Because of their impressive durability and environmental advantages such as an absence of solvents that emit VOCs, powder coatings have been a go-to option for industrial applications for decades.
While early generations of powder coatings offered application ease and one-coat protection, they also produced slightly rough, textured surfaces. Since then, advancements in resin chemistry, application and curing have not only elevated their sustainability and performance advantages, but also the aesthetics of powder coatings.
Powder coating pioneers like PPG have invested heavily in research and development to develop newer formulations that combine all the advantages of powder technology with finishes that offer the smoothness, glossiness and color richness of liquid coatings. Thanks to these efforts, we are now closer than ever.
About Gloss
Historically, liquid coatings were favored for their ability to create higher gloss finishes, but that is slowly changing.
Innovations in powder technologies over the years include formulations with extended gloss ranges, from low gloss and matte finishes to reflective mirror-like looks.
While we tend to think of gloss in terms of low, medium and high, sheen is actually quantifiable using a glossmeter that calculates the intensity of reflected light of a liquid or powder coating. The meter directs light at the surface at a fixed angle, typically 20° for high gloss; 60° for semi-gloss; and 85° for low or matte surfaces. The light is reflected back to the meter where it is measured and valued in Gloss Units, commonly referred to as GUs.
- Low gloss matte finishes range from 5-10 GU.
- Semi-glosses fall around 30-50 GU.
- High-gloss surfaces are greater than 70 GU,
Generally, most coatings fall within 0-100, although surfaces like mirrors can have gloss units of up to 2000.
Today’s powder coatings offer increasingly higher gloss levels, even chrome-like finishes created with sparkling mica and metallic pigments. This allows applicators and manufacturers to create liquid-like looks with the practical and performance benefits of powder coating technology.
Applications on automotives and motorcycles illustrate the ability of powders to create highly reflective finishes in the 90 to 95 range that are reminiscent of sheets of glass.
High gloss, reflective finishes in architectural applications offer contemporary looks that are growing in popularity. These coatings for exterior building components like window frames and curtain walls not only add visual appeal, but they are engineered to withstand the effects of weathering, including chalking and fading. Their sheen often makes them more resistant to staining and dirt, which helps to reduce long-term maintenance needs.
As a pioneer in architectural metal coatings, PPG announced the launch of patent-pending PPG CORAFLON® PLATINUM powder coating in 2021. Compared to standard FEVE powders, this patent-pending formulation offers higher transfer efficiency and improved one-coat corrosion protection, as well as an extended gloss range of 5 to 85 compared to 25 to 70. This industry breakthrough gives architects and specifiers an ultra-durable formulation that meets rigorous FGIA/AAMA 2605 performance specifications with the ability to create higher glosses than previously possible with the technology.
Smoothness & Color Clarity
What makes achieving liquid-like looks more challenging with powders is its chemistry. Liquid coatings use solvents that separate the film and pigments during drying and 
curing, which accentuates color richness, gloss and depth. The even flow of liquid coatings helps to ensure consistent film thickness that covers irregularities and optimizes the gloss effect by creating a smoother, more reflective surface.
While powder coatings often use leveling agents that minimize surface defects and wetting properties to achieve smoothness, they are 100% solids that lack the movement of liquid materials in the film during the curing process.
But there are ways to heighten the color intensity and richness of powder coatings. One of the advantages of powder coating is that it can be—and often is—a one-coat process. However, layering of multiple coats not only elevates protective performance, but can create liquid-like color with vibrancy, clarity and depth.
To enhance the color aesthetics of powder, applicators often start with a light-colored or white basecoat for vibrancy, followed by a color layer that can include additives like mica or metallic special effect pigments. This is often followed by a clearcoat for added gloss, depth of color and a finish that resembles the wet look that liquid coatings provide.
Extra Care in Application
There is no doubt that glossy powder finishes are desirable across a wide range of products like appliances and metal furniture. But application can be more challenging so careful attention to details is warranted. Applicators need to thoroughly clean the surface to remove even the smallest contaminants that can lead to imperfections in the finish, closely follow curing procedures with strict adherence to coating manufactures guidelines and conduct periodic checks with a glossmeter to ensure that the desired sheen and smoothness standards are being met. The support of a technical team with expertise in powder coating application can help troubleshoot and provide on-site support to ensure that the desired finish is achieved.
Sustainability at the Forefront
When it comes to creating glossy sheens with rich colors, solvents play an important role in liquid coating technologies. However, solvents are increasingly under scrutiny because they release volatile organic compounds (VOCs) into the atmosphere during the drying process, which contributes to the formation of ground-level ozone. Government agencies around the world are focused on reducing these emissions.
In fact, interest in industrial coatings that are made without solvents is a primary factor behind the growing use of powder coating technologies. Additionally, while liquid coating application is a spray to waste process, powder overspray can be reclaimed and recycled and there is no wastewater to manage in the powder coating process.
New powder formulations offer a host of valuable benefits, including sustainability advantages, contemporary looks that are getting closer to liquid-like finishes, plus durability that resists chipping, abrasions and the effects of weathering.
Land the Look, Achieve the Performance
Super glossy smooth finishes have an inherent appeal that transcends industries and innovations in powder coatings are helping to shape a wide range of products. Whether for automotive finishes, consumer electronics or architectural coatings, the shine adds sophistication and modernity to a variety of substrates. By achieving smoothness, high gloss and color depth with powder coatings, manufacturers can get the best of both chemistries—the desirable looks of a liquid and the sustainability advantages of a powder coating.
PPG is a leading supplier of powder coatings to the automotive, general industrial, appliance, furniture and other key industries. It has an expansive global footprint with 21 powder manufacturing plants – seven with bonding capabilities – a powder resin plant, an R&D development center and a global center of excellence.
Powder coatings play a key role in PPG’s ongoing efforts to lower its carbon footprint, reduce water, energy and waste, utilize more renewable energy sources and achieve 50% of sales from sustainably advantaged products by 2030.
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