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Conformal coatings rose to prominence in protection of printed circuit boards (PCBs) about five decades ago. Through their use, early PCB failures due to dust and dirt, liquids, and humidity contamination were greatly reduced or eliminated. This in turn allowed for the longer warranties and improved reliability we see today. Early conformal coatings, many of which are still in use today, were comprised of polymers dissolved in various solvents such as MEK, toluene, or xylene.

An approximate evolution of conformal coating chemistries could be viewed as

1. solvent-borne acrylics and polyurethanes
2. waterborne acrylics
3. synthetic rubber coatings
4. UV-curable acrylated urethanes
5. LED UV-curable acrylated urethanes

The evolution of conformal coatings for protection of PCBs and electronics has accelerated over the past few years. One development in particular has increased in popularity due to a promising array of advantages over its predecessors. These are LED Curable Coatings.

A partial list of existing technologies for conformal coatings would include:

• acrylics (both solvent and water-borne)
• solvent-borne polyurethanes
• silicone-based polymers
• synthetic rubber (solvent-borne)
• Parylene technology
• UV-curable acrylated urethanes (arc and microwave bulb source)

and most recently . . .