In the simplest terms, sustainability could be defined as less waste and more efficiency. This could mean fewer processing steps, the use of fewer chemicals or other building blocks, or the ability to develop products that last hundreds of years without the need for constant maintenance.

In the coatings (paint) world, sustainability is usually looked at through the lens of fewer chemicals, biomaterial substitutions, shortened or fewer manufacturing steps, or outright chemical bans. Significant efforts are currently underway to reduce petroleum-based materials in the first place along with trying to make the new products last at least as long as their predecessors.

There is another way to look at materials sustainability. What if the pretreatment chemicals and coatings could be eliminated altogether? What if the oxide was also the color coat? What if the longevity of stainless steel could be exploited together with its oxidation potential? What if color could be imparted onto stainless steel strip using only one production operation for both steelmaking and coloring? What if these innovative ideas were actually more cost effective?

First Steps

In 1971, Allegheny Ludlum Steel Corporation took a step in that direction. While certainly not under the guise of sustainability, the company developed a process that produced black stainless steel for use in formed architectural products.¹ In this case, a stainless steel strip was produced by oxidizing the stainless surface to form a porous oxide coating and impregnating it with an alkali metal silicate, and then drying and fusing the silicate by heating between 1400 and 1600 °F. Temper rolling the finished product—a typical steel finishing process—allowed for flattening the strip to facilitate fabrication.

This process was an efficiency improvement over the original pre-1968 process where many more production steps were used. First, the strip was treated to obtain a black oxide and then coated with a water-soluble alkali metal silicate or a water-based thickened or gelled solution of sodium or potassium dichromate. The next step involved removing the water and subsequently heating the coated surfaces to a temperature high enough to form a uniform, black, porous oxide 1,000–500,000 Å thick. Excess coating and loose oxide were then scrubbed off with water.

In addition to reducing the number of processing steps, the 1971 process eliminated many quality problems. There was better thickness uniformity, less visibility of any spray or rolling pattern, good aesthetics, and better condensing humidity resistance, as depicted by the absence of white residue all over the strip. Steam testing, abrasion resistance, chemical resistance, mandrel bend, and impact testing were also improved to the point that this black stainless could be formed into tubes or building panels with decent aesthetics. With better oxide thickness control, color was also more uniform.

Fast Forward to 2013

Over the 40 years since the first steps in manufacturing blackened stainless, many material inventions and improvements have occurred. Stainless steel itself has become a more uniform product, with improved surface finishes that can now be used in a variety of aesthetic-critical applications. Base metal chemistry modifications and more controlled annealing atmospheres and temperatures have led to increased formability as well.

Alongside steel production maturation, the advent of affordable, usable nanotechnology opened a huge window for surface modification. Nanoparticle surface treatments were developed to reduce damaging oxidation and corrosion of stainless steel and other alloy components in oxidating and corrosive conditions.²

Improving the longevity of stainless steel at elevated temperatures was the genesis of this development. Power generation plants often have problems with damaging oxidation from accelerated high-temperature fire-side corrosion due to molten alkali salts. Other problems include accelerated medium-temperature fire-side corrosion due to low oxygen activity environments and the presence of sulfur and steam side oxidation of tubing, piping, and valves in fossil fuel-fired boilers.

Pressure has been placed on power plants to increase efficiency, meet stringent environmental regulations, and ensure plant reliability, availability, and maintainability—ideally while minimizing costs.³

Some of the nanoparticles used as surface treatments for corrosion and oxidation resistance include aluminum, silicon, scandium, titanium, yttrium, zirconium, niobium, lanthanum, hafnium, tantalum cerium oxide (nanoceria), and thorium. These nanoparticles do not really form coatings but rather are doping agents that become embedded within the oxide structure.

Over time, yttrium has become a preferred nanoparticle for these types of applications. Yttrium, particularly in the form of yttrium oxide nanoparticles (Y2O3 NPs), is considered superior because of its exceptional properties around high thermal stability, strong chemical stability, mechanical strength, and strong corrosion resistance. Perhaps the greatest attribute under the veil of sustainability is that yttrium has low toxicity. Because of its low toxicity, this nanoparticle is often used in biomedical applications.

Minimox® is one of the yttrium-based, self-protective alloy treatments that minimizes oxidation of alloys at elevated temperature. It changes the structure and/or chemistry of the thermal oxide, which becomes denser and more adherent than thermal oxide without Minimox® doping. Flaking, protrusions, and microvoids are eliminated, resulting in a smooth, dense, adherent surface.⁴

Depending upon the time and temperature of the annealing process, thin film oxides can be grown to thicknesses between 500 and 9,000 Å (1 Å = 0.1 nanometer). Oxidized surfaces doped with yttrium are characterized by excellent cyclic and isothermal oxidation, corrosion resistance in severe environments, and high resistance to severe heat and chemical environments. As a bonus, the thickness of the oxide can be controlled within a high-temperature annealing atmosphere to purposefully impart color onto a metal surface.

Modern Colored Steel

The black stainless steel for architectural applications referenced earlier in this article did not result in large volumes of product released into the field. Despite the excellent properties derived from the surface modification, stainless steel was too expensive for run-of-the-mill building applications. However, the idea of a black surface that did not require painting simmered in the background for many years. The thought of being able to colorize a surface using existing in-line annealing practices was a tantalizing thought. Black stainless manufactured using the existing in-line annealing process, without the addition of either paint or doping agents, was successfully accomplished in 2018.⁵ However, stainless remained an extremely expensive substrate for many applications.

It was determined that other substrates that were more in line with cost constraints of industries, such as appliance and automotive, would also benefit from this oxide modification methodology. Electrogalvanized steel (EG) was textured to the required product finish and the zinc coating was subsequently annealed. The resulting black substrate met all the requirements of appliance finish specifications for refrigerator door applications (the most stringent requirements in the appliance world). This “faux stainless” EG product was compared to black polished stainless and the GE Black PVD standard, and it was found to meet all requirements, including color (Figure 1), gloss, stain/aging, anti-fingerprinting, corrosion resistance, and mechanical properties—all at a much lower cost.

FIGURE 1 Black color comparison between standard product, black stainless steel and “faux stainless steel” textured electrogalvanized.

Finally, in 2023, a method of colorizing stainless steel using yttrium doping and annealing was developed. To prove the concept, stainless steel coils were coated with an aqueous yttrium pretreatment solution and batch annealed for several hours to oxidize the surface. Batch annealing is not particularly uniform, and is not the streamlined process of choice, but enough of the coil exhibited the required properties to move forward and optimize the process.

The basic idea was to dope the surface with an aqueous yttrium nano-solution using an in-line roll coater, followed by continuously annealing the strip while varying time and/or temperature in the annealing furnace to grow the oxide and obtain the desired color.⁶ Even keeping the annealing furnace atmosphere constant, varying line speeds (time in anneal) can allow for the efficient production of different colors. (See Table 1.) These colored stainless coils were fabricated and placed on structures in the Nashville, TN, area (Figure 2) and are still in place today.

FIGURE 2 Colored stainless panels on structures in the Nashville, TN, area.

All the aforementioned work has culminated in less waste and more efficiency. Technological improvements in substrate quality, steel processing, and nanotechnology have bolstered the development of a variety of products previously deemed impossible, too expensive, or of insufficient quality for commercial production. By looking at outside-the-box alternatives, it is possible to obtain color by manipulating the oxide and removing the organic coating completely.

References

1. Helgert, Harold. L; et.al. Method of Making Black Stainless Steel Sheet. U.S. Patent 3,556,871, January 19, 1971.
2. Kerber, Susan J. Nanoparticle Surface Treatment. U.S. Patent 8,568,538 B2.
3. Stott, F. H. Influence of Alloy Additions on Oxidation. Materials Science Tech. 1989, 5 (8), 734.
4. Material Interface Inc. Protecting Furnace Components with Minimox® Alloy Treatment. Minimox® Product Data Bulletin. 2016.
5. Myers, F.A. Black Steel. AK Steel Presentation, 2018.
6. Myers, F. A.; Price, L. R. Method of Colorizing Stainless Steel Using Strip Anneal Processing. U.S. Patent 11,584,997 B2, February 21, 2023.

Cynthia A. Gosselin, Ph.D.,��is director at The ChemQuest Group,��www.chemquest.com. Email:��cgosselin@chemquest.com.

Electrification has been a hot topic for the last few years. The aging power grid where 30% of electric lines are approaching their typical 50- to 80-year lifecycle, leading to brownouts in the western United States. Artificial intelligence (AI) advancements that require exponentially more power than traditional data centers, crypto mining, and a growing population that is using more and more electronics are causing hook-up bottlenecks, particularly for clean energy, large users, new technologies, and an increasing number of consumers.

Adding to these needs, the North American Electric Reliability Corporation predicts that rising peak demands, projected capacity deficits, fuel vulnerabilities, and insufficient dispatchable resources are risks to the availability of power if growth of transmissible power stalls. The ever-increasing energy needs and the vulnerability of our current resources have Microsoft partnering with Constellation Energy to reopen Unit 1 at the Three Mile Island nuclear plant as the Crane Clean Energy Center to provide enough power to operate their projected AI data warehouses.¹

On October 18, 2023, the U.S. Department of Energy (DOE) announced up to $3.5 billion for 58 projects across 44 states to strengthen grid reliability nationwide.² In order to achieve these goals, it will be necessary to manufacture a significantly larger number of transformers and generators. Each of those pieces of equipment will require electrical steel laminations with highly specialized coatings to meet power requirements, insulation levels, durability, corrosion resistance, and temperature resistance to improve energy efficiency.

This projected growth is so important to the national economy that Cleveland Cliffs, a large producer of electrical steel in the United States, announced plans in 2022 to repurpose a shuttered tin-plate facility to produce state of the art electrical transformers in Weirton, WV.³ Lourenco Goncalves, chairman, president, and CEO of Cleveland Cliffs, has emphasized the critical shortage of electrical transformers and its impact on economic growth throughout the country. He has famously stated there will be no AI without electricity and there will be no electricity without transformers.

The global electrical steel coatings market was valued at $304 million in 2023 and projected to grow at a 5.3% CAGR to $490.3 million from 2024 to 2032. Growth will be driven by an increasing need for energy-efficient transformers and electric motors as industries strive to reduce energy losses and meet various environmental regulations. The chromium-containing segment is currently 42%, with the C-5 coating segment valued at $198.1 million.⁴ North America is a prime market due to industrial automation, growth in the EV market, high consumer spending, industrial technology advancements, and the competitive growth of energy-devouring AI initiatives.

Grain Oriented Electrical Steel (GOES) has the largest market share because it can generate magnetic flux while at rest and not rotating. This is the best electrical steel for large, high-performance generators and energy-efficient and traditional transformers because of superior magnetic properties. GOES exhibits lower core losses, strong magnetic directionality, and superior magnetic permeability (amount of magnetization produced in response to a magnetic field). Grains are parallel to the rolling direction. Absolute magnetic properties are dependent upon the heat treatment imparted during production.

