Epoxy Powder Coating – Applications, Benefits and More

Powder coating is a type of coating that is applied as a free-flowing, dry powder. The main difference between liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electro-statically and is then cured under heat. Epoxy powder coating is a good choice for coating most types of metals and electrical parts.

Powder Coating Applications
Over the years, advances in the application methods and powder chemistries have expanded the use of epoxy powder coating within the electrical field. Common applications now include motor components, switchgear and cable replacement, to name a few. Many powders used for these types of electrical insulation applications are rated as class B service coating and have a UL 94 V-0 flammability rating. The dielectric strength in certain powder formulations can consistently achieve 800v/mil based on the appropriate surface preparation, application method and component geometry.

Powder Coating Advantages
There are several advantages of powder coating over conventional liquid coatings:
1. Powder coatings emit zero or near zero volatile organic compounds (VOC).
2. Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
3. Powder coating overspray can be recycled and thus it is possible to achieve nearly 100% use of the coating.
4. Powder coating production lines produce less hazardous waste than conventional liquid coatings.

Types of Powder Coatings
There are two main categories of powder coatings: thermosets and thermoplastics. The thermosetting variety incorporates a cross-linker into the formulation. When the powder is baked, it reacts with other chemical groups in the powder to polymerize, improving the performance properties. The thermoplastic variety does not undergo any additional reactions during the baking process but rather only flows out into the final coating. The most common polymers used are polyester, polyurethane, polyester-epoxy, epoxy and acrylics.

Powder Coating Preparation
The surface requires a thorough cleaning and drying prior to the powder application. All contaminants must be removed to ensure proper adhesion. A phosphate solution and rinse is commonly used. There are a number of ways this can be accomplished, including spray wand applications, immersion systems or recirculating spray washers followed by a complete drying cycle.


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