Innovations Making Their Way into the Market
Posted on Thursday, March 4, 2021
By Kevin Biller
COVID-19 put the brakes on our industry last March and April when many states opted to enact a shutdown to quell the spread of the novel coronavirus. Production was curtailed, labs were reduced to 50% or fewer employees, and most office workers grabbed their laptops and headed home to set up shop. Fortunately, we have seen a rebound since then. Most powder producers and their allied industry partners have experienced an uptick in business, and with it an opportunity to push some new technology into a commercial realm. This issue’s Technology Interchange will highlight some of the emerging technology and trends.
Shift from TGIC to HAA-based Polyesters
TGIC (Triglycidyl Isocyanurate) has been the predominate curing agent for polyester powder coatings since the 1970s. Primid® XL-552, originally from Rohm & Haas, debuted in the 1980s as an alternative to TGIC. Chemically this material is a beta hydroxyl alkyl amide and is often referred to as HAA. Polyester powders using this crosslinker are also known as TGIC-free.
HAA took a while to gain acceptance in the powder industry; however, a watershed development occurred in the early 1990s when the European Union identified TGIC as a potential mutagen and required new labeling of products containing it. This stern labeling requirement motivated European powder manufacturers to make a major shift from TGIC to HAA-based polyesters. It was a different story in North America, as neither the EPA nor OSHA required such draconian labeling. Consequently, TGIC continued to hold the lion’s share of the market here.
Recently the pace of transition from TGIC to HAA has picked up in North America due to a shortage of supply. Two TGIC producing plants located in China have suspended operations because of environmental compliance issues. This has tightened supply of TGIC and has encouraged powder producers to make a switch to HAA-based polyester powders. Powder Coating Research Group’s 2019 market analysis pegged the North American share of HAA powders at 3.2% compared to TGIC’s robust 43.5% share of the powder market. The current market share for HAA powders is now estimated to be 5.7% and climbing at the expense of TGIC polyesters. This trend is expected to continue throughout 2021.
Sustainability is a widely used but often misunderstood term. It refers generally to the capacity for the biosphere and human civilization to co-exist. In the powder coating realm sustainability can be represented in a number of ways. Obvious examples are the use of recycled materials and products based on renewable feedstocks such as plants. In addition, sustainability can be enhanced with products requiring less energy and that are more durable. The powder coating industry has technology represented in all of these categories.
Bio-Based and Recycled Resin Technology
Sherwin-Williams recently debuted the Powdura® ECO Hybrid Coatings line. The polyester resin used in these powders contains 25% pre-consumer recycled plastic (rPET). The company touts these coatings as easy to apply, with wide cure capability, and can align with third-party certifications such as LEED, GreenGuard, and BIFMA (the Business and Institutional Furniture Manufacturer’s Association).
Battelle Memorial Institute has recently developed a bio- based powder resin that checks two boxes of sustainability—renewable plant-based feedstocks and low temperature cure. This polyester-amide resin boasts 85% bio-based content and is capable of cure as low as 130 degrees Celsius (266 degrees Fahrenheit). In addition, it exhibits excellent UV resistance as evidenced in laboratory testing (4000 hours QUV-B). Prototypes have been submitted to a few powder manufacturers for their support in eventual commercial scale-up potential.
Rilsan Fine Powders, a division of Arkema, has developed a high-performance polymer designed for thermoplastic powder coatings. Rilsan® 11 is a member of the nylon family of polymers and is based on a monomer derived from castor beans. It can be used for a variety of products requiring durability including dishwasher racks, auto parts, potable water pipelines, outdoor furniture, medical instruments, and commercial grade outdoor lighting.
Low temperature cure is another sub-genre of sustainable products. Reducing the energy requirements to cure coatings reduces carbon footprint and saves operating costs. AkzoNobel recently introduced the Interpon Low-E collection of polyester powder coatings, which they say are designed to reduce the curing temperature or curing time, without sacrificing the quality and properties of the coating. They have a curing schedule of between 150 and 170 degrees Celsius (302 and 338 degrees Fahrenheit), from eight to 40 minutes. By using this range, coaters can reduce energy consumption and/or increase the productivity of their application process. This contributes to lower costs and also improves their ecological footprint. Axalta debuted a similar polyester product line called Alesta BE+ in Mexico in 2020.
Longevity of the coating, and hence the durability of a coated item, is another aspect of sustainability. The need to refresh or repaint products is costly, labor intensive, and can involve field-applied coatings with high VOC content. In addition, coating failure that instigates the replacement of a coated item incurs the cost of disposal and ultimate replacement. The powder coating industry recognizes this and has technology that significantly enhances the longevity of a coated asset.
The most common approach to coating longevity is a combination of UV durability and corrosion resistance. Outdoor durable powder coating technology is well- positioned to take on the high-performance architectural market. The North American architectural market abides by the AAMA specifications: 2603 (one year South Florida), 2604 (five years South Florida) and 2605 (ten plus years South Florida). Powder coatings meeting the AAMA 2604 specification have been around for decades and have a sterling track record of performance in the field. These are typically based on “superdurable” polyester binders combined with high performance pigments, fillers, and additives.
Powder coatings that meet the more stringent AAMA 2605 requirements have recently been commercialized and are gaining momentum in the architectural market. These powders are based on FEVE (fluoro ethylene vinyl ether) polymers and can last up to twenty years in UV intense environments such as South Florida. Leaders in this arena are IFS Coatings, PPG, Axalta, ProTech, and AkzoNobel. Prominent building projects have touted the use of AAMA 2605 powder coatings, including the PNC Plaza in Pittsburgh (PPG Coraflon), 55 Hudson Yards (PPG Coraflon), and 10 & 30 Hudson Yards (AkzoNobel Fluromax) in Manhattan.
