Fantastic Functionality and Where to Find It
While color is important, it’s not the only thing a coating can offer.
Coatings are so often chosen simply for their color—“We need this specific look” or “I want a textured feel” and then coating is chosen in a particular chemistry because it has certain performance properties. Color, texture, sparkle, appearance—they’re all important on a product. Along with form, it’s the first thing we see. While color is important, it’s not the only thing a coating can offer, and believe it or not, great aesthetics with fantastic functionality are not mutually exclusive. Many different types of powder coatings can be formulated to deliver additional functionality and performance while still being available in that specific color. Making the product work for your needs is what it’s all about and there are some gorgeous looking powders with high performance and cutting edge technology built into them.
Inhibiting the growth of microbes
Anti-microbial powder coating solutions use silver ions to help inhibit the growth of microbes on the powder coated surface. With anti-microbial coatings color really isn’t an issue, whether it’s clinical white, nursery pink or pharmacy green, anti-microbial technology is a simple addition. Interestingly, silver ions are environmentally sustainable and silver has been shown to offer protection without high toxicity to humans or animals. The science behind it is pretty simple; when moisture is present, the anti-microbial coating releases silver ions that can attach themselves to a microbe’s cellular enzyme which inhibits the growth of microbes. They will also retain their anti-microbial properties over time and so are used on an extremely wide variety of interior applications.
Powder coatings have developed a well-deserved reputation for being a single coat protective coating, especially over aluminum. However sometimes the substrate, the application or the end use require additional protection; enter the powder primer. Powder coating primers, used beneath a powder or even a liquid top coat, are designed to bring additional protective properties to the substrate. Usually formulated around epoxy resins, the primers are applied to properly pretreated metal and, depending on the formulation, will bring a range of benefits. For example, epoxy primers provide great corrosion protection, can be used with any exterior topcoat and can be modified to be outgassing forgiving for parts where outgassing is a problem. Chip resistant primers will deliver excellent chip resistance and corrosion protection, and conductive primers are designed to provide surface resistance in the static dissipative range (103 to 106 ohms at 100v) as well as excellent film quality, levelling, flow and good chemical resistance. Die-electric primer is specially formulated for electrical insulation applications and exhibits dielectric insulator properties, and zinc rich primer contains zinc for excellent corrosion protection and superior long term exterior performance when used beneath a suitable exterior grade top coat.
Turn up the heat
Heat resistant powders work hard to withstand elevated temperatures without losing gloss, discoloring, cracking, or losing adhesion. The high energy silicon-oxygen bond found in heat resistant silicone resins are essential to a heat resistant powder and ensure the coatings remain stable at elevated temperatures, even in the presence of oxygen in the air. These clever resins ensure that when exposed to elevated temperatures, the powder will continue to adhere, will not crack or delaminate, and will maintain color and gloss.
Once formulated, the coating performance is verified by testing each coating in a high temperature furnace. The actual temperature and dwell time depends on the application and the heat resistance requirement. As well as heat resistance, these powder coatings can also deliver excellent weathering, adhesion and resistance to cracking and delamination, great color retention (especially black, metallics, and dark colors), long term gloss retention and corrosion protection. Understandably they really are the hot new thing.
Removing unwanted graffiti
Powder coatings are often used on interior and exterior applications where a hard, tough coating is a necessity. In many cases, some of these applications are also highly susceptible to graffiti, and not the desirable kind. Removing unwanted graffiti is clearly challenging, time consuming and expensive and anti-graffiti powder coating helps make the removal process a little easier, using common solvents. Clearly great chemical and stain resistance and good durability are important features of many coatings, and building additional anti-graffiti properties into the paint can be a great advantage.
Keeping it clear
We all know about the thousands of colors that powder coatings are available in, but did you know powders are also available as hard working clear coats? They will supply an additional layer of protection either direct to metal or on top of another powder coat and so allow the color or the substrate beneath to show through. Clear coat technology is available in many different chemistries, including TGIC and TGIC free polyester and super durable polyesters, urethanes, hybrids and even fluoropolymers. Powder clears can also be formulated to be used in a high chemical resistant environment, they can be anti-microbial, will pass ISO22196 and JIS Z 2801, and certain clears meet and exceed the BHMA performance requirements. Anti-graffiti clear coat powders will ensure the easy removal of graffiti and other formulations will offer fingerprint protection to high touch or high use products. Powder clear coats are most definitely a case of “more than meets the eye.”
Low cure capability
Powder coatings have long been recognized as the environmentally responsible choice, providing beautiful colors, tough protection and an impressive environmental resume. Powder coatings have no solvents, which means no or very low VOCs; contain no toxic compounds; can be reclaimed, reused or recycled; and do not create toxic waste in the application process. While those in the powder coating industry don’t blink at the fact that countless powder solutions come in a single coat, which means less product and less energy is used in the application process, the same cannot be said for many competing coating products. For those with sustainability objectives—be it you or your customer—powder coatings offer genuine environmental advantages, and many powders can even go one step further. Formulating the powders to have low cure capability means that they either can cure at a lower temperature, or spend less time in the oven. Reducing the oven temperature offers clear advantages in terms of reduction in energy usage, and increasing throughput also helps reduce both the time in the oven and therefore the energy usage per piece. It’s certainly worth asking if the powder you use is available in a low cure formulation, and don’t forget to promote the environmental advantages that powder brings to your product!
And finally, electrostatic dissipative coatings, or ESD coatings are designed for interior applications where electrostatic discharge properties are required. These clever coatings are also available as a polyester powder coating and will offer a surface resistivity of 106 to 10¹¹ Ohms as well as excellent hardness, adhesion and impact resistance. Admittedly, it’s not something you automatically think of when powder coating springs to mind, but these formulations are designed around very specific needs and have proved incredibly successful.
Whether it’s improved scratch resistance, UL or PACAAR approved coatings, powders that offer high reflectivity or even two coat systems that don’t require a bake cycle between them, the list of powder coating capabilities is endless. Simply put, it’s not just paint. These are clever, well designed, highly engineered coatings that PhD chemists with years of experience create to meet the needs of the customer. Is color important? Absolutely, and the thousands of colors matched and created every week give testament to just how important that is. But as designers and professional coaters, knowing the functionality that can be built into that beautiful color is just as important. That old adage rings true, even in the coating world—it’s not just what’s on the outside that’s important, but what’s on the inside too.