When it comes to effective, reliable industrial coatings, powder is on the rise globally and it’s easy to see why. The technology holds significant performance advantages like advanced corrosion protection, edge coverage, and lower volatile organic compound (VOC) content, the focus of ambitious global efforts to address climate change.
Powder coating uses an electrostatic process that applies electrically charged paint particles to a grounded part. As a result, it has an impressive adherence to metal substrates.
A key factor in powder’s rise is the development of newer high transfer efficient (HTE) powder coatings that elevate coverage by improving first-pass application build rates. The benefits, aside from a greater percentage of product being deposited on the part, are a more efficient method of application and less wasted powder.
Contemporary Powder Improvements & Techniques
PPG’s lab-born HTE powders deposit powder with high consistency and uniformity, even on complex parts. Being specially formulated to electrostatically wrap and penetrate into deep recesses or hard-to-reach surfaces, PPG HTE powders can achieve first-pass efficiency rates of up to 85% or higher. Compared to standard powder coatings, these systems slash powder consumption by 20-25%.
Naturally, contemporary powder coating formulations, optimal equipment maintenance, and a refined application technique can help to improve first-pass build rates. But a transition to today’s generation of HTE solutions can help realize optimal performance for all powder users based on chemistry alone.
A stubborn misconception among applicators who have powder reclamation systems is that HTE technologies are less important than they are for spray-to-waste coaters. HTE solutions actually hold advantages for both types of operations.
Reclaiming powder may not always be feasible, depending on the coater’s capabilities, the number of colors used, and economic factors. Time, labor, and powder quality must all be considered. At the same time, increasing first-pass build rates also mean that more virgin powder is used which tend to be of higher quality in terms of film build consistency, electrostatic charge, transfer efficiency, and cured film appearance than virgin-reclaim blends.
Stepping up to High-Transfer Powder
Because HTE powders have better electrostatic properties than standard formulations, they produce less overspray, which equates to less waste to manage or reclaim. This saves both time and labor.
Coaters that transition from standard powders to specialized, high-transfer formulations make significant first-pass application gains. This is thanks to the chemistry of the coatings themselves, which helps to overcome variables like application technique, equipment and operator skill.
This results in reduced product loss, more uniform film builds, improved operational efficiencies, and cost savings, even on parts with sharp edges.
“These high-transfer efficiency solutions take a lot of the guesswork out of the application process and give applicators a greater degree of control over cost and quality of their production processes,” said Shelley Verdun, PPG business manager for Powder Coatings, Americas, Industrial Coatings.
PPG, a global coatings leader with solutions in every major technology platform, touts an impressive portfolio of powder coatings that are specifically engineered to deliver first-pass transfer rates 20-30% higher than standard powders. These advanced formulations are ideal for architectural building products and general industrial applications like shelving and racks, office furniture, and heavy-duty equipment.
PPG’s HTE Lineup
PPG ENVIROCRON® HIGH-TRANSFER EFFICIENCY powder is specifically designed to provide excellent adhesion on tricky parts and complex-shaped equipment like wheels, wire racking, metal shelving, and other products. ENVIROCRON® HTE powder boasts first-pass transfer rates of 85% or greater and cuts per-item consumption by up to 25%, lowering material costs.
Similarly, PPG CORAFLON® PLATINUM fluoroethylene vinyl ether (FEVE) fluoropolymer resin-based powder coatings for architectural applications offer high transfer efficiency rates of more than 20% and improved corrosion resistance compared to standard FEVE powders. They deliver a fast film build and produce very little waste, even in tough-to-reach cavities.
Meeting FGIA/AAMA 2605 specifications, the highest standards for weathering and corrosion resistance in the industry, Coraflon Platinum offers a 20% higher transfer efficiency than standard FEVE powders. Available in a wide range of colors and textures, including anodized finishes, it offers applicators an expanded gloss range of 5-85 to create aesthetics never before possible in a powder and is specially formulated without major substances of concern.
PPG’s HTE product offerings for architectural applications also include PPG ENVIROCRON® HTE (03) and PPG ENVIROCRON® HTE (04) that meet FGIA/AAMA 2603 and 2604 specifications, respectively. Both powder coatings deliver transfer efficiency ratings of up to 85%.
PPG ENVIROGRON® (03) and (04) are available in a range of colors, glosses, mica and metallic effects. Benefits also include waste saving first-pass transfer efficiency of up to 85% and energy-saving 10-minute cure at 350°F (177° C).
Real-World HTE Uses
After the launch of PPG Coraflon Platinum powder, a leading window manufacturer conducted trials to evaluate the formulation on their line and the finish quality. Coraflon Platinum powder was applied to a difficult-to-coat, geometric-shaped part using the same automatic powder coating line, line speed, air pressures, and voltages as their usual standard powder process.
The high transfer powder deeply penetrated into the recessed areas without heavy edge build up. Even after lowering the powder pressure by 20%, a much better first pass transfer efficiency was achieved, all without sacrificing required film thickness. By transitioning to a high transfer formulation, much less powder is going through the reclaim system, and overall powder consumption has dropped by 20%.
While making the switch to an HTE formulation is optimal, there are other steps that can help to reduce application costs, improve application efficiencies, and improve finish durability and quality.
Better Powder Application Practices
Optimizing spray application coating equipment and operator technique are two ways to increase first-pass build rates. Because of the abrasive nature of powder and the possibility of creating impact fusion, spray equipment requires routine maintenance to maintain proper control of the application process. Applicator nozzles, pumps, and guns that are worn or have impact fusion can clog and hamper air flow, leading to higher material usage, inconsistent powder output, and defects in the finish.
Keeping spray guns, booths, and racks clean is important. So is training employees to operate spray equipment properly and improving application techniques.
Ensuring that a part is properly grounded is also vital to maximize transfer efficiency. Poor grounding of the metal substrate is one of the most common causes of insufficient film build. A full inspection of the application setup to ensure that hooks are clean and all grounding wires are properly attached should be performed continuously.
When not in use, proper powder storage is a must. Beyond storing powder in a tightly sealed container to lock out moisture and contaminants, there are steps that help to maximize the shelf life of powder and its performance.
Since high humidity can negatively influence powder’s fluidization and flow, the recommended temperature range for storing powder is 60°F (15°C) - 80°F (27°C) with 40%-60% relative humidity.
These steps, coupled with the addition of a coating specially formulated to increase first-pass powder build rates help to optimize spray application efficiency.
Moving Powder Forward
In the world of industrial coatings, innovation of powder coatings is changing the paradigm for manufacturers of everything from windows and doors to shelving and racking. HTE powder coatings are among the latest advances in material science, and when paired with best practices, they promote increased durability and efficiency, representing a value proposition for everyone engaged in the life cycle of a product.
PPG is a recognized leader in powder innovation. The company is a global total solutions providers with coatings in every major technology platform, including liquid, pretreatment, electrocoat, and UV/EB cure solutions.
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