Non-Oriented Electrical Steel (NOES) is used primarily for rotating equipment such as electric motors, generators, and over-frequency and high-frequency converters. Both types of steel chemistries contain varying levels of iron (93–98% by weight), silicon (1.2–3.5% by weight), and chromium (0–1.5% by weight). Trace elements of raw materials and/or alloying elements are also present, including aluminum, boron, calcium, carbon, columbium, copper, manganese, molybdenum, nickel, phosphorus, sulfur, titanium, and vanadium.⁵ Electrical steels are coated according to ASTM A976-18 Standard Classification of Insulating Coatings for Electrical Steels by Composition, Relative Insulating Ability, and Application.

Electrical steels are sold as either semi-processed or fully processed. The main difference is that semi-processed steels receive the final heat treatment subsequent to punching into the required shape while fully processed steels are sold with an insulating coating, full heat treatment, and specific magnetic properties.

Rembrantin, Axalta, and Chemetall are well-known global electrical steel coatings suppliers, and Henkel provides a product within the United States. All have recently increased their offerings to include chromium-free and/or formaldehyde-free alternatives to meet current or potential environmental regulations.^6,7,8

There are nine categories of electrical steel coatings currently documented in ASTM A976. Table 1 lists the chemistries of the various coatings. Table 2 provides a description of the coating characteristics for each classification.

The electrical steel coatings market has been growing over the past few years and is slated to play an ever-increasing leading role in the facilitation of all aspects of electrification equipment for upgrading the power grid, enhancements for AI power generation, and clean energy initiatives in the industrial sector.

Cynthia A. Gosselin, Ph.D.,��is director at The ChemQuest Group,��. Email:��cgosselin@chemquest.com.

References

In George Pilcher’s 2024 state of the paint industry article, he explains that supply chain issues still have not fully recovered from the challenges wrought by COVID-19.¹ Initially, it appeared that 2023 was going to be a year when the pandemic-related supply chain problems stabilized. Unfortunately, in the second half of 2023, new challenges evolved and spread, upending much of the progress brought about by adding manufacturing capacity closer to home, adjusting inventory levels to accommodate availability, and decreasing lead times.

This time, shutdowns related to COVID-19 were not the culprit. Rather, a more insidious set of circumstances were and are at work to stymie the almost-reestablished post-COVID supply chain: Houthi forces and La Niña.

COVID-related issues caught everyone off-guard without measures in place to shore up long-held just-in-time delivery practices. During COVID, just-in-time began to be replaced with just-in-case deliveries. Reshoring became very popular. Many companies’ manufacturing processes returned from Asia to be closer to customers in the United States, Mexico, Central, and South America. Unfortunately, as the supply chain stabilized in 2023, some importers went back to just-in-time deliveries, completely negating one important lesson learned during COVID.

In 2023, many ships that had been built during the pandemic were placed into service. Freight rates dropped due to vessel overcapacity, causing shipping prices to tumble. Shippers and customers started to relax, transportation costs came down, and prices fell to more reasonable levels—albeit not necessarily to pre-COVID rates.

Then in late 2023, tensions exploded in the Middle East. The instability in the region is the most obvious problem affecting supply chains in all markets. Any shipper that depended upon the Suez Canal or the Red Sea had massive logistical headaches. During normal operations, 15% of world trade passes through the Red Sea². However, starting in the first 11 days of January 2024, Egypt reported a 40% drop in revenue from transit fees as reported by the Suez Canal Authority’s Admiral Osama Mournier Mohamed Rabie.²

As the Israeli-Palestinian conflict escalated, Houthi forces began to attack cargo ships in the Suez Canal and the Red Sea. Commercial ships are huge, but they are poorly equipped to absorb missile and drone attacks. Any ships navigating the Red Sea had to depend on the U.S.-led Maritime Coalition for protection. The Bab-el-Mandel Strait into the Red Sea from the Asia side was essentially shut down: ships that were lined up for miles were often hijacked while waiting to get through.²

The inability to navigate the Suez Canal was a major catastrophe. Recall that in 2021, the Ever Given, a container vessel operated by Evergreen Marine, got stuck in the canal and that halted traffic for a week. The blockage stopped 369 ships from passing through the canal and delayed an estimated $9.6 billion worth of trade each day.⁴ The effects of that comparatively small delay impacted supply chains for up to nine months.

In the 2000s and 2010s, Somali pirates were a threat. Today, drones, drone strikes, and waterborne IEDs are a bigger problem. Clearly, the ongoing Middle East issues are going to have a much larger impact on supply chains than a one-week stoppage because of a stuck ship.

Now, through lessons learned from the complications related to COVID-19, initial response times were shortened. Major shippers such as Maersk and Hapag-Lloyd immediately rerouted ships around South Africa to protect the containers—lengthening transportation time by at least 25% and increasing costs exponentially.³ But at least shipments were not brought to a halt or otherwise destroyed.

On top of that, all the new ships languishing in ports after the pandemic were suddenly needed to shore up the longer routes and shipping times. Freight rates rose dramatically, but the consolation was that COVID rates were still five times higher than the new rate increases.

As if the Middle East didn’t pose enough significant challenges for container-vessel transit and supply chain disruption, there was another major issue brought about by La Niña in North America. The lack of rainfall during the wet season in 2023 caused severe drought conditions, dropping the depth of Gatun Lake to dangerous levels. The Panama Canal reduced traffic due to this historic drought, which saw water levels fall to the lowest since 1965. In addition to impacting the drinking water available for that region, the lake did not have enough water to spill over into the Panama Canal. It became “too dry”—rather, too shallow—to permit the usual number of shipping vessels to traverse the canal without an advanced reservation.

For ships that needed to move from the Atlantic to the Pacific side, reservations were (and still are) as difficult to obtain as an uber-exclusive 5-star restaurant in New York City. Ships without reservations must resort to an auction for a passage slot. The opening bid was $55,000 over the regular tariff—one confirmed bid was $4 million! Bloomberg reported that in November 2023 alone, shipping companies have paid $223 million above transit costs just to get a slot.⁵ And they still must wait for days before passage is finally allowed. However, the wake of these large ships causes water to spill out of the canal if they are too close together, which further lowers the water level. In November 2023, as conditions worsened, the Panama Canal Authority reduced daily transits to 24 from the normal of 34–36, and further reduced them in 18 in January. This continued into the third quarter of 2024.⁵

Fortunately, the Panama Canal Authority anticipates much higher rainfall during the 2024 May to December rainy season because of the weather shift to El Niño. The refilling of Gatun Lake has allowed for an additional booking slot beginning August 5, 2024. Drafting regulations have been eased, allowing for additional ships to pass at the same time. A proper rainy season could lead to normal operations by fall 2024.⁶

What does this all mean for the coatings industry?

On the plus side, because of the lessons learned during COVID, there is now some level of stabilization and predictability. PVC resin prices held steady in June remaining below 2023 levels.⁷ On the other hand, the hurricane season is expected to be especially active in the Gulf region where many PVC manufacturers are located. Hurricane Beryl already made an early appearance in Texas.

Another plus is that industries tangential to the coatings industry have also made significant supply chain modifications that will benefit our products. For example, GE Appliances (a subsidiary of China-based Haier Smart Home) in Louisville, KY, remade their supply chain more flexible after coping with product shortages during the pandemic.⁸ Admittedly, they began the process in 2017. The pandemic forced the acceleration of those plans as they struggled with over and under stocking of major appliances.

The largest change GE Appliances made was to bring manufacturing from Asia to the United States, which added 4,000 manufacturing jobs. For the company, this change cut shipping costs, reduced transit delays, allowed better control of production, strategically located inventory levels, and generated consumer goodwill with the new jobs. For the tangential industries such as coatings and metals, these manufacturing sites turned into new, large domestic customers.

In addition, GE Appliances balanced inventory by tracking customer orders delivered on time and in full–thereby prioritizing existing orders. The cascading effect was that because many appliances are painted scheduling those needs were also better managed. Pretreatment and paint suppliers were better prepared to provide products as needed, instead of way ahead, too far behind, or as an emergency.

Although the situation in the Panama Canal will most likely resolve itself later this year, there are still going to be significant challenges within the supply chain. Ocean shipping costs will remain very high as long as the Middle East remains unstable and hostilities keep the Suez Canal a shipping nightmare. Increased lead time will continue for core commodities well past any cessation of hostilities.

Pressures due to ongoing freight and raw material pricing will continue to drive cost pressures this year.⁹ Section 301 tariffs that went into effect on August 1 will impact just about all commodities — although this can be mitigated by bringing manufacturing back onshore.

Another pressure on the coatings industry is the price of crude oil. Many raw materials used in oil and acrylic paints are derived from petroleum. A $10 rise in crude oil equals a 3% rise in paint manufacturing cost.⁹ A gallon of top shelf house paint sold for approximately $30 in 2017. That same gallon of paint at the same store is now at least $60. (I can vouch for this as I keep receipts!)

Resiliency, flexibility, and excellent planning will be the attributes that help meet the challenges of ultimately stabilizing the supply chain for coatings and tangential industries this year and into 2025.

Cynthia A. Gosselin, Ph.D., is director at The ChemQuest Group, ChemQuest Technology Institute, and ChemQuest Powder Coating Research. Email: cgosselin@chemquest.com.

References

1. Pilcher, G. The State of the U.S. Paint and Coatings Market 2023-2025: Slow and “Steady as She Goes.” CoatingsTech. 2024, September/October.
2. Hunnicutt, T. etal. US Strikes Houthi Anti-Ship Missiles, Shipping Disruptions Grow. Reuters Business. January 19, 2024
3. Neuman, S. As Houthi Attacks on Ships Escalate, Experts Look to COVID Supply Chain Lessons. NPR, Jan 20, 2024.
4. 2021 Suez Canal Obstruction. https://en.wikipedia.org/wiki/2021_Suez_Canal_obstruction (accessed July 31, 2024).
5. Panama Canal Warns of “Indefinite Delays” as it Offers Special Auction Slot. The Maritime Executive, Nov 23, 2023.
6. Panama Canal Traffic to Increase as Drought Conditions Ease. Oil & Gas Journal. https://www.ogj.com/, June 28, 2024.
7. Border States website. Border States Supply Chain Update—July 2024. Border States. https://solutions.borderstates.com/news/border-states-supply-chain-update-july-2024/ (accessed July 31, 2024).
8. Young, L. Supply-Chain Overhaul Boosts GE Appliances’ Sales. Wall Street Journal, Heard on the Street, July 8, 2024; p B10.
9. On the Job with Behr (blog). 2024 Paint Industry Outlook: Exploring Headwinds & Tailwinds in a Dynamic Marketplace. Behr Pro website. Published February 2024. https://www.behr.com/pro/onthejob/blog/2024-paint-industry-outlook/ (accessed July 31, 2024).

