There is a high demand for thermoplastic conductive coating among the manufacturers of electronic equipment and devices. This coating needs to provide the same level of EMI shielding performance as electroless plating, but it should be devoid of any environmental, safety, and cost issues commonly found in the plating process. To satisfy this growing demand, epoxy coatings have become a popular choice. In this blog, we will discuss why epoxy coatings have become one of the most effective new techniques in the field of EMI shielding.
Characteristics of Epoxy Coating
The highly conductive coatings can easily bridge the gap between performance properties and EMI shielding effectiveness commonly seen in regular high-density coatings.
- Composition: They are made up of a combination of curative, conductive fillers, and epoxy resin.
- Structure: They self-assemble into a unique conductive yet polymeric structure at the time of curing.
- EMI Shielding Capabilities: Epoxy coatings provide very high EMI shielding levels. Some can even ensure shielding of 85+ dB at a thickness of 25 micron across a broad frequency range.
- Additional Properties: Owing to the polymeric nature of the coatings, the level of flexibility and adhesion is quite high. Moreover, they are resistant to humidity, salty environments, and high temperatures – all conditions that electronic applications often encounter.
Why Are Epoxy Coatings Better Than the Traditional Alternatives?
Traditional coatings with the same thickness and density as epoxy coatings are not capable of delivering EMI shielding more than 85 dB. Moreover, epoxy coatings are lightweight, which is very useful when integrating an EMI solution to an application. These two reasons coupled with cost considerations are the primary reasons why manufacturers hesitate to apply thicker coatings.
Epoxy coatings are quite adaptive, and their unique base chemistry means they can be converted into different products, such as sprays, adhesives, and films.
In spray format, they can be applied manually without any hassle or using automated equipment. Handling this spray is like handling paint, which means that you can use a low-pressure, high-volume spray gun to easily apply it onto complicated thermoplastic shapes. If you want an enhanced control over the thickness level while spraying across a part, you can apply the coating using robotic systems. The best part is that epoxy sprays, when kept at room temperature, have indefinite shelf life.
Thanks to the inherent structure of epoxy coating, it enjoys a high stability at room temperature. This unique quality makes it useful for being converted into a liquid-dispensable adhesive. In this form, an epoxy coating combines the benefits of being used as a traditional adhesive and functioning as an EMI shielding agent.
Epoxy films can easily be sheeted in big pieces for large scale applications. This form finds a huge application in the aerospace industry as it can be easily applied to larger sections of the aircraft at the time of assembly. This protects the aircraft from both lightning strikes and EMI.
Thanks to epoxy coatings, manufacturers in the industry finally have a highly conductive material that is mainly a polymer but behaves much like metal. Since they can be used across a wide frequency range, these coatings have industry-wide applications and usually yield over 50 percent cost savings compared to the electroless plating of plastics as well as other high-performance acrylic systems.
Manufacturers have begun to look for lightweight materials to use in their designs, and epoxy coatings fit the bill perfectly. They provide a good level of EMI shielding at low prices. As they meet industry expectations, they have become the standard.