Many components and printed circuit board locations must remain uncoated and the purpose of the conformal coating masking tapes are to prevent migration of the conformal coatings into these critical areas. These tapes offer the high temperature resistance needed in the conformal coating process.
The objective of conformal coating is to apply a protective layer to the printed circuit board. This prevents degradation of electrical performance when subjected to environmental stresses encountered under operating conditions. Humidity is the most prevalent issue and the most damaging environmental stress as it can drastically lower insulation resistance between conductors, accelerate high-voltage breakdown and corrode conductors. Conformal coatings also protect the printed circuit board and components from airborne or solvent borne contaminants.