Dielectric Epoxy: A High-Performance Insulating Solution
Dielectric epoxy provides an insulating layer between two conductive materials, making it an essential material in applications where electrical insulation is required. In simple terms, it is a type of non-conductive epoxy that does not allow electricity to flow. Dielectric materials are widely used in electronics manufacturing, especially in components such as capacitors and multilayer circuit boards. Dielectric epoxy adhesives are critical in preventing electrical shorts by acting as barriers between conductive layers. Many Epoxyset products offer strong dielectric properties and are designed specifically for use as electrically insulating adhesives. When selecting a dielectric epoxy, reviewing the product’s data sheet for electrical properties is vital.
Volume Resistivity
Volume resistivity measures the resistance of an insulating epoxy when a voltage is applied. It indicates how well a material resists electrical current; the higher the value, the better the insulation. High-performance dielectric epoxies typically have volume resistivity values above 1.0 x 10¹² ohm-cm at 25 °C. In contrast, conductive epoxies have values below 0.001 ohm-cm. Volume resistivity can decrease as temperature increases, so it’s important to know the operating temperature of your application. Above the glass transition temperature (Tg), molecular motion increases, and dielectric performance may diminish.
Dielectric Strength
Dielectric strength, or breakdown voltage, defines the maximum voltage a material can withstand before it fails. It’s expressed in volts per mil of adhesive thickness. A typical recommendation is a minimum bond line thickness of 2 mils, but higher voltages require more insulation. Temperature can also affect dielectric strength due to changes in physical properties, so consider the thermal environment of your assembly when choosing a dielectric adhesive.
Dissipation Factor
The dissipation factor, also referred to as the loss tangent, describes how much electrical energy is lost as heat. In dielectric epoxy adhesives, lower values indicate better insulating performance. Values near 0.03 at 1kHz and 0.05 or lower at 1MHz are considered good benchmarks for electronic-grade insulating epoxy systems.
Dielectric Constant
The dielectric constant is a measure of how much electric charge a material can store. A dielectric adhesive typically falls in the range of 3.5 to 6.0 at 1kHz. This property is also temperature-sensitive. If a cured epoxy is exposed to temperatures above its Tg, the dielectric constant increases, which may reduce its effectiveness as an electrical insulator.
Applications of Dielectric Epoxies
While not always the first property users consider, dielectric performance is crucial in electronic packaging and high-voltage assemblies. Common uses include semiconductor underfill, wafer passivation, glob top encapsulation, coil impregnation, SMD staking, and ferrite bonding. In large electronic components such as transformers, capacitors, and filters, the dielectric properties of the potting compound are vital for safe operation. Epoxyset provides a broad selection of electrically insulating epoxy adhesives and potting compounds designed to meet rigorous application requirements.
Epoxyset has a wide variety of dielectric epoxies used in all the above-mentioned applications. Our one and two component dielectric epoxy adhesives are engineered to meet demanding application needs. Below are links to epoxy adhesives used extensively for their dielectric properties.
EB-403-1LV-T1 – A one-component epoxy with high Tg for reliable insulation at elevated temperatures.
EB-119M – A two-part, low-viscosity, high-temperature dielectric adhesive for coil impregnation and wafer passivation.
EC-1015 – A high-temperature, low-viscosity potting epoxy ideal for capacitors, transformers, and EMI/RFI filters.
EC-1012M – A flame-retardant epoxy potting compound for linear motors and coil insulation, with flexible hardener options.
EB-316M – A versatile, high-strength, 1:1 mix ratio adhesive used in industrial and electronic applications with strong dielectric and mechanical properties.
For more information about Epoxyset dielectric epoxies or assistance in choosing the right product for your application, contact us at +1 (401)-726-4500 or email us at info@epoxyset.com.
