Low dielectric constant and low shrinkage epoxy system for power electronics applications

Power electronics is a fast growing field encompassing a wide variety of applications that make use of electronic circuitry for the conversion of energy. In such applications, the electronic circuits must operate with exceptional reliability in severe environmental conditions and many times under conditions of high dielectric stress. Formulated systems based on epoxy resins are used extensively in electronic as well as electrical applications as either potting and encapsulating systems or as casting products. This paper describes a new epoxy system that has been formulated in combination with specially selected inorganic fillers. It is designed for exceptionally low shrinkage and very low dielectric constant making it ideally suited for these power electronic applications. Although the system will cure at room ambient temperatures, a short elevated temperature post-cure provides the optimum properties. Having a low viscosity, it is easily processed at room temperature with good working life.