Powder coating is a versatile technology used in various automotive, architecture, and aerospace industries that use wood, metal, and plastic materials.
Powder Coating Explained
Powder coating is a surface finishing technique in which dry, free-flowing powder is sprayed on a surface, melted, and hardened to form an even coating. Powder coatings can be used on wood, metal, glass, and non-metallic materials such as plastics and medium-density fiberboard (MDF). They form an even and decorative surface coating in various colors, textures, and finishes that are unattainable with liquid coating methods.
Powder coatings comprise polymer resin systems, pigments, flow modifiers, curatives, leveling agents, and other additives. The components are then melted, mixed, cooled, and ground into a smooth powder. The powder is subsequently applied to the substrate using electrostatic spray deposition (ESD), employing a spray gun as the powder coating equipment, where the powder particles are charged electrostatically and adhere to the grounded part. Once the powder coating is applied, the sprayed parts are placed in a high-temperature curing oven. The coating chemically reacts to form long molecular chains, forming a high cross-link density.
In certain instances, a fluidized bed application method is used for powder coating, where preheated parts are immersed in a container of fluidizing powder. The powder melts, flows onto the surface of the part, and post-curing may be necessary depending on factors like part mass, temperature, and powder type. Despite the application process, powder coatings are user-friendly, environmentally friendly, cost-effective, and long-lasting.
Types of Powder Coatings
Powder coating can be categorized into two types: thermoplastic and thermoset. These two vary in terms of their curing methods and properties.
Thermoplastic Powder Coatings
Thermoplastic is a coating that melts and flows when heated but maintains the same chemical composition once it solidifies. As a result, it has better resistance to impacts on the finished product.
Also, it doesn’t need a curing cycle. Instead, the coating necessitates sufficient time and elevated temperatures to achieve a uniform melting and flowing process across the entire surface. Due to the absence of a curing process, thermoplastic coatings have the ability to soften and melt again when exposed to high temperatures. Although thermoplastic coatings may require a thicker application and may not provide the same visual appearance as thermoset coatings.
Thermoset Powder Coatings
Unlike thermoplastic coatings, thermoset powder coatings undergo a curing cycle, resulting in an irreversible chemical change that creates a long-lasting, hardened coating. Although thermoset coatings still melt and flow upon being heated, they chemically bond to create a unique chemical composition from the base resin. As a result, the changes formed after curing are permanent and the coating won’t remelt when exposed to high temperatures.
Thermoset powder coatings have a better scratch resistance than thermoplastics. While thermoset powder coatings create visually appealing, thinner films compared to certain thermoplastics, they are prone to brittleness and cracking when applied in thicker layers.
Advantages of Powder Coating
Powder coatings offer many benefits to the finished products and industries. These include:
- Diversity: Powder coating can achieve a wide range of finishes quickly.
- Durability: The powder coatings have thick layers that protect against corrosion, scratches/chipping, and fading. They can also produce much thicker coatings than conventional liquid coatings without running or sagging.
- Save on costs: Powder coating is preferred to liquid paint because it is more economical, long-lasting, and offers the most color-durable quality finishes available on any material. It also achieves a consistent color finish across the finished product.
- Eco-friendly: Powder coatings are non-toxic and less flammable than liquid spray paint finishes.
Get High Quality and Durable Powder Coating Services
Powder coating is a conventional, safe, and cost-effective technique for forming finished product coatings. At PSI Industries Inc., we can help you choose the powder coating that best suits your needs. Our ISO 9001: 2015 certification is a testament to our high-quality and durable powder coatings and coating services.
Contact us today to request a quote.