Protective coatings are used to enhance the performance and reliability of printed circuit board assemblies for use in harsh environments such as underwater, aerospace and military applications. Manufacturers of consumer electronics products are increasingly using contouring coatings as an economical way to improve the reliability of their products.
When a printed circuit assembly board without a protective coating is exposed to moist air, a thick film of water molecules forms on its surface, reducing the surface insulation resistance (SIR) of the circuit board. The lower the surface insulation resistance, the worse the transmission performance of electrical signals will deteriorate. The typical consequence is cross-talk, electrical leakage and transmission discontinuities, which may lead to permanent interruption of signals, i.e. short circuit.