The current “Holy Grail” of coatings seems to be dictated by the COVID-19 pandemic. Multiple organizations have been feverishly pursuing a solution to stem the spread of the novel coronavirus. Chemical Engineering Journal reports that scientists in China and from the University of Western Ontario have developed an improved technique to utilize silver ions to kill infectious microbes, including the novel coronavirus. Their technique involves chemically bonding silver nanoparticles to silver, copper, and zinc ternary zeolites using alpha lipoic acid then encapsulated by hydrophilic polymers. They claim that this witch’s brew controls the release of silver ions and thereby significantly increases the longevity of efficacy provided by the silver ions. They offer test data that shows a 99.99% of kill rate of various bacteria after 1,200 cleaning solution wipings.
Keyland Polymer has raised the bar even higher with a special antimicrobial technology that can be cured within minutes at 100 to 125 degrees Celsius (212 to 257 degrees Fahrenheit). This technology, called UVMax® Defender, is an option for Keyland’s entire line of UV-cured powder coatings and utilizes silver ion technology to thwart the reproduction of bacterial microbes. UV curable powder coatings are particularly suitable for heat sensitive substrates such as plastic, composite, medium density fiberboard (MDF), and wood. Keyland is targeting applications including healthcare, public transportation, hospitality, education, food service, and consumer goods for this novel product line.
Bonded Metallic Powders
Progress in Organic Coatings published a paper last December that details a new technique to bond metallic particles such as aluminum flake to powder coatings (Figure 1). The concept of bonded metallics is nothing new; however, these researchers hailing from China and Western Ontario have offered a new twist. They have developed a technique using microwave energy, instead of the heat generated from high intensity mechanical mixing, to fuse the metallic particles to the organic powder coating. They claim that the microwave process gets the job done at a significantly lower temperature than the conventional method. In addition, they purport that a higher degree of bonding occurs with their method. It will be interesting to see how these pioneers approach commercializing this kind of process on a production scale.
Instrumentation and Testing
AkzoNobel and BYK-Gardner have teamed up to address an issue that has perplexed the powder coating industry since its inception in the 1960s—how to quantify surface texture. This partnership has developed the spectro2profiler and is said to concisely and consistently digitally measure the textured surface of a powder coating. Up until now, this could only be described qualitatively through visual inspection. This new tool can measure color and gloss, as well as 3D topography of surface texture. BYK-Gardner explains that the spectro2profiler uses a circumferential illumination at 45 degrees with 0 degree viewing. The circumferential illumination is essential to achieve repeatable measurement results on textured surfaces. The extra-large measurement spot with homogeneous illumination guarantees highly reliable and representative readings. This really sounds like a game changer for the appearance characterization of powder coatings.
Also, Defelsko has come up with a new generation PosiTector gage body. This major innovation has a plethora of new features like a larger 2.8-inch impact resistant color touchscreen with redesigned keypad for quick menu navigation which can include touchscreen keyboard for quickly renaming batches, adding notes, and more. This new gen product is more user-friendly with on-gage help that explains menu items at the touch of a button and an updated, stylized user interface retains the same familiar menu structure for easy one-handed menu navigation with or without gloves. Furthermore, durability has been upgraded with a weatherproof, dustproof, and water-resistant IP65-rated enclosure and shock-absorbing rubber holster, which are ideal for the toughest environmental conditions including an unexpected rainstorm. This innovative product is compatible with all the DeFelsko accessories like their coating thickness, surface profile, environmental conditions, hardness, salt contamination, ultrasonic wall thickness probes, and many more.
Application Equipment Software
Powder coating equipment makers have introduced more sophisticated coating application control software in the form of user-friendly apps. Gema’s OptiStar® 4.0 controls crucial coating parameters such as pneumatic and electrostatic parameters. These relevant coating data can be then accessed on your mobile device with their Electrostatic app. Moreover, their DVC technology ensures precise and reproducible powder output and ensures consistent film thickness. Finally, Gema’s PCC and SuperCorona software improves penetration and reduces back ionization, orange peel, and picture framing.
Nordson’s latest and greatest gun control software is Encore® Engage. It features an easy-to-understand, 15-inch touchscreen with modern graphics and intuitive symbol- driven navigation. In addition, a guided recipe feature provides step-by-step navigation with preset options to help operators confidently create new recipes. Video tutorials and guided instructions provide greater visibility to key information and give additional support for critical tasks. For operators around the world, Encore Engage® includes several screen language options and its controller interface delivers easy navigation and enables Industrial Internet of Things (IIoT)/Industry 4.0 functionality for powder coating application.
Parker Ionics has focused on their exclusive Pulse Power gun control technology. Their new GX8500A powder application system features a 3G patented Super Pulse Power corona charging technology that provides superior first pass transfer efficiencies (FPTE) on all shapes and substrates. In addition, it is fully digital with simple controls featuring a 250-recipe capacity. Parker explains that the GX8500A is excellent for coating boxes, wheels, piping, MDF, and extrusions and that it possesses one of the highest transfer efficiencies in the industry, resulting in lower operating costs.
As always, the dynamic powder coating industry is ablaze with introducing innovation and game-changing technology to advance the performance, consistency, and reliability of the finish it gives to a universe of durable products. Hats off to all the erudite technicians, scientists, engineers, and design professionals for all of their inspiring contributions.
Kevin Biller is technical editor of Powder Coated Tough and president of The Powder Coating Research Group.