Thermal Management Properties of Epoxy
Across the globe, the use of electronics is expected to continue its growth in 2022. Among the countries seeing the highest increase in electronic use is the United States. As the industry grows, thermal management is becoming even more vital. All those electronics generate excess heat and risk decreased reliability and premature failure without thermal management.
As thermoset polymers, epoxies exist in everyday household applications like floor, countertop and industrial coatings, primers, paints, and adhesives. The word “epoxy” is often used as a catch-all term for any thermoset found in a hardware store. Still, not all "epoxies" are actually epoxies. Epoxies used in thermal management come in various forms, each offering unique capabilities.
For example, epoxies can be one- or two-component (1K or 2K). 2K epoxies have two sides: one resin side and one hardener side. Common for household applications, these epoxies can be cured at room temperature, or heat can be applied to accelerate the curing process and raise the glass transition temperature (Tg). Conversely, 1K epoxies can be pre-mixed but may require frozen storage until you are ready to use them. For higher performance, 1Ks can be heat cured with latent curing agents, often employed to curb the curing process until attaining a certain amount of energy. Some 1K epoxies will also use a cationic UV cure which allows for a faster process.
Advantages and Limitations of Epoxies
Epoxies offer many advantages—along with some limitations. Advantages include:
• A convenient range of cure temperatures
• Few, if any, volatiles formed during curing
• Excellent adhesion
• Low shrinkage, especially in filled epoxies
• Good environmental and chemical resistance
Some of these advantages can lead to limitations. For example, because epoxies have such excellent adhesion, most are not reworkable or repairable. In addition to their superior adhesion, the rigidity of epoxies can produce cracking if the component gets too cold. If the Tg is crossed over as the material cycles thermally, the rigidity can also cause failures in the application. Therefore, selecting the right product for your application is crucial in the success of your overall design.
Epoxy Thermal Management Solutions
There are two primary classifications of epoxy thermal management solutions. The first classification, potting and encapsulation, is used in battery, electric motor, magnetic, and PCB (printed circuit board) applications. This solution transfers heat away from hot electronics and adds structural support. The second classification, coatings, may be used on heat sinks or as conformal coatings on PCBs. Both solutions provide excellent dielectric and environmental protection.
Two other types of thermal management epoxies are adhesives and underfills. Adhesives can be structural, die-attach, or surface-mount. Underfills, used as encapsulants underneath semiconductor packaging, provide an element of structural support and environmental shock protection.
Applications of Epoxy Materials
Epoxies have many applications, including electronics, industrial (appliances or heavy-duty equipment), LEDs, motors, and transportation. We have four primary classification materials in our epoxies: coatings, microelectronics, potting and encapsulation, and structural adhesives.
Our most popular epoxy-based coating is the LORD JMC-700K Dielectric Coating, a heat-cured epoxy that provides superior electrical isolation. Microelectronics products include adhesives, encapsulants, or underfills.
Potting materials can be used in the following applications, as well as many other unique designs:
• Batteries
• Inverters
• Converters
• Inductors
• Motors
Whichever potting application you’re working on, remember that operating at a lower temperature will provide longer life and better functionality to your electronics.
LINK：https://www.lord.com/blog/electronics/thermal-management-properties-of-epoxy
