Thermally conductive adhesives and potting compounds
February 03, 2025Understanding the key properties of thermally conductive adhesives enables engineers to design reliable, efficient thermal management systems optimized for specific structural and heat dissipation requirements.
Thermally conductive adhesives and potting compounds
Thermally conductive adhesives and potting compounds, including epoxy and silicone-based products, are vital materials in various industrial and electronic applications. These products, along with thermally conductive epoxy films designed for specific application challenges, offer versatile solutions for bonding, sealing, coating and encapsulation tasks.
Figure 1: Thermally conductive adhesives and potting compounds, including epoxy and silicone-based products, are vital materials in various industrial and electronic applications. Source: Master Bond
Advantages and applications of thermally conductive systems
Thermally conductive systems are engineered to enhance heat transfer while providing additional benefits such as mechanical strength, resistance to vibration, thermal cycling and high temperatures. These properties make them ideal for use in applications requiring heat dissipation and durability under demanding conditions.
Typical applications of these systems include:
- Bonding electronic components for effective thermal management.
- Sealing to protect against environmental factors.
- Encapsulation and coating to safeguard delicate components from mechanical stress and chemical exposure.
There are also specialty applications such as die attach, glob top, heat sink attachments, underfill encapsulants and surface mounts.
Effective properties of thermally conductive adhesives
Thermally conductive adhesives and potting compounds offer a wide array of properties tailored to meet diverse requirements. Some examples are:
- Resistance to extreme temperatures (high and low), moisture and chemicals
- The ability to withstand thermal cycling and vibration
- Availability in various viscosities
- Room temperature and heat cures
- Moduli ranging from flexible to rigid
In addition, some thermally conductive products serve as electrical insulators, essential for bonding and potting electronic parts. For applications requiring both electrical and thermal conductivity, specially formulated adhesives are available. Certain grades even comply with NASA's low outgassing specifications, standards for flame retardancy and high amp arc ignition resistance, Telcordia 85° C/85% humidity testing, for example.
Enhancing thermal conductivity in polymeric materials
In their natural state, polymeric materials exhibit low thermal conductivity. For example, unfilled epoxy has a thermal conductivity of around 0.15 to 0.25 W/m/K, compared to aluminum's 200 W/m/K. To enhance this property, formulators incorporate ceramic, metallic or nano fillers into the adhesives, increasing thermal conductivity by a factor of 10 or more.
These modified products, while not as conductive as metals, effectively manage heat by eliminating thermally insulating air gaps between heat transfer surfaces.
Thermal conductivity range in Master Bond products
Master Bond's thermally conductive adhesives typically offer thermal conductivity values up to 16 W/m/K, making them ideal for many specialty electronics applications.
For specialized needs, Master Bond continually researches ways to develop systems with higher thermal conductivity without compromising mechanical performance.
Balancing thermal conductivity and bond strength
In certain formulations, there might be a tradeoff between achieving the highest thermal conductivity values and maintaining adequate bond strength. In scenarios where adhesives must perform both structural and thermal management roles, engineers must carefully evaluate and address this trade-off.
By understanding and leveraging the unique properties of thermally conductive adhesives and potting compounds, engineers can design efficient, reliable thermal management systems tailored to specific application demands.