Background

Is circular thinking new? When and why did linear thinking become more popular? To begin, let’s look at some history in mass production and consumerism to see how the paint and coatings industry has evolved into the supply streams seen today.

In the 1920s, a term began to be discussed within the mass production automotive industry. Alfred Sloan, a GM executive, is credited with the first use of the term “dynamic obsolescence” — a term used to describe the planned obsoletion of cars.¹��The intention was to entice consumers to want to purchase newer models before the older ones were beyond their useful life. New models were designed to make the previous ones less desirable—some were even designed for a limited life. The 1923 Chevrolet is often cited as the first such example.

Later the term evolved into “planned obsolescence” and was accepted as a principle of mass manufacturing. In his 1932 essay, Bernard London proposed the idea of “Ending the Depression Through Planned Obsolescence”—an approach that drew criticism. In the 1960 book��The Waste Makers, Vance Packard scrutinized the concept, calling it “the systematic attempt of business to make us wasteful, debt ridden, and permanently discontented individuals.”²

As mass production, consumerism, and convenience became part of post-World War II life, another term emerged: “Throw Away Living.” First used in an article from the August 1, 1955, issue of��LIFE��magazine, the term was used in the author’s “critical view of over consumerism and excessive production of short-lived or disposable items over durable goods.”³

Even so, consumers had not always been part of a “Throw Away” culture. In fact, pre-World War II thinking was more focused on not being wasteful. There was value in repurposing items for new uses. A good example of this is how flour was marketed to consumers during the post-Civil War period through the 1950s. During this time, textiles were used to replace barrels in the transportation of dry goods. It was common for the consumer, who did not want to waste, to make clothing and other articles from the leftover flour and feed sacks. Manufacturers took note of the trend and began to print attractive patterns on their packaging, an example of��public-desired reuse. They also printed their product branding in washable ink and gave the consumer instructions on how to remove it, illustrating��manufacturer’s design for reuse. Once the clothing was no longer useful, the textile was again repurposed into quilts and rag rugs, showing an��end-of-life repurpose.

Circularity in the Chemical Industry

Maria Morais, in��The Future of Commerce, states that “91% of the global economy is not circular and that this represents a $4.5 trillion profit opportunity for the industry.”⁴��Chemical industry CEOs such as Markus Steilemann of Covestro have recognized that there is value in everything we generate. Steilemann has publicly stated many times that “We will be fully circular.” He says to achieve this goal there are four key pillars to realizing a circular economy:

1. alternative raw materials
2. innovative recycling
3. joint solutions
4. use of energy

As shown in��Figure 1, there are many places where circularity can be brought into the value chain. First, biobased feedstocks and reusable base chemicals from��chemical recyclers��can be used as raw materials which are sold to the��base chemical producer. These feedstocks flow through the value chain ultimately to the��end user. After which at the end of life, physical recycling, chemical recycling, or composting can bring these valuable materials back into the value chain to be used again.

FIGURE 1 Circularity in the coatings industry.

This article focuses on three areas:��alternative raw materials, such as��renewable feedstocks��and��mass balance feedstocks; the��use of energy��in application and curing; and, finally, the use of��joint solutions��in reducing emissions by utilizing high-performance water-based solutions to reduce emissions of carbon-based solvents. These will enable a coatings formulator to develop products with more circularity and sustainability built into them. The largest impact a coatings formulator can make is in the reduction and dependency on fossil-based raw materials. By focusing on these three areas, the formulator will have a direct impact on the circularity potential of their formulation. This transition will have the largest impact in reducing the overall CO₂��footprint caused by coatings and processes.

¹⁴C Verified Renewable Feedstocks

Renewable feedstocks are those that can be��¹⁴C verified for bio-content. This means that their original source of carbon was plant based and not fossil based. In the polyurethane industry, great strides have been made to produce some of the key starter materials from biomass. Nonedible sugars from corn starch, wood, and straw can be converted through a bio-catalysis with micro-organisms to become amine starter materials. Three key amines in the polyurethane coatings industry are aniline, pentamethylene diamine, and hexamethylene diamine.

Bio-aniline is a very versatile building block. Today, its fossil-based alternative is a key raw material in the production of diphenylmethylene diisocyanate (MDI). MDI currently is the world’s largest volume diisocyanate produced. It is used in applications from mattresses, bumper foam, adhesives, and even polyurethane coatings. Bio-aniline will improve the CO₂��footprint of the aniline process and is based on non-edible food feedstocks. Steilemann says, “Being able to derive aniline from biomass is another key step towards making the chemical and plastics industries less dependent on fossil raw materials.”

Pentamethylene diamine (PDA) is another biobased amine that is based on non-edible corn starch. When converted to the pentamethylene diisocyanate (PDI), it will contain 71%��¹⁴C verifiable carbon. As a polyisocyanate trimer, which is a polyisocyanate structure in coatings industry, it is very comparable to its fossil-based alternative, hexamethylene diisocyanate (HDI).��Figure 2��illustrates the performance comparison of a fossil-based HDI trimer compared to the biobased PDI trimer. Here, it is demonstrated that there is no performance loss when switching to a biobased PDI trimer.

FIGURE 2 Performance comparison of PDI- and HDI-based trimers in a solventborne clearcoat.

Developments are also on the way to replace fossil-based hexamethylene diamine (HMDA) with a biobased alternative. This would allow for the production of biobased HDI. The current manufacturing process to make HMDA starts with the hydrogenation of adiponitrile that is produced from fossil-based butadiene. Through partnerships with Genomatica and Covestro, a biobased HMDA has been created. Polymers made from this biobased HDI have the benefit of 14C content along with being able to use current TSCA and DSL registrations because it is indistinguishable from the fossil-based HDI

The other side of any polyurethane formulation is the resin. Typically, the largest contributor to the mass of a polyurethane, adipic acidbased polyesters are a key type of polyesters. Here, the 14C verifiable biobased succinic acid and sebacic acid have shown to be a good replacement for adipic acid in polyester manufacturing. When producing polyurethane dispersions with these biobased polyesters, a product with a renewable content as high as 65% is achievable.��Figure 3��illustrates the reduction in global warming potential when switching to these biobased alternatives.

FIGURE 3 Global warming reductions comparing biobased polyesters to fossil-based polyesters.

When using these biobased building blocks, the formulator will no longer experience a reduction in physical properties previously expected with biobased raw materials. In some cases, such as oxidatively curable biobased building blocks, which are incorporated into a polyurethane dispersion, the resulting coating performs better than many of the competitors and can even compete with 2K options.

Figure 4��is a generic representation of how fatty acid biobased polyols are incorporated into oxidatively curable polyurethane dispersions.

FIGURE 4 Oxidative curable polyurethane dispersions having fatty acid-based polyols.

An example of is this biobased polyurethane dispersion is in a wood floor clear coating. With a 14C verifiable bio content of 49%, it has shown to be comparable to 2-component (2K) coatings on the market today.��Figure 5��illustrates its performance against market standards in 1-component (1K) and 2K water-based wood floor coatings.

FIGURE 5: Comparison of oxidatively curable 1K clearcoat to market standards.

Certified Mass Balance Feedstocks

Mass balance is a��certified manufacturing method��that uses biobased and recycled feedstocks very early at the base chemical producer area of the circular value chain. ISCC+ (International Sustainability and Carbon Certification), an accreditation body, certifies each step along the value chain. Mass balanced materials are not��¹⁴C verifiable but are ISCC+ certified. Illustrated in the green circle in��Figure 6��is where the certification process starts. Along each step of the value chain the ISCC+ certificate is passed along, and the next step is then verified until reaching the end user.

FIGURE 6 How mass balance is incorporated into circularity.

At the��base chemical producer, renewable feedstocks, reusable base chemicals, and those from fossil-based feedstocks are blended in the process to make a base chemical. ISCC+ certifies and attributes a certain part of the production as biobased based upon the amount of biomass and recycled material in the process minus process scrap and expected yield. These certificates follow through each part of the value chain and ISCC+ will certify each step along the way. The role of��mass balance��is to accelerate the use of biomass and recycled materials without the need for new manufacturing facilities, new manufacturing processes, regulatory listings, and even final product validations. This process will reduce fossil resource consumption, waste streams, and environmental footprint. Mass balanced materials can be substituted for purely fossil-based ones without the need for reformulation or performance recertifications.

The list of available mass-balanced raw materials and volumes are growing every day. Many of those common raw materials for polyurethanes are now available. Isocyanate monomers such as MDI and TDI and aliphatic amines such as HMDA and IPDA are available today. Polyester building blocks, such as adipic acid, butanediol, hexanediol, neopentyl glycol, and trimethylolpropane, are available as well as solvents such as ethyl acetate, butyl acetate, and solvent naphtha. Incorporating these building blocks into product development help all of us reach our circularity goals.

Use of Energy

The use of energy is a key part in reducing the use of fossilbased materials. Here, the choice of a coating technology can play a crucial role. This can sometimes be a challenge for the coatings formulator because they are often constrained by a particular production line. A coating must be designed to work within this production line without the need for new construction or redesign. Performance is also key. End users are not willing to sacrifice performance to gain circularity benefits. The formulator must deliver on all three. For production lines that are designed to be baked, end users often wish to reduce their energy cost and increase efficiency. For these applications, thermolatent hardeners and polyaspartic coatings are two technologies that will do just that.

A thermolatent hardener is an HDI-based polyisocyanate trimer that will have a similar pot life to that of an uncatalyzed (no dibutyltin dilaurate) 2K polyurethane formulation.

Figure 7��illustrates three 2K solvent-based polyurethane coating formulations. Standard is uncatalyzed, catalyzed is a high-catalyst amount designed for fast oven cure, and the thermolatent is in blue. As shown, after mixing at room temperature, the thermolatent hardener behaves much like the uncatalyzed formulation. Once in the oven, the thermolatent formulation behaves much like the highly catalyzed one offering a triggered cure.��Figure 8��shows an actual coating line for a plastic bumper.

FIGURE 7 The “Snap Cure” characteristics of a thermolatent hardener.

FIGURE 8 Typical real-life bumper coating line.��

For the bumper coating example, an uncatalyzed coating is used. This is because it will give the best surface finish. It requires three baking zones and a significant post cure. This is because properties are not yet fully developed immediately out of the oven. Stacking and packing will usually occur sometime later. The highly catalyzed formulation is not shown as it did not have the appearance qualities required for the bumper. As illustrated in��Figure 9, using the thermolatent hardener reduced the curing zones by two. This allows for faster stacking and packing of bumpers without damage. Energy reductions due to ovens were more than 65%. In this example, the thermolatent hardener reduced the cycle as well. Cycle time per bumper was reduced and throughput was increased by 30%.

FIGURE 9 Less energy and greater throughput possible with thermolatent hardener.

