About 75% of the North American coil coating industry is dedicated to building products. Since the lifetime of these products is measured in decades, as opposed to merely years, the weathering performance of the coatings used for this market is critical. Understanding how coatings perform, therefore, is essential. There are many approaches to studying weathering performance, and one of the more interesting techniques to accelerate the weathering process involves the devices described in these two ASTM standards:
As an association, the National Coil Coating Association (NCCA) has the ability to speak with one voice on any number of issues. The association is dedicated to the coil coating process: cleaning a metal substrate (aluminum, hot-dipped galvanized steel, etc.), chemically treating the substrate to enhance corrosion resistance and paint adhesion, priming the strip with a corrosion-resistant primer, and topcoating the strip with any number of materials designed to provide aesthetics and durability to the coil-coated metals used in the construction products, transportation, appliance, and HVAC markets. Continue reading
It goes by many names: prepainted metal, coil coated metal, prefinished metal. Each of these descriptions refers to the product of a coil coating line, sometimes called a continuous coil line (CCL). Prepainted metal is commonly used as a coated product in construction applications (metal walls and roofs are two examples), as well as appliances, HVAC units (air conditioners, furnaces, etc.), rainware products (gutters, downspouts, flashing, etc.), and many others. Prepainted metal is the product; a CCL is the application process used to produce prepainted metal.
In Part One, we discussed The Hidden Strength of a prepainted metal system (the base metal, the metallic layer, the pretreatment and primer). In Part Two, we examined The Visible Beauty of prepainted metal: color, gloss, texture. Strength and beauty—not to mention durability and sustainability—are important features, but the coil-coating industry also offers The Functional Capability that sets prepainted metal apart from other products, and most of this functionality can be built into the coil-coated topcoat. This topcoat layer, compared to the base metal, is thin—about 2% to 4% of the total thickness of the prepainted article. But what an incredible layer it is! In addition to providing the aesthetic properties (color, gloss, texture, etc.), coil-coating topcoats can be formulated to provide many functional properties. Continue reading
In Part One, we discussed The Hidden Strength of prepainted metal. It’s easy to take for granted all that lies beneath the surface of prepainted metal: the cleaning and pretreatment of the base metal, the metallic coating, and the continuous process that prepares the metal strip for primer and topcoat, all in one pass through the coil coating line. Here in Part Two, we’ll learn about the only feature that is actually visible in a prepainted part—the topcoat; that is, The Visible Beauty. There is, however, more to it than meets the eye. Continue reading
Part One (of Three)
When you look at a piece of prepainted metal, what do you see? Certainly a colorful article that may or may not have some shape to it. Often the metal is fabricated with “ribs” to add structural strength to the panel, or it may be flat, as is the case with a metal composite material (MCM) panel. The surface of the prepainted article might be a smooth, homogeneous surface, or it may have a wood-grained pattern, or it might have a subtle pebbly texture. The color of prepainted metal ranges from whites, grays, and blacks to neutral earth tones to saturated, brilliant colors. Some of the colors have metallic or color-shifting effects. But this layer of color is only what you actually see. What you don’t see is all that is under the surface. Continue reading
Several years ago, scientists hypothesized that a narrow spectrum of ultraviolet light called far-UVC could kill microbes without damaging healthy tissue. Far-UVC light at about 222 nanometers (nm) has a very limited range and cannot penetrate through the outer dead-cell layer of human skin or the tear layer in the eye, so it’s not a human health hazard. But because viruses and bacteria are much smaller than human cells, far-UVC light can reach their DNA and kill them. In the study, aerosolized H1N1 virus—a common strain of flu virus—was released into a test chamber and exposed to very low doses of 222nm far-UVC light. A control group of aerosolized virus was not exposed to the UVC light. The far-UVC light efficiently inactivated the flu viruses with about the same efficiency as conventional germicidal UV light. Continue reading