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Acrylic Conformal Coating Services for Electronics | Circuitry Series

a coating engineer observing a printed circuit board with an acrylic coating film

Mallory McGuinness | May 14, 2020

Conformal coatings can protect an electronic component from liquids, UV exposure, and corrosivity. The films conform to the surfaces of components, serving as a barrier.

Conformal coating materials include urethane, epoxy, silicone, and Parylene. Each type presents different performance characteristics and application issues. Acrylic (AR) is the most common conformal coating material.

What are Acrylic Conformal Coatings?

Acrylic forms a tough, durable layer that protects from fungus, moisture, and corrosion. Acrylic coating technology is popular due to its ease of application and removal.

Acrylic conformal coatings exhibit the following properties:

  • Low moisture absorption
  • Relatively short drying times
  • Clear protective coating
  • Good electrical and physical properties
  • Continuous Service in temperatures from -65º to 125 ºC

What are the Benefits of Acrylic Coatings?

Acrylic coatings are hard, robust, transparent, and easy to repair. In general, these coatings are more affordable than other types, as well. The films also exhibit good dielectric strength, enhancing the function of a PCB. They provide long-term resistance to weather damage, good abrasion and scratch resistance, and beneficial electrical properties. Acrylics are easy to repair, dissolving in organic solvents such as xylene.

Acrylics give off minimal, if any, heat during the curing process, minimizing damage. The material can also cure in under 30 minutes, supporting rapid production.

Acrylic coating on a PCB

Each conformal coating material has different properties, performance characteristics, and application issues.

Acrylic Conformal Coatings Applications

Acrylic coatings provide excellent fungus resistance and acid/base protection. However, acrylics are most well-known for moisture protection. The films protect PCBs from humidity, rain, salt, water spray, or seawater exposure. The coatings are useful for optical applications, such as LEDs, due to a high light transmittance and refractive index of 1.48.

The Acrylic Conformal Coating Process

There are several ways to apply acrylic conformal coatings: brush, dipping, and spray. Each of these methods entails a quick, easy application. Brush coating is suitable for smaller batches and is a simple, cost-effective application. With this process, a skilled operator brushes acrylic onto one side of a PCB.

Dipping is repeatable and fast, used for larger batches of electrical components. Dipping entails submersion into a tank of liquid acrylic solution, manual or automated.

Spray techniques are also a popular way to apply acrylic coating. Aerosol spray can be automatic for accuracy and quickness or manual, overseen by an operator.

Learn How to Choose the Best Conformal Coating for Your PCB

Why Choose Acrylic to Protect Your Electronic Products?

If your focus is to lower costs and simplify application, acrylic is likely a good choice. Acrylic films dry quickly, reducing manufacturing time. Additionally, the material is easy to remove with solvent.

That said, acrylic does have drawbacks, including poor chemical resistance, and it can be difficult to maintain coating viscosity during application. If your chemical resistance is a requirement for your application environment, acrylic may not be the best choice. Some formulations degrade or discolor after prolonged exposure to humidity or extreme temperatures.

The Big Picture

Numerous industries, including consumer electronics, aerospace, automotive, and medical device, entail exposure to contaminants, corrosives, extreme temperature, friction, and abrasion. Conformal coatings protect components from these variables and therefore, are a good choice to improve the reliability, function, and lifetime of circuit boards and other components, provided that you choose the best type.

Although understanding conformal coating material is a good start, it is necessary to consider many other factors to understand which type is best for your project. These include processes, including rework, removal, cleaning, masking, and inspection. Your decision will also affect cost, repeatability, scalability, and reliability requirements. For more information, read our extensive guide on conformal coating types or reach out to our Applications Engineering team today.

 

Learn More About Coating Processes

…acrylic does have drawbacks, including safety, environmental, and health concerns that must be seriously considered.

Mallory McGuinness

Mallory is an electronics protection evangelist who writes content for HZO. In her free time she is reading non-fiction, and hanging out with her beta fish, King Awesome.

Ryan Moore

Ryan is a 9-year veteran to the world of protecting electronics from harsh environments and a lover of all things technology.

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