Polyaspartic coatings are another type of fast cure coating that does not require any heating for curing and can be applied using conventional 2K polyurethane spray equipment. Polyaspartic coatings are also known for being lower in VOC than other solvent-based polyurethanes. A polyaspartic is the reaction of an aspartic acid ester, a type of hindered secondary amine, with an aliphatic polyisocyanate. (See��Figure 10.) The most common crosslinker used is a low-viscosity, HDIbased polyisocyanate trimer.

FIGURE 10 The polyaspartic reaction scheme.

Polyaspartic coatings are known for improving coating efficiency. In many applications, polyaspartics can be applied directly to sand blasted steel in one coat with enough thickness to pass C3 corrosion protection. The elimination of a layer not only improves efficiency but also associated VOCs from the primer layer (Figure 11).

FIGURE 11 reduced numbers of layers and elimination of baking contribute to efficiency improvements.��

This reaction is not accelerated by baking. Ambient atmospheric moisture is the catalyst for this reaction. The combination of physical attributes and curing needs were crucial in a light pole manufacturer being able to move from a baked 2-layer system to the single coat, ambient-cure polyaspartic. Because the process allowed for the curing ovens to be turned off, this manufacturer was able to save 75% of its energy cost.

The 40-minute ambient cure represented a 70% reduction in the coating process time per pole. Also, because polyaspartic can be electrostatically applied, the manufacturer also saw a 75% reduction in overspray.

Reducing Carbon through Reducing Emissions

Moving from solvent-based coatings to water-based coatings is a really good way to reduce the overall amount of carbon used in the coating process. In 2000, Bayer Corp. (now Covestro) won the Presidential Green Chemistry Challenge for the invention of 2K waterbased polyurethane coatings.⁵��The crucial innovation in this invention was the development of polyisocyanates that could disperse in water without the use of external surfactants.^6,7

Figure 12��illustrates the three types of modified polyisocyanates most common today in 2K water-based polyurethanes. Nonionic types can be a prepolymer or a higher functional prepolymer, such as an allophanate-modified prepolymer. Ionically modified polyisocyanate are powerful in making emulsions and offer the highest level of hardness and chemical resistances. Typical co-reactants are hydroxy functional urethane dispersions or acrylic emulsions.

FIGURE 12 The three types of modified polyisocyanates used in 2K water-based polyurethanes. 40 PAINT.

Since 2000, these materials have been very successful in producing water-based polyurethane coatings with physical properties that rival traditional solvent-based ones. Successful market applications include concrete coatings, wood floor coatings, automotive plastic, primer coatings, and weatherable external metal coatings. Key features for these markets are 2K performance with organic solvent reductions of up to 99%.

With the potential loss of Oxol 100 as an exempt solvent, there will be an increased need for 2K water-based coating formulations. Primer surfacers are one of those key application areas that rely heavily on exempt solvents. When Oxol 100 is delisted as an exempt solvent, formulations that now report a VOC of 2.1 lb./gal will increase to 3.5 lb./gal because Oxol 100 will again be included as part of the VOC calculation— and 2K water-based polyurethane will looked to as a solution. Today, formulations have been developed that hit the key performance parameters of a primer surfacer (Figure 13) and are able to do this at 1.75 lb./gal VOC without any exempt solvents being used.

FIGURE 13 The physical properties of a 2K water-based primer surfacer.��

Another successful application for water-based polyurethane has been in the replacement of solvent-based rubber for temporary peelable coatings applications (Figure 14). In the automotive industry, the use of temporary coatings has been growing in aftermarket customization and protection. In this application the current solvent-based market standard has a VOC in the order of 5 lb./gal with 8 to 12 application coats needed to achieve a peelable coating. By switching to this 1K polyurethane dispersion, the use of organic solvent was reduced by 96% to a 0.2 lb./gal level. Performance benefits were also seen.

FIGURE 14 Comparison of oxidatively curing polyurethane dispersion to SBR peelable coatings.��

The market is also calling for another key attribute: to reduce coating layers. By using the 1K water-based polyurethane, the number of coating layers is now 3 to 5 layers. This is a reduction of about 60% and an improvement in efficiency. Gasoline resistance was another key attribute that the 1K waterbased polyurethane has that the market-leading solvated rubber product does not have.

Conclusion

It can be challenging for coatings formulators to incorporate sustainability and circularity into their product development. However, through using alternative materials, designing for less energy use, and working together, we can achieve the goal of moving from linear to circular value chains. We can reduce carbon usage, use waste as a valuable feedstock, and reduce our CO₂��generation associated with making and applying high-performance coatings. As more and more sustainable and circular chemical streams come online, the future of sustainable and circular product development will become commonplace.

Mike Jefferies��is the business��development manager at Covestro. Email:��mike.jefferies@covestro.com.

References

By Cynthia A. Gosselin, Ph.D., The ChemQuest Group

As discussed in Part One of this two-part series, it is quite the technical feat to develop marine coatings and methods that keep the submerged portion of the hull free from sea creatures and corrosion without also destroying everything in the vicinity. The many efforts underway to accomplish this are represented in the fact that 64% of the $8.7 billion marine paint market is dedicated to this endeavor. The complex underwater scenario is rarely seen by spectators watching yachts, fishing boats, sailboats, and commercial shipping vessels sail majestically away to their maritime adventures.

What is seen is the part of the boat that is above the waterline. The beauty and majesty associated with boats is represented by topside coatings that impart gleaming paint jobs that are the icon of yacht-quality maintenance—and the goal of all boat owners. Aesthetics are very important and affect the ranking and resale value of a vessel.

Topside paint is, technically speaking, not considered “as important or complex” as bottom boat paint, but it does provide corrosion resistance and significant protection against UV rays. Weeks of sun exposure without “sunscreen” can damage the surface of boat hulls and gunwales just as dramatically as skin can sunburn and blister.

Topside coatings are formulated specifically for the substrate to be painted. Many modern boats have fiberglass hulls, but there remains a significant market for wooden boats among enthusiasts, classic boat owners, and traditionalists.

From Air to the Sea

The genesis of modern topside boat paint occurred in 1973 when two Eastern Airline pilots persuaded Merritt Boat & Engine Works to paint their boats with a coating called Alumigrip that, until now, had only been used on planes flying at 450 knots (517 mph). The coating seemed immune to UV degradation and was extremely hydrophobic. The results were so stunning that US Paints decided to market the product for the marine industry.

Through a series of bar discussions and poor handwriting, Alumigrip became Awlgrip —perfectly (albeit accidentally) named for the marine industry. The new coating process consisted of an epoxy primer and a sprayed linear-polyurethane coating. Ted Turner, winning the 1977 America’s Cup in a record four-race sweep sporting a beautiful Awlgrip topcoat, propelled this coating technology to the top of the marine world. Since then, polyester and acrylic-modified polyurethane topcoats have been added to the product line, providing the same UV and corrosion resistance and hydrophobicity of the original experiment. In the 50 years since the inception of this product, it has become the go-to paint system for the marine and yacht market.¹

Liquid Coatings

Today’s maritime world still has expensive yachts, wealthy boat owners, and less-than-handy boat enthusiasts that commission commercial painting and maintenance for their vessels using only the top-of-the-line coatings. But similar to other industries, the Do-It-Yourself (DIY) philosophy has taken root because of the wildly fluctuating and increasing prices (much to the dismay of boat refurbishing companies).

Paint companies have responded to the DIY demands by simplifying paint systems that provide glossy finishes and decent durability. One-part modified alkyd enamels, urethanes, and two-part simple mix products line marina supply and big box store shelves. If properly applied, the aesthetics are excellent. With some routine maintenance, durability is good enough.

In addition to aesthetics and durability, ease of application is a prime consideration of the DIY consumer. Of course, while the roll-and-tip finish will never rival a PRO-sprayed finish, the results from today’s formulations can be very good.

Several of these formulations generate little sagging and dripping, which is the bane of�� improperly applied high-end coatings. The caveat is that the instructions for surface preparation must be carefully followed, the owner has a modicum of sanding and buffing skill with the requisite amount of patience. Boat refurbishing companies hide their grins when someone comes in for a full paint repair because they “knew how to paint and didn’t need directions.”

In fact, many PROs that mentor DIY novices suggest first painting oars with the paint system that will be used on the boat hull. This provides insight into the behavior of the paint and more importantly, the actual skill and ability of the painter.

The chemistries used to either commercially or DIY paint new or refurbished boats include alkyds, epoxies, and polyurethanes for interior and exterior surfaces. Table 1 provides the typical paint systems used for various boat locations with the projected maintenance intervals.

Powder Coatings

Powder coatings are used in a huge variety of applications, including boating and marine equipment. These types of coatings are not as widely used as liquid systems, primarily because they are more difficult, if not impossible to repair without completely removing the existing coating. However, there are some advantages to using powder coatings on metal surfaces—particularly for ladders, stairs, rails, flag poles, and such items. Metal, unlike fiberglass or wood, tends to corrode if there is a poor barrier layer between the surface and the environment. The higher powder coating film thickness, together with complete coverage, provides this advantage.

Salt particles are highly corrosive to common powder coatings. If not formulated specifically for marine applications, salt will permeate the coating over time, causing it to powder and break down. Marine powder coatings are typically made from specialized resins and additives that provide for durability, flexibility, water resistance, UV resistance, and even antifouling properties. In addition, these powders use different media—glass beads, coarse and medium sand, etc.—to generate a variety of textures. Powder coatings also have good chemical resistance to most of the types of exposures that boats can encounter even in relatively clean water.

Powder coatings can be applied to a wide variety of substrates, which helps in reducing corrosion on the metal parts throughout the boat. Epoxy and modified epoxy powder coatings are the oldest and still most widely used for this application. They are considered to be “surface tolerant” by many repair shops because of good adhesion to minimally prepared surfaces.² Many South Florida boat owners choose powder coatings for their metal boat parts because the surfaces maintain their luster and shine without needing constant attention.

Other structures located at or very near the coast or off-shore also benefit from powder coatings. Reliability and durability are critical for metal structures that are exposed constantly to the environmental attack of seaspray, humidity, and sunlight. Powder coatings used for these applications provide protection from these elements.

These coatings are governed by standards such as ISO 12944-5:2019. This standard lists environment classifications and provides guidance as to the types of coatings that have been proven to perform well within those boundaries. Suggestions for testing are also provided. Powder coating chemistries and film thicknesses for metal on boats, shoreline, near shoreline, and sea structures are part of this standard.

Rigorous accelerated and real-time cyclic testing has verified long term durability, corrosion resistance and extended surface aesthetics for marine applications. Marine powder coatings must perform well in Corrosion Classification C5M–Very High Marine, which encompasses on shore and offshore areas of high salinity. Buildings in this classification are almost always subjected to constant condensation and high environmental salt contamination as well.³

Typical accelerated testing for marine products includes ASTM G85 Salt Spray and Salt Fog Testing: Annex 1—Acetic Acid Salt Spray Test (non-cyclic) or Annex 3–Seawater Acidified Test (cyclic).

