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Electronic Encapsulants: Silicone, Epoxy and Polyurethane Potting Compounds

 

Encapsulation is a protection technique that consists of embedding electronic components in a resin to protect them against mechanical, thermal, chemical and dielectric stresses. The choice of encapsulant can directly influence the long-term performance of the module.

Samaro distributes a broad range of solutions, including DOWSIL™ and SYLGARD™ silicone materials from Dow, ARALDITE® epoxy resins and ARATHANE® polyurethanes from Huntsman, as well as ELECTROLUBE potting and electronic protection solutions.

 

Why encapsulate electronic components?

Electronic encapsulation addresses four major challenges in industrial electronics:

  • Mechanical protection: helps absorb shocks, vibrations and thermal expansion stresses that may damage solder joints or components.
  • Protection against moisture and contaminants: helps reduce the risk of corrosion, leakage currents and short circuits caused by condensation or process fluids.
  • Electrical insulation: helps maintain dielectric strength between conductors and prevent arcing in high-voltage modules.
  • Thermal management: thermally conductive encapsulants help transfer heat generated by components towards a heat sink or surrounding structure. encapsulants

 

Is silicone a thermal insulator?

Standard silicone is a good electrical insulator but has relatively low thermal conductivity, typically around 0.2 W/m·K according to the source document.

Thermally conductive silicones are specifically formulated with mineral fillers such as alumina, boron nitride or aluminium nitride to increase thermal conductivity, with some formulations reaching approximately 2–3 W/m·K.

The DOWSIL™ TC range includes silicone materials specifically developed for thermally conductive encapsulation applications.

 

What types of electronic encapsulants are available?

DOWSIL™ / SYLGARD™ silicones and gels

DOWSIL™ and SYLGARD™ silicone gels retain a high level of flexibility after curing, making them suitable for applications exposed to significant thermal cycling or vibration.

SYLGARD™ 184 is used for the encapsulation of sensors, LEDs, PCBs and other electronic components.

The thermally conductive DOWSIL™ TC range includes products such as TC-6015, TC-6020, TC-4530 and TC-5026, developed for thermal management applications including power modules, inverters and converters.

 

When selecting an encapsulant, I first look at the conditions the module will actually face: thermal cycling, vibration, moisture, electrical requirements, thermal dissipation needs and the geometry to be filled. Silicone, epoxy and polyurethane systems do not respond to these constraints in the same way. Viscosity, casting method and curing process also need to be considered. Our role is to bring these parameters together to identify a solution suited to both the component and the manufacturing process
Thomas Brunet
Adhesives Brand Manager at Samaro

ARALDITE® epoxy resins

ARALDITE® epoxy resins and ARADUR® hardeners cover high-performance encapsulation applications requiring high mechanical rigidity and good dielectric properties.

They can be used for applications such as transformers, relays, high-voltage modules and power components. Depending on the system, viscosity can also be adapted to gravity or vacuum casting processes. encapsulants

 

ARATHANE® polyurethanes

ARATHANE® polyurethane systems from Huntsman retain a degree of flexibility after curing, which can be beneficial for modules exposed to repeated mechanical stresses.

They are less rigid than typical epoxy systems and can therefore offer greater tolerance to deformation, depending on the formulation and application. The source document identifies automotive electronics, portable equipment and embedded sensors among the potential applications. encapsulants

 

ELECTROLUBE

The ELECTROLUBE range complements these technologies with epoxy, polyurethane and acrylic potting resins, conformal coatings and electronic maintenance products.

These solutions are used across industrial electronics, defence, medical and automotive applications. encapsulants

 

Thermally conductive DOWSIL™ TC solutions available from Samaro

  • DOWSIL™ TC-6015: two-component thermally conductive silicone for applications including power modules and inverters.
  • DOWSIL™ TC-6020: low-viscosity thermally conductive silicone encapsulant suitable for vacuum or gravity casting. View DOWSIL™ TC-6020
  • DOWSIL™ TC-4530: flexible thermally conductive silicone gel for applications exposed to frequent thermal cycling.
  • DOWSIL™ TC-5026: thermally conductive silicone compound for thermal interface and light encapsulation applications. View DOWSIL™ TC-5026

 

These product descriptions reproduce the positioning contained in the supplied document. encapsulants

For a broader overview of electronic protection and thermal management technologies, visit our Electric & Electronic Protection & Assembly page.

FAQ

How do you choose an electronic encapsulant?
The choice depends on the module requirements: temperature, vibration, moisture, electrical performance, thermal dissipation needs and the geometry to be filled. The casting and curing process should also be taken into account.
Silicone, epoxy or polyurethane: which technology should you choose?
Silicone is well suited to applications requiring flexibility and tolerance to thermal cycling. Epoxy provides greater mechanical rigidity, while polyurethane can be a good option when some flexibility is required.
When should you use a thermally conductive encapsulant?
A thermally conductive encapsulant is relevant when the potting material contributes to transferring heat away from the components. Thermal conductivity should be considered together with the module geometry and the overall thermal path.
Why is viscosity important for electronic potting?
Viscosity affects how easily the resin flows around components and fills complex areas. It should be selected according to the module geometry and the casting process used.
How can you reduce air bubbles during electronic potting?
Mixing conditions, dispensing method and, depending on the system, degassing or vacuum casting can help reduce trapped air. Processing conditions should be defined according to the product’s technical data sheet.