Potting refers to the process of injecting a liquid resin compound into devices containing electronic components and circuits, either manually or mechanically. The resin then cures under normal or heated conditions to form a high-performance thermosetting polymer insulating material. The liquid resin compound used in this process is called potting compound. Electronic thermal conductive potting compounds are primarily used for bonding, sealing, potting, and coating to protect electronic components. Before curing, potting compounds are in a liquid state and have flowability, with their viscosity varying based on the product material, performance, and manufacturing process. Once fully cured, the potting compound achieves its functional value, providing waterproofing, moisture resistance, dustproofing, insulation, thermal conductivity, confidentiality, corrosion resistance, temperature resistance, and shock resistance.
There are many types of electronic thermal conductive potting compounds. The most commonly used and widely available are mainly three types: silicone resin thermal conductive potting compound, epoxy resin thermal conductive potting compound, and polyurethane thermal conductive potting compound. These three types of potting compounds can be further subdivided into hundreds of different products.
Silicone Thermal Conductive Potting Compound
There are many types of silicone potting compounds, and the properties such as temperature resistance, waterproof performance, insulation performance, optical performance, adhesion to different materials, and hardness vary greatly between them. Silicone potting compounds can incorporate functional fillers to impart properties such as conductivity, thermal conductivity, and magnetism. The mechanical strength of silicone potting compounds is generally weak, which is actually beneficial for repairability. If a component fails, the potting compound can be pried open, and the defective component can be replaced while allowing continued use.
The color of silicone potting compounds can generally be adjusted as needed, either transparent, opaque, or white. Silicone potting compounds perform excellently in shock resistance, electrical performance, waterproof performance, high and low-temperature resistance, and aging resistance.
Two-component silicone potting compounds (also called AB compounds) are the most common. These include both condensation and addition types. Condensation-type potting compounds have poor adhesion to components and potting cavities, and they release volatile low-molecular substances during the curing process, which results in a noticeable shrinkage. Addition-type compounds (also known as silicone gels) have minimal shrinkage and do not produce low-molecular substances during curing. They can be rapidly cured with heat.
Advantages: After curing, silicone potting compounds are relatively soft and come in two forms: solid silicone rubber products and silicone gels. They can absorb most mechanical stress and provide shock protection. They have stable physical and chemical properties, excellent high and low-temperature resistance, and can operate within a temperature range of -50 to 200°C for extended periods. They have excellent weather resistance, providing effective protection for over 20 years in outdoor environments without easy yellowing. They also offer superior electrical performance and insulation, effectively improving the insulation between internal components and circuits, enhancing the stability of electronic components. Additionally, they are repairable, making it quick and easy to remove and replace sealed components.
Disadvantages: Adhesion properties are slightly weaker.
Application Range: Ideal for potting various electronic devices that operate in harsh environments, as well as high-end precision/sensitive electronic devices, such as LEDs, displays, photovoltaic materials, diodes, semiconductors, relays, sensors, automotive stabilizers, in-vehicle computers (ECU), etc. The main functions include insulation, moisture resistance, dustproofing, and shock absorption.