In addition, real-world testing is also required in order to ensure that the corrosion mechanisms are not artificially test-induced, but actually occur in the ascribed environment. Florida exposure testing includes 72 hours of accelerated UV exposure, 72 hours of neutral salt spray exposure, and 24 hours low temperature testing at -20 °C. This cycle is repeated 25 times (4,200 hours) to ensure that the paint systems on metal substrates ultimately exhibit the necessary durability.⁴

Deck Coatings

A necessary safety feature on boats is a skid-resistant deck. No boat owner wants to take the chance that a purported non-skid deck paint loses gripping power and someone ends up overboard. The substrate determines the decision to prime the deck surface. If the deck is wood or bare metal, a primer is crucial. If the deck is wood, a sealer is required. The best primer is a 2K epoxy because it provides more durability and hardness than a one-part system.

The easiest topcoats to apply are one-part paints containing non-skid additives—with the caveat that they be mixed well for an even application. The 2K linear polyurethanes will last longer and stay cleaner than textured paints or one-part coatings. For higher-end paints to perform better, more care must be taken during application. Professional boat refurbishing shops will generally spray-apply polyurethane. Following the application of the textured layer, multiple thin coats are applied to seal the surface. The 2K linear polyurethanes last at least five years and, in the right environmental conditions (rainy and cloudy versus constant sunshine) can provide good service for up to 10 years.

Wood Coatings

Aluminum is taking over as the preferred mast material for modern sailors. But many classic boat owners, traditionalists, and boat enthusiasts love the aesthetics of a wooden mast—even though it requires much shorter maintenance intervals than all other topside paints. Most topside wood paints lose gloss, color, and durability after only two years—but every sailor should check the mast every year. Furthermore, because masts, spars, and tillers see the most banging of any wood component on a boat, chip- and abrasion-resistance are also important coating characteristics. In fact, clear coatings are preferred on masts because cracks, fungus, wood rot, dings, and chips are visible very early—helping to avoid significant damage or a sailing disaster. Paint tends to hide cracks and seams where water can penetrate, causing unseen deterioration due to moisture ingress. These spar varnishes also tend to be soft and flexible, adapting to the expansion and contraction due to hot, dry, cool, and wet weather cycles without cracking.⁵

There is a one-part, self-crosslinked system with outstanding weathering properties. It is safe for application both above and below deck because there is virtually no odor, it has low VOCs, and it is non-toxic. It contains three UV-stabilizers, does not yellow, and is mold and mildew resistant. It flexes with the wood to prevent cracking—providing longer durability. The formulation allows for cleanup using only water.⁶ Heightened consumer environmental awareness, especially relating to waterways, will spur coatings developers to make more environmentally compatible coatings available in the future.

Topside coatings are a very well-developed genre of marine coatings because serious boat owners understand that the eye-catching, gleaming appearance of a well-maintained boat is really a beautiful cover for a tough preservation imperative for long-lasting enjoyment in the ironically corrosive environment of beautiful lakes and seas.

References

1. Awlgrip website. “1973—From Planes to Boats.” https://www.awlgrip.com/fiftyyears/1973-from-planes-to-boats (accessed September 12, 2023).
2. Coatings Systems Inc. Benefits of Marine Powder Coatings for Boats. November 20, 2017.
3. International Standards Organization. 2019. ISO 12944-5:2019 Paints and varnishes—Corrosion protection of steel structures by protective paint systems—Part 5: Protective paint systems.
4. Northpoint Ltd website. Anti Corrosion. “What Is Marine Grade Powder Coating?”�� https://www.northpoint.ltd.uk/2021/08/26/what-is-marine-grade-powder-coating/ (accessed September 24, 2023).
5. The Wood Whisperer.�� “Difference Between Spar Varnish and Regular Varnish?” October 20, 2008.

By Cynthia A. Gosselin, Ph.D., The ChemQuest Group

In 2022, marine coatings were an $8.7 billion market, with a growth projection of 5–7% through 2028.¹ However, there is a lot more to marine coatings than great aesthetics. At approximately a 64% share, anti-fouling/fouling release coatings were the largest portion of the marine coating market, followed by anti-corrosion and self-cleaning/self-polishing coatings. In addition, marine coatings have special and specific functionalities to protect watercraft above and below the waterline. Finally, marine coatings are specially formulated to be easily cleaned.

The two most significant drivers for the growth of the marine coatings market are transportation of goods by sea and recreational sailing. Unlike relatively new, speedy, expensive air shipping, transportation of goods by sea is a centuries-old tradition. To this day, it remains the preferred method for heavy or bulk products. Interestingly, it is also the most cost effective and it tends to have a lower carbon footprint and emission standards. Additionally, safe harbors are widely available almost everywhere there is water, making it a practical and accessible choice.

Recreational or leisure boating is the second largest driver of the marine coatings market. Whether for routine maintenance, hull cleaning, racing efficiency, fuel economy, or craft longevity, marine coatings are top-of-mind for large- and small-craft owners. In both the shipping and recreational categories, shipbuilding and repair are enjoying a resurgence in the post-COVID market.

With all these factors contributing to the growing demand for marine coatings, it’s essential to understand what they are and why they’re so vital. Simply put, marine coatings are broadly defined as waterproof protective layers that are applied to surfaces exposed to or immersed in fresh, brackish, or saltwater. Boats, ships, ferries, small watercraft, and marine structures such as offshore oil rigs and bridge structures employ some kind of marine coating both above and below the waterline.

A wide variety of coating chemistries can be used depending upon the specific substrate and service application, with the exception of unsaturated polyester resin (the type often used in fiberglass). Most marine coatings contain varying degrees of volatile organic compounds and can be applied by brush, spray, roller, or any other convenient method.²

Topside boat paints are usually 1K or 2K polyurethanes, buffable 2K polyurethanes, or alkyd marine enamels that protect the boat from UV damage. Bottom boat paints are antifouling coatings designed to reduce the attachment of aquatic organisms to the hull. Bottom paints include ablative and hard coat paints as well as primers. These types of coatings are best removed with paint removers especially designed for these chemistries.

The inability to escape the effects of biofouling beneath the waterline is one of the main reasons for the strength of the antifouling paint sector. Many boats and ships sat idle during the COVID-19 pandemic and exacerbated the problem, especially in relatively still, warm waters. Sitting idle in the harbor allowed the bottom of watercraft to accumulate barnacles, tube worms, algae, sea squirts, and slime.³ While this is a natural aquatic process, it is one of the most significant hurdles for boat and ship owners alike—particularly when speed and fuel economy are compromised. The commercial reason for using antifouling paints is for improving the flow of water passing the hull, and thereby maximizing fuel economy.

When a hull is covered by only 10% barnacle fouling, 36% more power from the engine is required to maintain the same speed through the water and could be responsible for 110 million tons/year of excess carbon emissions and $6 billion of addition fuel cost in the international shipping industry.⁴

Even recreational sailing is affected. Tapio Lehtinen was racing the 2019 Golden Globe non-stop, around-the-world race when he was almost stopped dead in the water. Racing furiously with his rival, he surprisingly noticed that he was being left behind. Thinking something had happened to his propellor, he dived in to check. To his dismay, barnacles were growing all over the hull. He did finish the race, but 110 days behind the winner. Barnacles had encrusted the entire bottom of the hull, stealing his speed. More had colonized on his self-steering blade, causing it to shear off when the load became too massive.⁵ Whether recreational or commercial enterprises, billions of dollars are spent every year to increase the usefulness, fuel economy, and longevity of watercraft by reducing biofouling.

Besides the economic and convenience factors, biofouling presents another important ecological concern. Marine life hitchhiking along the bottom of a boat can be the mechanism for translocating invasive species to the wrong ecosystem, far from natural predators.

Striped zebra mussels are a species native to the Caspian and Black Seas of Russia and Ukraine that have been distributed by ships as invasive species in Ireland, Italy, Sweden, Spain, the United Kingdom, and the United States. Root-like threads of protein called “byssal threads,” enable the zebra mussels to adhere very tightly to hard surfaces (like boat hulls, native mussels, and rocks). They colonize rapidly in the absence of natural predators, filter out algae needed by the “locals,” and are the succubus that attaches to and incapacitates native mussels. The zebra mussels form dense clusters that cut off water flow, clog pipes, and damage equipment. Their sharp edges can injure swimmers, and the infestation may lead to the devaluation of the boat. Since the 1980s, the Great Lakes in the United States have been struggling to eliminate this nuisance that just came along for the ride.⁶

Because of all the ship and yacht traffic, the Mediterranean Sea has more than 800 identified invasive species. In one audit of leisure vessels sailing through that area, 71% of leisure vessels were harboring at least one non-native species.⁷

Despite the problems plaguing biofouling of hulls, the landscape for marine coatings is moving toward sustainability measures and stricter environmental regulations. Copper-based, biocide-boosted antifouling paints have been the dominant performers in reducing biofouling. However, the effect of these paints does not segregate itself to affecting only those aquatic hitchhikers that attach themselves to the hull. Rather, cuprous oxides carrying biocides leach into the water, where they ultimately settle at the bottom of the sea or lake, also poisoning oysters, welk, clams, and other bottom-dwelling organisms.

Marine coatings manufacturers are now emphasizing improved sustainability along with operational performance factors of reduced power demand, lower fuel consumption, and carbon emissions. Manufacturers have had to become more cognizant of the environmental effects of biofouling agents because of the push by the regulatory agencies resulting from harbor contamination studies conducted during pandemic idle time.

Earlier, paints that contained the organitin biocide tributyltin (TBT) were banned on January 1, 2008, by the International Maritime Organization. For more than 40 years, TBT had been used successfully to boost the performance of cuprous oxide through controlled release. The problem with this effective method was that TBT would leach out of the paint, damaging the aquatic hitchhikers and contaminating the surrounding water. Once there, it would accumulate at the bottom, affecting the endocrine systems of shellfish. This led to abnormal developments, such as female snails taking on male sex characteristics, and severe deformities in oyster shells, making some beds almost extinct.

Since the TBT biocide ban, the number of effective biocides that meet regulatory requirements has decreased substantially. As a result, self-polishing copolymers (SPC), controlled depletion polymers (CPD), and foul release (FR) coatings are gaining popularity. Right now, the biocides in SPC and CPD are evenly dispersed in the matrix and not bound to anything. Release occurs when the matrix erodes (polishes) or by dissolution when water penetrates the paint film. These reactions are relatively uncontrolled and could lead to premature dissolution or over-leaching. Research is underway to find a way to attach the biocide molecules to a polymer carrier. Using hydrolysable covalent bonds could control the release rate of the antifouling constituents— mimicking the long-lived controlled performance of TBT.³

It is clear that a totally different strategy will be needed in the future to satisfy ultimate environmental concerns and regulations in harmony with antifouling performance characteristics. On the one hand, something is needed that will keep marine organisms from damaging and compromising marine craft below the waterline. On the other hand, even the most hardened industrialist agrees that the solution must keep from damaging everything else in its wake.

