Potting Compounds That Beat The Heat
October 6, 2014
October 3, 2014 - How do I get the heat out? This thermal management question is particularly difficult to answer when it involves potted or encapsulated electronics.
Potting compounds do a great job at shielding delicate electronics from moisture, chemicals, shock loads, vibration and other damaging operating conditions. Yet conventional potting compounds can hinder heat dissipation—because the compounds’ base polymers act as thermal insulators.
Fortunately, there are a number of additives and fillers that can transform thermally insulating base polymers into thermally conductive potting compounds with conductivities on the order of 2 W/m•K. These conductive products typically incorporate blends of inorganic fillers such as alumina or silica. They may also require subtle changes to the potting compound’s base resin so that conductivity doesn’t come at the expense of flow or other desirable physical properties.
When properly formulated by an experienced supplier, thermally conductive potting compounds can be very close to a drop-in replacement for non-conductive products. Still, there are some important details to keep in mind when specifying thermally conductive products.
These specification details mainly relate to the compound’s base resin. Epoxy, silicone and urethane are the three primary chemistries for thermally conductive materials, and each one has advantages in different applications. Here’s an overview:
- Offer the best chemical resistance of the three chemistries.
- Provide extremely high adhesion, so they excel in robust products that will not need future repairs.
- Resist moisture contamination in the uncured state, making them a good fit in assembly operations with potential moisture exposures.
- Offer the best high temperature performance of the three choices.
- Have low adhesion values, which can be an advantage in products that may need rework or repair.
- Exhibit low hardnesses, which can be desirable in applications requiring shock resistance.
- Are inherently flame retardant.
- Perform well at low temperatures.
- Offer good toughness for applications requiring shock load resistance.
- Are hydrolytically stable, making them a good choice for products that will be exposed to the weather.
Epoxies, Etc. formulates a variety of thermally conductive potting compounds in each of these chemistries. Our most popular products include:
- 50-3152FR–Flame Retardant Thermally Conductive Epoxy, UL94-V0 Listed
- 50-1225–Thermally Conductive Silicone Rubber
- 50-2369FR–Flame Retardant Thermally Conductive Polyurethane, UL94-V0 Listed.
Request a sample of these products or other thermally conductive potting compounds today.