Why is Epoxy Used for Surface Coating?

From protecting pipelines to sealing warehouse floors, an epoxy surface coating protects surfaces strengthens materials, and protects them from corrosion and decay, making epoxy one of the most widely used industrial finishes. While epoxy coatings may initially cost more than other types of surface coating materials, its ability to provide superior and durable corrosion resistance, adhesion, and flexibility to a variety of surfaces ultimately make it a more economical choice, as the need to reapply the coating may be less frequent when materials are prepared well.

Types of Epoxy Surface Coating

There are a variety of applications for epoxy-based materials on the market, including coatings, adhesives, and the creation of composite materials. Those used for surface coatings are known for their good mechanical properties, electrical insulating properties, adhesion, and chemical- and heat resistance.

The most common types of epoxy resins include bisphenol A, bisphenol F, and phenolic novolac. Hardeners, or co-reactors, used with epoxy resins include polyamide, amidoamine, phenalkamine, aliphatic amine adducts, cycloaliphatic amine, aromatic amine, an aliphatic amine. The best resin and co-reactant combination depend on the purpose of the application and the performance requirements sought. If you seek a coating with high chemical and corrosion resistance, for instance, you may use a phenolic novolac resin with a polyamide co-reactant.

Epoxy Surface Coating Considerations

Epoxy coatings require specific environmental conditions to ensure the success of their application, as well as the proper preparation of the respective surfaces. When applying an epoxy coating to steel, for instance, you may need to remove the thin corrosion layer that naturally forms on the surface. Methods of cleaning surfaces include the use of chemicals or blasting products.

After you prepare and clean a surface, it becomes vulnerable to environmental contamination. When working with steel, for example, it takes as little as 30 minutes for flash rust to form. The longer you wait to apply an epoxy surface coating, the shorter the expected field longevity becomes. For this reason, manufacturers provide specific instructions regarding how quickly to apply the first coating and the ideal environmental conditions.

In general, epoxy manufactures recommend the following conditions:

• Temperature: Above 55° F, or at least 5° F above the dew point, for the first 72 hours of drying; some coatings require thermal cures using high heat
• Relative humidity levels: 85 percent or less
• Air: The area should have air circulating over the surface as it dries
• Induction time: It is critical to allow the freshly mixed material to stand for the recommended amount of time, especially in humid or cold conditions
• Pot life: The amount of time the coating material remains suitable for use after mixing the resin and hardener; if you exceed the pot life, the coating may look usable but will perform poorly

The success of a protective epoxy coating depends on the surface’s cleaning and preparation, as well as the ambient conditions to which the surface is exposed during the preparation, application, and curing periods. When a controlled environment, such as a factory, isn’t available, professionals look to temporary climate control solutions to create the ideal ambient conditions for every step of the epoxy surface coating process. From shipyards to power plants to construction sites, Polygon’s custom temporary climate control technologies give you the ultimate control over ambient conditions, so your project is no longer at the mercy of the weather or HVAC systems. Contact Polygon to learn more about how its climate control solutions will enhance epoxy surface coatings and keep your project on schedule and within budget.