Nanotechnology that mimics the surface texture of algae that inhibits attachment of marine organisms is one outside-the-box thought. But this is still in the research stage and not yet available for mass production.⁸

There is one other approach that uses a totally different point of view and has proven commercially and environmentally successful. Ninety studies have been completed that pass the EU regulation Biocides Product Directive 98/8/EC (BPD) governing “biocides.” Regulating bodies in Japan (CSCL and JPMA), Korea (NIER), and China (MEP, Order 7) have also approved this material, and notifications have been provided to other relevant shipping regions.

Rather than using the typical paradigm of killing off the barnacle hitchhiker (and ultimately everything in the vicinity), an attempt was made to modify the attachment mechanism of the larvae.

Instead of using metal oxide biocides, medetomidine, a mammal anesthetic, was added to bottom paint. When exposed to medetomidine leaching out from a wet coating, the cyprid larvae of the barnacle species Balanus improvises were repelled from the surface. How? Medetomidine in tiny concentrations stimulates a receptor in the larvae causing hyperactive swimming behavior. Instead of settling down on the surface, the legs move at 100 kicks/minute, forcing it to swim away from the bottom of the boat. The effect is reversible. As the barnacle larvae move away, the kicking stops. This makes it impossible for the organism to attach to the surface.⁹

Since 2016, a thousand governing-body-approved commercial ship applications of this “biocide” were used successfully in several different biofouling paint formulations. This may be the first marriage of true environmental sustainability through benign influence on organisms and the desired performance from an antifouling marine paint.

About the Author

Cynthia A. Gosselin, Ph.D., is director at The ChemQuest Group, ChemQuest Technology Institute, ChemQuest Powder Coating Research. Email: cgosselin@chemquest.com.

References

1. IMARC Impactful Insights. “Antifouling Paints and Coatings Market: Global Industry Trends, Share, Size, Growth, Opportunity and Forecast 2023-2028.”
2. “Marine Coatings Selection Guide: Types, Features, Applications | GlobalSpec.” https://www.globalspec. com/learnmore/materials_chemicals_ adhesives/industrial_coatings_ sealants/marine_coatings#.
3. Koch, S. “Invasive Zebra Mussels.” National Park Service, April 2, 2021. https://www.nps.gov/articles/ zebra-mussels.htm (accessed July 27, 2023).
4. “Sustainable Antifouling by Controlled Release from Polymer-Bound Selektope.” ITECH-Technical-Paper_ November-2022-1.pdf, November 2022, selektope.com (accessed July 27, 2023).
5. Strickland, K. “Tapio Lehtinen’s Barnacle Blight.” Yachting Monthly, May 22, 2019.
6. “The 5 Most Common Marine Fouling Organisms and the Effect They Can Have on Your Boat.” Electronic Fouling Control, Antifouling Tips, June 21, 2023.
7. Rotter, A.; et al. “Non-indigenous Species in the Mediterranean Sea: Turning from Pest to Source by Developing the 8Rs Model, a New Paradigm in Pollution Mitigation.” Front. Mar. Sci., 2020, 7, Marine Pollution Section, March 24, 2020.
8. Kumar, S.; et al. “Nanocoating is a New Way for Biofouling Prevention.” Front. Nanotechnol., 2021, Environmental Nanotechnology Section, Nov. 22, 2021.
9. “About Selektope® – A Sustainable Biocide Used in Antifouling Coatings.” https://selektope.com/ about-selektope/ (accessed July 27, 2023). When exposed to medetomidine leaching out from a wet coating, the cyprid larvae of the barnacle species Balanus improvises were repelled from the surface.

I’m going to get a little personal in this column and take the opportunity to recount my illustrious career in the powder coating industry. I got my start in powder coatings in March 1978. This was before computers, digital scales, Excel spreadsheets, email, and smart phones. Interestingly, even though the tools to develop coating technology continuously evolve, the fundamentals of formulating a high-performance powder coating really haven’t changed that much.

The Beginning

I had just celebrated my 20th birthday, still too young to legally purchase a bottle of wine but filled with an eager enthusiasm to conquer the challenges facing this fledgling industry. Powder coatings were conceived in the mid-1950s as a laboratory curiosity by Dr. Erwin Gemmer, a German scientist. By the 1970s, this technology had found a commercial home as a thick-film, functional coating used to protect pipelines, steel rebar, and electrical equipment. The late 1960s and ’70s ushered in thermoset polymers, the use of extrusion to compound formulas, and electrostatic spray techniques capable of applying relatively thin films.

My inauspicious entry into the industry paralleled powder’s introduction to the major appliance and automotive industries where high performance was required. Typical applications were dryer drums; washer tops and lids; and automotive suspension springs, battery trays, and other under-hood components. I entered the industry as a lab technician at The Glidden Paint Co.’s Research Center in Strongsville, OH, in a maelstrom of fervent product development. At the time, I was laser focused on meeting the coating requirements of a rapidly growing number of enterprising fabricators who recognized the advantages of replacing porcelain enamels and solventborne paints with this groundbreaking finishing technology.

Moving On Up

I completed my chemistry degree four years into my budding career, which vaulted me onto the corporate ladder and provided a path to laboratory project leader and eventually group leader roles. These were dizzying times for the powder coating community. Each year promised double-digit growth of greater than 20%, along with a mind-blowing array of technical dragons to slay and processing mountains to scale.

The powder industry was on fire throughout the 1980s and, even more so, the 1990s. Tier-one automotive suppliers introduced clear polyester powders as the topcoat for aluminum alloy wheels. Automakers installed dozens of finishing systems that utilized powder as a body coat, initially as an intermediate coat (i.e., a primer surfacer), and eventually as the clear topcoat for BMW’s 5 and 7 series cars manufactured in Germany. Concurrently, clever chemists invented low-temperature-cure technologies, including the world’s first UV-curable powder coatings for application to pre-assembled electric motors. Seemingly everything metal that could fit into a cure oven was now being powder coated.

At this juncture, the large multinational paint makers began to realize that powder coatings were here to stay and entered the fray by building their own powder businesses, along with unrelenting acquisition of already-established powder businesses. Glidden, where I spent the first 15 years of my career, was purchased by the UK-based ICI Paints, making it a global powerhouse. This development afforded me the opportunity for a two-year assignment as part of a pan-

European powder group located in Birmingham, England. Upon my return to the United States, ICI sold off most of its industrial coatings businesses, including the powder coating group. I left the day Ferro Corp. bought our powder business to join the Herberts Group, a Germany-based powder producer.

Branching Out

After 19 years toiling away at these two global paint titans, I transitioned into an entrepreneurial realm, initially as an independent consultant and soon thereafter as a small business owner. Since making the break with the corporate world, I have owned two custom powder manufacturing businesses, served as an editor to a few coatings publications, and in 2007 founded the Powder Coating Research Group.

Probably one of my most unintentional but consequential decisions occurred around the turn of the century when I was asked to author a regular Q&A column for a company newsletter. My colleagues at the time suggested the column to be titled “Ask Kevin.” I thought such a humdrum title would attract few, if any, readers and offered in its stead an alternate nom de plume and hence, “Joe Powder” was born. My real name was not attached to the column for the first few years, which created a swirl of intrigue in our staid industry. Through the years, the “Ask Joe Powder” column has appeared on three continents in 10 different publications. In 2020, the Ask Joe Powder “powdcast” debuted and can be accessed through most popular podcast services and on the ChemQuest website, chemquest.com.

The timing of my career moves may not have been stellar, as nearly every time I made a major transition an economic storm was brewing. When I shed my corporate identity in the late 1990s, the powder industry was enduring monumental headwinds with the economic recession of 2000–2001, along with issues with production overcapacity, consolidation, shrinking profit margins, and globalization.

Later that decade, I launched my powder technology group, unbeknownst that the Great Recession was looming in the shadows. Throughout this period, paint companies were tightening their spending budgets, including reductions in R&D, which probably benefitted our technology start-up by providing opportunities where understaffed technical groups couldn’t cover all the organization’s innovation objectives.

I weathered these storms undaunted and continued to thrive, leading an entrepreneurial technology outpost dedicated to crafting the next generations of powder coating technology. In 2021, our business was acquired by The ChemQuest Group, which broadened our resources and expanded our capacity, building a strong platform for future growth.

I recently handed over the reins of our powder coating R&D enterprise to my colleague, Nathan Biller, and the erudite team at ChemQuest. While I have stepped down from full-time employment after 45 exciting years as a technologist in this amazing industry, I won’t disappear any time soon as I will continue consulting work, as well as writing, teaching, and other engagements in the industry.

Future Developments

My rear-view mirror captures an exceptionally rewarding experience in a dynamic industry. Throughout my career, I have collaborated with some of the most ingenious technologists and, most importantly, some of the finest human beings I have ever met. It has been an honor and a privilege to share in the triumphs of this extraordinary technology, and I am enthusiastic to continue to contribute to its bright future.

Kevin Biller, founder of the former Powder Coating Research Group, serves as director of ChemQuest Powder Coating Research. Email: kbiller@chemquest.com.

Chemistry is once again taking a front seat in the quest to find ways to manufacture new, green, people-friendly, sustainable, multifunctional complex molecules for an array of practical implementations.

One method highlighted in this resurgence uses drop-in building blocks to provide a faster way to integrate biomass feedstocks without the need to drastically change high capital investment production processes. However, many of these monomers require UV light, oxygen, and renewable raw materials to provide more sustainable manufacturing and broader flexibility into a wide variety of markets.

While considered a positive leap forward, even this LEGO-like approach to “wrangling molecules” has side effects that do not always move chemical reactions or material properties into the desired manifestations. Unintended byproducts and surprise reactions between the wrong molecules often impede the formation of the desired product. Add to these issues the complexity of inefficient multistep reactions, all of which must be forced into a precise order, and watch many promising endeavors die on the vine. Chemical complexity demands large amounts of human and monetary resources usually not allocated for long-term research.

The ideal reaction would be one that is flexible, quick, reacts independently of added incentives (heat, UV, etc.), does not interfere with other constituent molecules, and still provides the desired effect. The answer to this wish list could well be click chemistry.

Around 2001, shortly after winning his first Nobel Prize in chemistry, Karl Barry Sharpless coined the concept of click chemistry—a new minimalistic approach to molecular formation. He argued that it was somewhat fruitless in trying to imitate the creation of natural molecules (the basis of chemical reactions for all time) because their construction was too inefficient and difficult to master. Rather, Sharpless defined a functional form of chemistry in which building blocks snap together quickly and efficiently. The key to success was to bypass the need to artificially force resisting carbon atoms from different molecules to form bonds with each other. The big problem, aside from difficulty, was that artificially activating these reactions led to unwanted bonds and side reactions that devoured much of the material. Consequently, very little useful product was often generated from these complex, expensive reactions.

