Encapsulants Review

Encapsulants are chemical compound materials used to completely encase a electrical, electronic or other part or assembly. Encapsulants are normally applied in a liquid state within a special molding container or enclosure. The encapsulant material then cures at ambient temperature or is subjected to a specified elevated temperature to hasten curing or solidification. Some encapsulant technologies facilitate curing by the application of UV light. Some of these compounds cure within seconds on the UV light application. Encapsulants may also be referred to as potting compounds.

Encapsulants are available in rigid and flexible compounds. Most often, encapsulants are used to encase and isolate electronic circuit boards and assemblies from the operation environment preventing harmful interactions of moisture, provide electrical insulation, and protect the part or assembly and interconnections from thermal and mechanical stresses. Encapsulants are also used to reinforce electrical connectors, preserve biological specimens, and package curios. Most encapsulates are epoxy based compounds, however polyurethane, silicone and other polymer based compounds are also employed.

Engineering and design considerations for encapsulants are: dielectric strength, thermal, mechanical, vibration, rigidity, flexibility, time for processing, material compatibility, out-gassing, resistivity and coefficient of expansion. Other consideration are encapsulant viscosity, application temperature, handling and storage, curing temperature, curing time requirements, post cure requirements, standards compliance, and maximum handling time or pot duration.