(09/28/2011)

A wide variety of potting and encapsulation materials that are ideal for the solar power industry are now available from LORD Corporation. These low-cost epoxy, silicone and urethane polymer systems offer diverse encapsulant application options especially for junction box protection.

Junction boxes, the small plastic boxes mounted on the underside of solar panels, are particularly prone to degradation from extreme environmental conditions. The junction boxes house the solar panel’s electrical wiring, and must be protected from moisture, fire, vibration and extreme temperature fluctuations such as wind, rain and snow.

To protect the internal electrical connections, encapsulating or potting compounds, are used to fill the junction boxes. The LORD encapsulating and potting compounds are flame retardant, offer good adhesion to various surfaces, emit low mechanical stress on the electrical components, and provide reliable thermal conductivity, along with long-lasting capability.

"These products not only cost less but offer the ability to handle demanding applications so crucial to the solar industry," said Thang Nguyen, LORD Key Account Manager. "Any lower costs associated with manufacturing and assembly of solar power systems help make renewable energy more competitive in the marketplace."

Some of the specific products available from LORD for junction box protection include: Circalok 6035 and 6009 epoxies; UR-312 and UR-322 urethanes; and Circalok 6705, SC-309 and SC-320 silicones. The RoHS-compliant compounds have a convenient mix ratio (1-to-1 resin-to-hardener) and offer a fast curing time of approximately one hour.

• Circalok 6035 and 6009 epoxies provide thermal conductivity and fire retardancy along with mechanical protection and structural support. Circalok 6035 is a low-viscosity, room-temperature-curing potting compound. Circalok 6009 is a two-component epoxy resin system with moderate thermal conductivity and low viscosity.
• UR-312 and UR-322 urethanes offer the highest protection against moisture ingress while maintaining low stress on electrical/electronic components. These two-component, room-temperature-curing gels have excellent thermal shock resistance and adhesion to a variety of materials. They are ideal for encapsulating fragile, pressure-sensitive, microelectronic components that would be damaged by more rigid encapsulants during cure or later thermal cycling.
• Circalok 6705, SC-309 and SC-320 silicone encapsulants offer high thermal conductivity, low stress on components and maximum temperature resistance. Circalok 6705 is an addition-cure silicone system that produces no by-products. It has excellent reversion resistance at high temperatures and does not cause corrosion. Both SC-309 and SC-320 are durable, two-component systems composed of an addition-curing polydimethyl siloxane polymer that will not depolymerize when heated in confined spaces.

"SC-309 low-viscosity silicone encapsulant is especially useful for solar applications," noted Nguyen. "It offers a good combination of thermal conductivity and resistance to environmental stress that makes it ideal for junction box protection."