Around the same time, Morten Meldal independently discovered what is now known as the crown jewel of click chemistry: the copper-catalyzed azide-alkyne cycloaddition.¹ This reaction is now used globally to link molecules together in a wide variety of product disciplines. Figure 1 presents a visual schematic for one of the most prolific and clean reactions in click chemistry.

Figure 1—Copper ions added to azides and alkynes allow for one of the most efficient reactions within click chemistry.¹

Ironically, this groundbreaking reaction was a happy accident. While trying to run a routine reaction with an alkyne and an acyl halide using some copper and palladium for catalysis, it was discovered that the alkyne reacted to the wrong end of the acyl halide molecule. Further, copper ions controlled the reaction so that only one substance was formed. Even the acyl halide, which should have bonded to the alkyne, remained untouched. What actually happened was that the azide reacted with the alkyne to create a ring-shaped triazole, as shown in Figure 1.

This was a huge deal because triazoles are very stable and found in dyes, agricultural chemicals, and pharmaceuticals. Trying to create triazoles “from scratch” led to unwanted byproducts and significant material waste. This new click reaction was further found to bond together numerous different molecules in a diverse assortment of product disciplines.

To date, the most numerous advancements in click chemistry have occurred within in the pharmaceutical and medical industries. These disciplines are well funded and are always looking for new, more efficient and less invasive ways to treat a range of illnesses—including cancer—while endeavoring to generate fewer side effects.
Most recently, Carolyn Bertozzi developed bioorthogonal reactions in living organisms by taking advantage of strain-promoted alkyneazide cycloadditions to track glycans. This was a further breakthrough in the relatively new science of click chemistry. The copper-catalyzed reaction mentioned earlier as the crown jewel of click chemistry is toxic in living organisms—so it cannot be used for treatment reactions.

First, she modified the Staudinger reaction by connecting a fluorescent molecule to the azide introduced to the cell glycans without adversely affecting cells. Next, she took advantage of the 1961 fact that azides and alkynes can react explosively without the help of copper if forced into ring-shaped structures. This strain-promoted alkyne-azide clycloaddition is now used to map cell functionality without disturbing normal cell chemistry. This work is leading researchers to explore targeted cancer treatments that shut down the ability of the tumor to protect it from a human immune system. This is done by joining a glycan-specific antibody to enzymes that break down those protective glycans on a tumor surface. Clinical trials are currently underway, and if successful, represent a huge stride in the quest to cure cancer.

The main objective in click chemistry is function. Success means that a wide variety of material disciplines can utilize molecular chemical interactions and manipulate optimization of useful properties. Twenty-three years after the breakthrough by Sharpless and colleagues, click chemistry is gaining a strong foothold in the development and, more importantly, adoption within those materials. And everything is not necessarily new—but rather, a revisiting of old chemicals and processes that have been found to be useful in metal-free click reactions that are now compatible with biological systems.

The second objective for click chemistry is to make reactions “easy to do” for all the disciplines where researchers are not trained as chemists. This means that “clicking” is beneficial for many applications beyond physics, chemistry, biology, material, and polymer science.²

As click chemistry evolves, more and more researchers— and even highly sophisticated chemists—are content to leave the carbon-carbon linkage formation to Mother Nature. Rather, similar to the glycan work performed by Bertozzi, it is more useful to focus on much quicker and easier reactions than those that nature uses infrequently. The structures that we, through click chemistry, can form by opening aziridines and epoxides are novel concepts—and the assembly sequence could be more than one such reaction. This is essentially what Bertozzi did with her strain-promoted alkyneazide clycloadditions.

Another very clever property of click chemistry reactions is the ability to disconnect the reaction on command. This is known as “clip chemistry” because breaking bonds can be just as important as forming them.³

Edging closer to the coatings front, significant work has been done with reaction sequences for epoxide ring-openings with hydrazine and subsequent condensation with ß-dicarbonyls or other bis-electrophiles to generate an enormous range of heterocyclic structures for potential reactions. Library synthesis of these molecules is highly efficient, providing a wide base of potentially compatible reactants. A huge diversity within the large, available pool of epoxides gives researchers wide latitude in selecting reactions for material modification, improvement, and customization.⁴

Coatings offer an attractive area of interest for click chemistry, particularly with myriad almost-contradictory objectives of cost reduction, greener technologies, and greater durability. In 2008, click chemistry began synthesizing linear polyurethanes (PU) with alkyne groups located on the backbone by reacting two different alkyne-functionalized diols (PDM and DPPD) with a diisocyanate compound.⁵

These PUs generated multiple “clickable” functions that resulted in high thermal stability and improved char yield that was proportional to the alkyne content without interfering with the basic PU chemistry. If making use of readily available azide compounds continues to be successful, universal functionalized PU will generate new classes of PU coatings with easily adaptable physical properties.⁵

Next, the Huisgen 1,3-dipolar cycloaddition was used by reacting these alkyne functionalized materials with several azide compounds in the presence of a copper catalyst. The successful click reaction with BzN3 allowed amine and difluorinated compounds to attach to PU leading to good yields and new functionalities in the side-chains attached to the backbone.

Click chemistry offers many advantages for the modification of biomaterials, surfaces, particles, and organic compounds. Those advantages include: broad applications, modularity, mild reaction conditions, reliability of both small- and large-scale reactions, high yields, little to no need for purification, inoffensive byproduct generation that is highly desirable in green technologies, and compatibility with living systems for targeted cell treatments.

Out of the nine different types of click reactions, three are most heavily used in biomaterials from simple biolabeling and detection to advanced Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) applications.

The top nine current applications taking advantage of click chemistry include: Biomolecule labeling and detection, solid and solution phase biomolecule modification/ligation, construction of analog compound libraries, in situ click chemistry for drug lead discovery, drug delivery, material optimization— particularly modification of polymers, probes for viral studies, CRISPR sgRNA synthesis, and target gene labelling and novel applications including “click to release.”⁶

In 2016, click chemistry was introduced into waterborne systems as a crosslinking strategy using reactions between copper sulfate and sodium L-ascorbate (Figure 2).⁷ These coatings exhibited films with significantly improved tensile strength, hardness, adhesion strength, water resistance, and solvent resistance as compared to traditional water-based polyurethane coatings.

Figure 2—Click crosslinking reaction in water-based polyurethane coatings.⁷

These click chemistries as alternatives to other available crosslinking strategies are not only broadly applicable to PU chemistries, but also to polyester dispersions and polyacrylate emulsions— without generating small molecule byproducts. Selfcrosslinking systems based on N-methylolacrylamide, pendent acetoacetate groups and reversible keto-hydrazide reactions cannot be applied universally to all three polymer systems.⁷

It also appears that those improved film properties can be achieved through click crosslinking without the need for traditional hardeners. The ability to eliminate components and additives in paint systems without damaging physical properties has the potential to reduce costs and counteract supply chain issues when manufacturing industrial coating applications.

Sharpless, Meldal, and Bertozzi shared the 2022 Nobel Prize in Chemistry for laying the foundations of click chemistry and bringing chemistry into an era of true functionalism. The discoveries were elegant, clever, and novel, and have given rise to applications that are useful— the latter adjective being the most important outcome for two-time Nobel Prize winner, Karl Barry Sharpless.

Cynthia A. Gosselin, Ph.D., is director at The ChemQuest Group, ChemQuest Technology Institute, ChemQuest Powder Coating Research; . Email: cgosselin@chemquest.com.

References
1. Fernholm, Ann. Their Functional Chemistry Works Wonders. The Royal Swedish Academy of Sciences. The Nobel Prize in Chemistry 2022.
2. Castelvecci, D. and Ledford, H. Chemists Who invented Revolutionary ‘Click’ Reactions Win Nobel. Nature 610, 242-243 (2022).
3. Devaraj, Neal K. and Finn, M. G. Introduction: Click Chemistry. Chem. Rev. 2021, 121, 6697–6698.
4. Sharpless, K. B., et.al. Click Chemistry: Diverse Chemical Function From a Few Good Reactions. Agnew. Chem. Int. Ed. 2001, 40, 2004–2021.
5. Fournier, D., and Du Prez, Philip. “Click” Chemistry as a Promising Tool for Side-Chain Functionalization of Polyurethanes. Department of Organic Chemistry, Polymer Research Group, Ghent University. May 1, 2008.
6. The Top 9 Click Chemistry Life Science Applications You Need to Know. J&K Scientific LLC website. https:// www.jk-sci.com/blogs/resourcecenter/ the-top-9-click-chemistry-lifescience- applications-you-need-toknow. Accessed January 20, 2023.
7. Hu, Jianging, et.al. Click Cross-Linking- Improved Waterborne Polymers for Environment-Friendly Coatings and Adhesives. ACS Applied Material Interfaces, 2016, 8, 27, 17499–17510.

As the Waterborne Symposium celebrates its 50th year presenting the latest in coatings technology, I was asked by the CoatingsTech editor to reflect on how the conference has influenced our industry over the years.

In 1981, I was hired as a chemist for Thompson-Formby, Inc. in Olive Branch, MS, and was responsible for the Thompson’s© Water Seal© brand. I had little experience in formulating coatings as a trained biochemist, so my journey began with learning all I could about the coatings business. In the early 1980s, all eyes were focused on addressing the upcoming California reductions in volatile organic compounds (VOC) in architectural coatings. Reducing VOCs was the primary challenge in the industry and the Waterborne Symposium, and its close association with the highly regarded School of Polymer Science and Engineering at the University of Southern Mississippi (USM) provided a forum for discussing this issue. In a time of no internet, attending conferences and reading published works was the only way to find new advancements in polymer research.

In 1983, I attended my first Waterborne Symposium to learn the latest in the new technologies and chemistries that all of us needed to help address the difficult task of lowering VOCs while maintaining performance. The language of polymer science was new to me, but the high-quality presentations helped me understand how the puzzle pieces went together. As time passed, more air quality regulations were imposed in the United States and then in Europe, and continuing reductions in VOCs created new problems with coatings characteristics like dry time, lapping, flow and leveling, durability, and wet-edge reduction. New technology was needed, and year after year, the Waterborne Symposium offered information about new resins, improved ways to cure coatings, and new techniques for lowering VOCs. Through the years, the Waterborne Symposium has consistently served as a venue for examining the latest problems. As we enter an era of increased sustainability, more biobased resins, and a reduced fossil-fuel future, the symposium is certain to present the latest technologies to address the needs of the coatings industry.

One of the perks of my position at Thompson-Formby was a close association with Shelby Thames, Ph.D., who, at the time, was the chair of the Polymer Science School at USM. As one of the founding fathers of polymer science and the Waterborne Symposium, his example and high standards have influenced the entire coatings industry by always pushing the boundaries of knowledge and technology. He often came to the Thompson-Formby facility for one-on-one lectures about polymer science and regaled us with stories that brought coatings to life. His influence, guidance, and pure joy of teaching others have influenced me beyond measure. His legacy in polymer science is extraordinary.

