Dow DOWSIL CC-8030 UV and Moisture Dual Cure Conformal Coating

Dow has introduced the DOWSIL CC-8030 UV and Moisture Dual Cure Conformal Coating — a solventless silicone conformal coating with an ultraviolet (UV) and moisture dual cure system for high throughputs. The silicone technology is designed to promote sustainability, health and safety while reducing processing costs through automated spraying and fast, energy-efficient UV curing. Other silicones support UV curing, but none are conformal coatings with a low enough viscosity for spray coating and with a secondary moisture cure for shadowed areas, according to the company.

The product is an environmentally progressive solution for protecting rigid PCBs, sensitive electronic components and fine-pitch designs from environments with airborne contaminants. The silicone conformal coating is formulated without benzene, toluene, ethylbenzene or xylene (BTEX) solvents. It also has a low modulus for delicate components and high elongation for protection against stress. To provide a greater level of PCB protection, the coating can be applied in multiple layers. It also provides good protection against thermal cycling, particularly compared to acrylated urethane UV cure coatings.

A soft, medium-viscosity silicone, the conformal coating has a rheology that is designed for high-throughput spray coating. Its dual cure technology combines speed with completeness of coverage for reduced work-in-process inventory. With UV curing from a standard mercury broad spectrum lamp at 300 mW/cm², the coating is tack-free after less than 10 s. Compared to thermal ovens that cure in minutes, UV ovens are also smaller and consume less energy. Further, the coating’s secondary alkoxy moisture curing reaches any shadowed areas where UV light can’t penetrate, or UV curing is otherwise incomplete. Moisture curing also supports thicker coating and won’t add stress from thermal cycling.