Encapsulants

After dispensing, encapsulants are cured at room temperature or by heat, depending on the specific product being used. These encapsulants will cure in thin or thick section and can cure when confined. Encapsulants can be inhibited by certain materials due to the type of catalyst used, resulting in poor or incomplete cure. For more specifics, please refer to the Gels and Encapsulants Processing Tutorial.

For best results, units to be encapsulated or potted should be clean of grease, oil and other surface contaminants. Common cleaners for substrate preparation include Dow Corning’s line of OS Fluids, isopropyl alcohol, toluene and acetone. 

Room Temperature Cure

A room temperature cure process can be used for most of the standard encapsulants. After being mixed and applied, the encapsulant is simply allowed to cure at ambient room conditions. Most products will require several hours to cure or need to be left undisturbed overnight. Room temperature curing processes are more appropriate for low to medium volume production applications. There are a few encapsulants that are designed for rapid room temperature processing.

For standard encapsulants, a separate priming step may be required for good adhesion to the substrate to with stand temperature cycles. Primerless encapsulants are available but require heat to cure. 

Heat Curing

For any of the heat curing encapsulants, heating will accelerate the cure rate. For the Standard Encapsulants, heat acceleration occurs at any temperature above room temperature. For Self-Priming Encapsulants, cure and the development of adhesion are not achieved until the material is heated above 100°C. Higher temperatures will result in faster cure. Limitations on cure speed are generally dependent on the temperatures that the unit and components are able to withstand. Heat curing can be done in a batch or conveyor oven.