Chemtronics - Conformal Coatings Guide

Our thanks to Chemtronics for allowing us to reprint the following article.

 

Overview

 

Conformal coatings are specialty film forming products that protect circuit boards and other electronic components from adverse environmental conditions. These coatings ‘conform’ to the irregular landscape of the circuit board, providing increased dielectric resistance, operational integrity, and protection from corrosive elements, moisture, heat, fungus, and airborne contaminants such as dirt and dust. With continued miniaturization of electronics, the necessity of conformal coating has increased because the additional insulative coating layer between circuits can prevent arcing or current bleed.

 

Conformal Coating Resin Types

 

Conformal coatings can be classified in five main categories:

AR – Acrylic Resin
SR – Silicone Resin
UR – Polyurethane (Urethane) Resin
ER – Epoxy Resin
XY – Parylene

 

These categories are based on the basic resin of each coating. The chemistry determines the major attributes and functions of the conformal coating. Choosing the proper conformal coating for your application is determined by operational requirements of the electronics.

 

AR – Acrylic conformal coatings provide fair elasticity and general protection. As one‐part systems, they are easy to apply and remove. Acrylic conformal coatings are recognized for their high dielectric strength, abrasion resistance and ease of removal.

 

SR – Silicone conformal coatings provide excellent protection in a very wide temperature range. They provide good chemical resistance, salt spray resistance and are very flexible. Removal can be challenging...



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