Benefits of Using Powder Coatings & its Applications
Posted: May 04, 2019
Modern Approach in Powder Coatings
The latest innovation in powder coating technology is opening up new markets because more applications can be achieved. Powder coatings are available in high and low gloss, metal or satin and various colors without limits.
Special effects pigments can create unique and interesting visual effects in powder coatings. They are compatible in almost all resin systems, and are widely available for long-lasting exterior and industrial applications.
How Powder Coating Works
To appreciate the benefits and benefits of powder coating, it is important to first understand how the powder coating works. Unlike conventional wet paint which has suspended color pigments in a liquid, powder coatings work in a completely dry environment. It is an important component in completing special fabrication and coatings carried out through powder coatings.
In fact, water is a deadly enemy for the powder coating because it works through the process of electrostatic spray (ESD) deposition. Free floating dry powder receives a positive electric charge and is sprayed under pressure onto unfinished fabricated metal objects which are grounded with a negative charge. This creates an electrochemical change in which long chain molecules from the powder attach to the metal and overlay it.
Powder bases can be acrylic, polyurethane, polyester, epoxy or a mixture of these products. Electric polarization of positive and negative currents allows the coating to be entirely uniform. There are no runes or sags in the powder coating process, unlike what happens in excess applications with wet painting.
New alternative - Powder coating does not release VOC (Volatile organic compound ) during the curing process. This benefit makes this coating a viable alternative to traditional coatings containing solvents and water.
Efficient - Powder coating is very efficient because the components are 100% solid, and little or no waste is produced. No need for solvent capture systems. If necessary, the spray booth can be installed in a relatively small area. In addition, the liquid manufacturing system can usually be changed easily into a powder system, because the conveyor and preservation can be exchanged. While capital expenditure is needed to replace the liquid delivery system, it often quickly pays for itself through increased efficiency.
Durable - Powder coatings are more resistant to acid rain and ultraviolet rays from the sun than liquid coatings. They are weather resistant, misuse and hard to use everyday, and resistant to scratches. They have been used effectively in products that demand durability, such as architectural building panels and window extrusion, office furniture, outdoor furniture, equipment, children's toys, bicycles, automotive rims, and motorbikes.
Color Variety - Powder coating colors come in a rainbow of selection. Colors are pre-mixed in the powder pigments by the supplier. That’s done in factory settings with computer-controlled mixing ratios. Carefully pre-mixed powders allow for perfect color distribution that’s difficult to achieve with wet paint products. Black and white are the two most popular powder coating color choices. However, every color in the spectrum is available in stock powders and custom color blends.
Environmentally Friendly - Powder coating is exceptionally friendly to the environment. There are no harsh chemicals used in the powder coating process, unlike wet painting and hot plating. Both oil and waterborne paints use harsh chemicals in their solvent bases and pigment additives. Electroplating uses even harsher chemicals to etch metal and make plating stick. Not so with powder coating. There is only dry powder involved and it goes right from the spray gun to the metal surface.
Cost Savings - Because powder coating uses less equipment, takes less application time and consumes fewer raw materials, it’s a less expensive process than alternatives like plating and conventional painting. Powder bases are stable and have indefinite shelf lives. They offer better value and are less expensive to stock. Labor cost to powder coat is also lower due to the simple two-step system used in powder coating.
Special Effect Pigments in Powder Coatings
The use of special effect pigments in powder coatings is also gaining in popularity. Due to its ease of application and safety benefits, as well as its decorative appeal, effect pigments gain more market share than metals in the powder coating industry.
The biggest market for effect pigments is architectural coatings, which consist of panels and aluminum profiles. Metallic gray is the most popular color for this application, and can be achieved by combining a layer of black or gray powder with exterior white pearlescent pigments. Mica-based effect pigments are a cost-effective and more durable alternative to aluminum pigments. Metal pigments require an additional layer of clear resin to increase durability and reduce stains; mica-based effect pigments are not, because they are chemically inert.
While powder coating is the fastest growing finishing process in the coating industry, it is important to understand some of the current limitations. This section outlines the most important technical difficulties associated with using the effect of pigments in powder coating systems so that powder coatings can be prepared to overcome them.
At present, there are two types of application systems: corona and tribo-charging. Both require effect pigments to be bonded so that the application process works most effectively in powder coating systems. The corona application process is most often used. Tribo filling is generally used on very limited bases and is reserved for complicated geometric shapes.
In the corona application, so that the powder layer is moved to the earthed part, it must first pass through an electrostatic field where it receives a negative charge and then attach to the positively earthed part. Although the dryblend mixture of powder coating looks uniform, the effect of mica-based pigments has an inert nature that affects their ability to accept cargo. This parameter is very important for successful powder coating applications.
Because mica-based effect pigments are not easy to carry cargo, they can easily be separated from the rest of the "filled" layer during the path to that section. The difference in yield capability results in a reduction in pearl pigment transfer efficiency. In other words, during spraying, some of the pearls that are not filled apart from the powder on the way to the part and fall into the collection system, which can cause some problems. The most obvious result is an uneven or mottled layer. Uncharged pearls can also be collected at the end of the deflector, piled into large clumps and then spit into the panel. If this happens, the concentration of pearlescent pigments on the panel will fluctuate continuously, so it is not possible to produce a layer that is consistent on the part of daily operations.
Researchers continue to perfect the efficiency of the current application method. For example, powdered pulp used for automotive clearcoat applications looks promising. In this system, powder resins are dispersed in water. The final result, which is achieved by increasing the flow and leveling characteristics of the powder system, resembles the smoothness of the liquid layer.
Qualitron Chemicals the manufacturer and exporters of Phthalocyanine Pigments is an Evolving Firm built with a vision of producing industry standard Pigments.