Comparison of the characteristics of PCB protective coatings

This article presents a research focused on printed circuit board (PCB) protective coatings as an option for cover the assembled PCBs and electronic device reliability improvement. The experiment with five different coatings is described in the article. For the experiment rigid substrate (FR-4) and flexible substrate (Kapton) were used. The protective coatings from acrylic, urethane, silicone and fluoropolymer materials were used. The differences in substrates and coatings has an effect on the insulation resistance which was measured by SIR test. The samples were exposed to accelerated aging tests - combined accelerated aging by temperature and humidity, and salt spray test. The advantages, disadvantages, comparison and results from measurement are discussed in this paper.