Powder coating is a dry finishing process that has become extremely popular since its introduction in North America over in the 1960s. From washing machines and clothes dryers to automobiles, handrails, fences and more, countless products are manufactured with a powder-coated surface.
In this article, all you need to know about powder coating will be introduced.
What Is Powder Coating?
Powder Coating is a way to color different surfaces like metal, concrete, steel, and plastic. The way it works is that powder of a certain color is sprayed onto the surface, which holds an electrical charge. The charge causes the powder to adhere to the surface, and it is baked on once the spraying is done. Compared with paint, powder coating is a more advanced approach - it brings improved durability, a reduced environmental impact, and a higher quality appearance.
How Does Powder Coating Work?
When a product is powder coated, it's sprayed with pressurized dry powder that sticks to the product's surface. This application method uses a spray gun, which applies an electrostatic charge to the powder particles, which are then attracted to the grounded part.
After application of the powder coating, the parts enter a curing oven where, with the addition of heat, the coating chemically reacts to produce long molecular chains, resulting in high cross-link density. These molecular chains are very resistant to breakdown. This step is curing. In general, curing is performed at 400 F for approximately 20-30 minutes depending on the part.
Surface preparation/pretreatment is also essential for achieving a successful powder-coating outcome. This normally entails the removal of grease, oil, dirt and other materials via chemical, physical or mechanical methods to clean the surface and promote coating adhesion. Pretreating the workpiece with chemical compounds can enhance the coating's performance, durability and corrosion resistance.
This type of application is the most common method of applying powders. Powder coating can be used to metal substrates such as stainless steel or aluminum, or non-metallic substrates such as plastics and medium density fiberboard.
The Types of Powder Coating
There are two main types of powder coatings, namely, thermoplastics and thermosets.
The thermoplastics variety does not undergo any additional reactions during the baking process, but rather only flows out into the final coating. Thermoplastics pellets soften when heated and become more fluid as additional heat is applied. The curing process is completely reversible as no chemical bonding takes place. This characteristic allows thermoplastics to be remolded and recycled without negatively affecting the material's physical properties. There are multiple thermoplastic resins that offer various performance benefits, but most materials commonly offer high strength, shrink-resistance and easy bendability. Depending on the resin, thermoplastics can serve low-stress applications such as plastics bags or high-stress mechanical parts.
The thermosets variety incorporates a cross-linker into the formulation. The cross-linking process eliminates the risk of the product remelting when heat is applied, making thermosets ideal for high-heat applications such as electronics and appliances. When the powder is baked, it reacts with other chemical groups in the powder polymer and increases the molecular weight and improves the performance properties, so it is impossible to recycle thermoset powder. Besides, thermoset coatings are often the cheaper of the two.
What Is Powder Coating Used For?
Since powder coating was developed by German scientist Dr. Erwin Gemmer in the 1940s, it has been used by any and all industries that use metal, the bottle industry is no exception.
Powder coating become more and more popular these days for insulated stainless steel bottles. There are several advantages of powder coating layer: anti-slip, durable and colorful. As a leading vacuum insulated stainless steel water bottle manufacturer, GiNT has rich experience in powder coating process, and provided a great number of high-quality powder coated bottles.
If you want to know more, just contact us @kira@gint.cc