As a lifelong learner, I have always considered the Waterborne Symposium necessary to my continued education. The coatings industry has provided me with a fulfilling career, lifelong friends, and a chance to help others just beginning their journey in this business. In the most challenging of times, I hope the Waterborne Symposium continues to thrive and provide value to many other coatings professionals for many years to come.

Victoria Scarborough, Ph.D., is vice president, collaborative innovation, at The ChemQuest Group, Inc., and ChemQuest Technology Institute. Email: vscarborough@chemquest.com and phone: 330-998-5483.

Be sure to check out the entire digital issue of the January-February 2023 CoatingsTech.

Technically speaking, color is simply the retransmission of visible energy that is not absorbed by an object. Visible light is a portion of the electromagnetic spectrum that humans have evolved to see within a frequency range of 400–700 Terahertz. But in its most visceral form, color is energy, universally transcending language and culture.

The Munsell color system (Figure 1) is a color space that identifies color based on three properties: hue (basic color), chroma (color intensity), and value (lightness). It was created by Albert H. Munsell in the early 20th century and adopted by the U.S. Department of Agriculture as an official color system for soil research in the 1930s.

This early work was refined in 1929 and further enhanced in the 1940s, resulting in the modern Munsell Book of Color. The Optical Society of America’s Uniform Color Scales and the CIELAB L*a*b and CIECAM02 color models used in the paint and color industry today were built on the Munsell color system. The original Munsell color chart is still used today to compare computer models of human color vision.¹

Figure 1—Munsell color system: Solid cylindrical coordinates of color.²

The perception of color elicits linguistic and emotional responses that vary across cultures. The human eye perceives millions of differentiated colors. However, human language groups color into much smaller categories. Some primitive languages use as few as three words corresponding to black, white, and red to identify color, while industrialized languages can have as many as 12 language categories comprised of differentiated subsets.

A 2017 MIT study of 100 languages found that the “warm” part of the color spectrum elicits more color words such as orange, yellow, and red compared with “cooler” color regions such as blue and green. In fact, the cooler colors are often identified differently by people using the same language. The premise is that “warmer” colored objects are more easily distinguished—making warm color labels more consistent even across cultures.³ Language universally prefers to bring more color words to warmer parts of the spectrum as opposed to the cooler segments.

Since 1994, there have been a plethora of studies trying to understand emotional response as a function of color. These in-depth studies parsed color to the point of focusing on hue, chroma, and lightness as individual harbingers of emotional response. After much analysis and debate around emotional responses associated with specific colors, hues, physical events, objects, or physical space, the conclusion was that “a color-related emotion is highly dependent on personal preference and one’s past experience with that particular color.”⁴

The real conclusion from all these studies is that color has an inherent psychological effect on the human psyche—it influences mood, energy level, inspiration, and accomplishment. So, it is no surprise that the industry most responsible for generating color has hosted a contest for itself since 2000. The express purpose of the event is to harness one color each year to be THE manifestation of the next year’s forecast as influenced by societal changes, economic and political climates, environmental shifts, and technological and scientific advancements.

Since 2000, the Pantone Color Institute has selected the “Color of the Year.” Trends from all aspects of society are studied throughout the year, considering the collective research generated by traveling observers of culture, nature, and events all over the world.

Pantone’s first selection, a blue hue called Cerulean, was hailed as “the color of the millennium.” The zeitgeist for this selection was the desire for inner peace and fulfillment during uncertainty, yet at the same time, reflecting on the past while looking toward the future promised by the new millennium.

In the first few years, color trend forecasting was interesting and novel—with comparatively few designers taking advantage of these winning colors through 2007. However, between Honeysuckle in 2011 and Tangerine in 2012, Pantone’s Color of the Year took on a life of its own. It was around that time that major paint brands began to participate in earnest.

Today, when a new Color of the Year is announced, Pantone blankets designers with an array of products and color palettes designed around the winner, promulgating huge influence in the world of design and brand marketing. And we should care about which color Pantone selects for Color of the Year because, in effect, all that research centers around what we, as societal people, turn to when we need comfort, inspiration, energy, refreshment, hope, calm, or simply a change. In a sense, we choose the color.

In 2020, the Colors of the Year were earth tones designed to denote safety and grounding. One of the few times that there were two selections for color of the year was in 2021 when rock-solid Ultimate Gray and the cheerful yellow Illuminating were selected. This marriage of color conveyed a strength, resilience, and hopefulness that the executive director of Pantone described as enduring and uplifting—a message of happiness supported by fortitude.

The 2022 colors were cautiously optimistic—primarily in soothing tones of green. Interestingly, Pantone’s 2021 Color of the Year did not follow the green trend and instead introduced a bold periwinkle called Veri-Peri, which was inspired by the increasing time spent in the metaverse.

The color values of each of the 2023 branded color selections mentioned in the article.

In 2023, the kid gloves of uncertainty and isolation finally came off. Warm, nature-inspired hues with tones for nurturing and well-being will offer coziness and comfort. All the 2023 Colors of the Year feed into the desire for comfort, the need for simplicity, and the aching for variety satisfied with colors all over the palette. If there is a green color offering, it is uncharacteristically bold, vibrant, and deep.

Even Etsy joined the party and offered a 2022 Color of the Year. The hyper-stylish Emerald Green was a bright, bold choice in a field of softer sage greens. For 2023, Etsy paired with Sherwin Williams’ Redend, bringing it to life with a curated selection of home accents and accessories.

Robert Kaufman Fabrics announced its first Color of the Year in 2021 with a bright, bold purple called Cosmos. The 2023 Color of the Year will be announced in December, and the excitement is building on the Kona Cotton ordering site frequented by quilters and other textile artisans.

Even RoomMate Décor, the largest manufacturer of wall decals and decorative peel-and-stick products in North America, took advantage of the hype and buzz and announced its own Color of the Year in 2021. Its Green Aloe was a natural, fresh shade of green, leaning into that year’s symbolic trend of growth, healing, optimism, and joy. That was followed by Cream Moonstone in 2022, selecting a versatile neutral that acted as a calming oasis, projecting warmth and softness. No hint yet as to the 2023 RoomMate Décor Color of the Year—the palette choices are so broad.

WGSN and Coloro forecasted Digital Lavendar to be the Pantone Color of the Year for 2023.

NEW YEAR, NEW HUES

The Pantone Color Institute is forecasted to announce Digital Lavender as the 2023 Color of the Year as suggested by WGSN in collaboration with Coloro. This hue nods to the feelings of isolation and the merging lines between the physical and digital world. This purple is slated to take over the fashion world and be very important for consumer electronics, digitized wellness, mood-boosting lighting, and home goods and accents. The sensory quality is perfect for therapeutic self-care and wellness products, peace, and serenity. Research suggests that this color will be readily accepted by all generations and celebrated by Gen Z.^5,6

Since 2011, more and more paint brands have been leaping onto the Color of the Year bandwagon—taking advantage of the increasing publicity generated from the buzz and hype associated with these carefully researched color selections and exquisitely timed announcements.

The 2023 Colors of the Year exhibit a desire for comfort, simplicity and variety. Unlike the overwhelmingly green color selections of 2022, the 2023 offerings are all over the color palette. This year, no one hue trend dominates—yet. From the maximalism of a vivid raspberry to safe minimalist white, there is something for everyone.

AND THE WINNERS ARE …

Figure 2—Palette of the 2023 branded Colors of the Year.

Benjamin Moore: Raspberry Blush

This is a vivid, charismatic, red-orange hue, the lead color in the Color Trends 2023 Palette. Andrea Mango, color marketing and development director at Benjamin Moore, said that the inspiration for this color was that “people are ready to bring color back into the home, taking a step outside their comfort zones.” These confident shades “empower the use of statement colors that deliver delight and personality.” This color is the 2023 height of maximalism and deserves a try on your favorite wall.⁷

Sherwin Williams: Redend Point

Sue Wadden, director of color marketing at Sherwin Williams, stated that this “soulful blush-beige” hue was “inspired by the idea of finding beauty beyond ourselves a heartening hue that invites compassion and connection into any space.” The soulful vigor of this color envelops any room, gives the feeling of a warm hug, and creates feelings of warmth, motivation, and comfort. This color emotes energy, providing confidence and heightening creativity, especially within the social center of the home.⁷

Behr: Blank Canvas

This year, Behr upended the bold color trend by delivering a warm, neutral white to provide a sense of renewal and fresh starts. Blank Canvas is a great neutral, providing a clean feeling throughout the home without being bland, garish, or harsh. The warm undertones feed into the feeling of safety. It can be used within a monochromatic minimalist design or paired with a set of colorful accent pieces, drapes, or furniture.⁸

I’ll admit that these three 2023 Colors of the Year are the ones that “spoke” to me, energizing my mood and heightening creative instincts. The remaining 2023 Colors of the Year (Figure 2) serve to solidify reflections of current trends, as the warm, earthy hues—suitable for softer, cozier spaces—connect us with nature, serenity, and safety (and thankfully, without a hint of pale green). Most importantly, the Color of the Year palette is all about exploring variety. In short: there is something that will resonate with everyone.

Colors of the Year are reminiscent of runway couture—beautiful, striking, rich colors that are poised to become mainstream as they offer consumers, designers, artists, decorators, and fabric and accent pieces a basis for blending beauty and elegance with practicality. It will be interesting to see which of these colors break through and become sought after, and more importantly, timeless.

Cynthia A. Gosselin, Ph.D., is director at The ChemQuest Group/ChemQuest Technology Institute/ChemQuest Powder Coating Research; cgosselin@chemquest.com; www.chemquest.com.

References

1. Ottosson, Björn. A Perceptual Color Space for Image Processing. Blog post, Dec 23, 2020, https://bottosson.github.io/posts/oklab/ (accessed Oct 31, 2022).
2. Munsell 1943 Color Solid Cylindrical Coordinates.png. Wikimedia Commons.
3. Trafton, Ann. Analyzing the Language of Color. MIT News Office. Sept 18, 2017.
4. Kaya, N., and Epps, H. H. Relationship between color and emotion: A study of college students. College Student Journal, 2004; 38(3), 396–405.
5. LeFevre, Camille. Coloro + WGSN 2023 Colour of the Year: Digital Lavender. Midwest Home. Oct 4, 2022.
6. Brama, Shrestha. Digital Lavender Color of the Year. The Fashion Frill. Oct 22, 2022.
7. Buckman, Anna. 2023’s Paint Colors of the Year Offer Something for Everyone. TRZ. Oct 18, 2022.
8. Dohman, Katie. Behr Paint’s Color of the Year 2022 is “Blank Canvas.” Family Handyman. Sept 29, 2022.