45°C to 150°C | 217,000 | White/Blue | 2.5 | 40 Shore OO | 120 min at 25°C; 20 min at 50°C; 10 min at 80°C | 12 |
| DOWSIL™ TC-4015 | Thermal pads for microchips and power supplies that facilitate heat dissipation, ensuring reliable performance and ease of assembly. | UL 94 V-0 | -45°C to 150°C | 180,000 | White/Blue | 1.5 | 55 Shore OO | 150 min at 25°C; 30 min at 80°C | 15.8 |
| DOWSIL™ TC-4535 CV | Designed to transfer heat from PCB assemblies to the heat sink, providing a reliable cooling solution for modules such as engine and transmission control units. | UL 94 V-0 | -45°C to 200°C | 205,000 | White/Blue | 3.4 | 52 Shore OO | 120 min at 25°C | 22 |
Thermally conductive silicone resins for encapsulation and potting
In many electronic applications, simply dissipating heat is not enough.
PCB boards, inverters, transformers, sensors and electronic modules often have to operate in environments subject to humidity, contaminants, thermal shock and continuous vibration. In such cases, thermally conductive silicone resins are used for encapsulation and bonding.
These materials combine thermal management and environmental protection, creating a protective barrier around the electronics whilst maintaining good heat transfer capabilities.
Silicone resins are used primarily in automotive, electronics and photovoltaic applications, where long-term reliability and stability are essential.
| Product | Description | Standards / Approvals | Operating Temperature (°C) | Viscosity (mPa·s) at 23°C | Color | Thermal Conductivity (W/m·K) | Shore Hardness | Cure Time | Dielectric Strength (kV/mm) |
| Dowsil™ TC-6020 | Suitable for industrial power modules and the thermal management of automotive control units. | UL94 V-0 & UL RTI 150°C | -45°C to 200°C | 10,640 | Gray | 2.72 | 63A | 24 hours at 25°C; 13 min at 80°C | 24.1 |
| Dowsil™ TC-4605 | Encapsulant/resin for electronics that provides protection under different environmental conditions and thermal management. | – | -45°C to 200°C | 2,900 | Gray | 1 | 30A | 1 hour at 120°C | 21 |
| Dowsil™ SE 4430 | Used for cooling electronic modules in power supply applications. | – | -45°C to 200°C | 6,700 | Gray | 0.96 | 70 OO | 7 hours at 25°C; 2 min at 150°C | 18 |
| Sylgard™ 164 | Suitable as a general-purpose potting material for power supplies, connectors, sensors, industrial controls, transformers and amplifiers. | UL94 V-0 & UL RTI 150°C | -45°C to 200°C | 9,100 | Gray | 0.64 | 61A | 40 min at 25°C | 19 |
| Dowsil™ CN-8760 | Designed for photovoltaic applications, inverters, power units and sensors. | UL94 V-0 | -45°C to 200°C | 2,850 | Gray | 0.66 | 52A | 24 hours at 25°C; 40 min at 50°C | 26 |
| Sylgard™ 160 | Suitable as a general-purpose potting material for power supplies, connectors, sensors, industrial controls and transformers. | UL94 V-0 & UL RTI 150°C | -45°C to 200°C | 4,865 | Gray | 0.62 | 56A | 24 hours at 25°C; 4 min at 100°C | 19 |
| Dowsil™ EE-3200 | Successfully tested in solar inverters, where it provides high protection for sensitive components against repeated mechanical and thermal stress, as well as moisture and other harsh environmental factors. | UL94 V-0 & UL RTI 150°C; EN45545: R22 to R26 HL3 | -45°C to 200°C | 1,700 | Gray | 0.5 | 20 OO | 3 hours at 25°C; 20 min at 50°C | 14 |
| Sylgard™ 170 | Suitable for use as an encapsulant or potting material. | UL94 V-0; MIL Spec | -45°C to 200°C | 2,135 | Gray | 0.48 | 47A | 24 hours at 25°C; 10 min at 100°C | 18 |
Thermally conductive silicone adhesives
Thermally conductive silicone adhesives combine heat dissipation and mechanical bonding in a single solution. These materials are used for the assembly of heat sinks, electronic substrates, PCBs and power components, helping to improve both the heat transfer and the structural reliability of the system.
In the automotive and electronics sectors, they are particularly widely used in control modules, power supplies, telecoms systems and high-density electronic applications.
Some systems utilise RTV silicone technologies, whilst others are developed for heat-cure processes that allow for faster and more controlled cross-linking.
| Product | Description | Standards / Approvals | Operating temperature (°C) | Viscosity at 23°C (mPa·s) | Color | Thermal conductivity (W/m·K) | Shore hardness | Tensile strength (MPa) | Elongation (%) | Dielectric strength (kV/mm) |
| DOWSIL™ SE 4485 | Designed for module cooling. | UL 94 V-0 | -45°C to 200°C | N/A | White | 2.8 | 90 Shore A | 3.4 | 20 | 19 |
| DOWSIL™ SE 4486 CV | Designed for cooling electronic modules, including household appliances. | – | -45°C to 200°C | 196,00 | White | 1.6 | 81 Shore A | 3.9 | 43 | 20 |
| DOWSIL™ SE 4420 | Designed for cooling electronic modules, including telecommunications equipment and power supplies. Thermally conductive RTV silicone adhesive. | – | -45°C to 200°C | 108,000 | White | 0.92 | 76 Shore A | 4.1 | 77 | 14.6 |
| DOWSIL™ EA 9189H | Alkoxy-curing RTV adhesive used for module assembly. | UL 94 V-0 | -45°C to 200°C | N/A | White | 0.88 | 80 Shore A | 3.9 | 32 | 28 |
| DOWSIL™ SE 9184 | Designed to provide adhesion and heat transfer for cooling various electrical components. | UL 94 V-0 | -45°C to 200°C | N/A | White | 0.84 | 74 Shore A | 3.2 | 60 | 20 |
Silicones for thermal management in modern electronics
In the electronics sector, silicone solutions for thermal management are developed in various formulations depending on the required application. Silicone thermal pastes, gap fillers, RTV silicone adhesives and silicone resins meet different requirements in terms of heat dissipation, vibration, environmental protection and assembly.
Each technology is designed for specific operating conditions and for different types of electronic components, ranging from PCBs and power modules to inverters, power supplies and automotive systems.
For further information, please contact our experts at MD Poland.
