Coatings play a crucial role in both protecting and enhancing the appearance of surfaces, thereby extending their service life while maintaining their functionality and visual integrity. Yet, the decision-making process in the coatings industry is frequently dominated by one central question: “What is the cost?” While the cost is undoubtedly a significant consideration during coating development, prioritizing it at the expense of quality and sustainability can have detrimental effects on both short-term and long-term outcomes. Thus, this article aims to guide stakeholders in the coatings industry towards a more informed decision-making process that goes beyond the singular focus on cost.

Enhanced Durability and Reduced Maintenance Costs

From the paint on our walls to the protective coatings on industrial machinery, the quality of coatings significantly influences the longevity and performance of our assets. Opting for high-quality coatings is not just an expense; it’s an investment in the long-term durability and longevity of our possessions. These coatings withstand harsh environmental conditions including corrosive substances, UV radiation, extreme temperatures, abrasion, chemical exposure, humidity, mechanical stress etc., thereby reducing maintenance costs and lowering the environmental footprint associated with frequent replacements. For instance, epoxy resins protect metal surfaces from corrosion, extending the life of structures like bridges and pipelines, while polyurethanes, known for abrasion resistance, minimize wear in high-traffic areas such as industrial floors and conveyer belts. It is imperative to choose the appropriate resin system for the intended end-use so as to benefit and progress economically as well as environmentally.

Reduction and Elimination of VOCs

Coatings are a significant source of volatile organic compounds (VOCs) released into the atmosphere since they incorporate raw materials such as petrochemical solvents and other precursors that are obtained from fossil fuels. Solvent evaporation occurs during the coatings’ curing or drying phase and introduces these VOCs directly into our atmosphere.¹

High solvent content is not only detrimental to the environment but also to business due to the uncertainty in petrochemical price fluctuations. Thus, academic and industrial researchers nowadays focus on employing more environmentally friendly manufacturing techniques that produce less or zero VOCs. The products produced have been shown to have longer shelf lives, consume less energy and/or emit zero or low VOCs when in use, all by utilizing sustainably sourced renewable biobased resources.

The coatings industry, particularly in the architectural coatings sector, has significantly reduced VOC emissions by replacing solvent-borne coatings with water-borne ones. Water-borne coatings, by utilizing water as the primary solvent, present a cost-effective alternative to organic solvents derived from petrochemical sources. This move not only contributes to savings in raw material costs but also helps companies to avoid regulatory penalties associated with VOC emissions, contributing to long-term cost efficiency. Additionally, water-borne coatings often exhibit improved application properties, leading to potential cost savings achieved by reduced drying times, and enhanced coverage. The simplified cleanup process, using water-based solvents, further reduces expenses associated with equipment and cleanup efforts.²

Replacement of Petrochemical Feedstocks with Bio-based Feedstocks.

Another approach towards sustainability is biobased coatings that are developed from renewable resources like plant-based oils or agricultural waste. These substantially contribute to advancing eco-friendly practices by reducing our reliance on finite fossil fuels. The production of biobased coatings often involves locally sourced, renewable materials, potentially reducing transportation costs and lowering the environmental footprint associated with the supply chain. Yet, it is crucial to utilize non-edible sources for biobased polymer production to prevent competition with food resources, ensuring sustainable production practices without compromising the availability and affordability of essential food crops. NSPC’s extensive line of products derived from cashewnut shell liquid are an excellent illustration of this.

Additionally, substituting unique biobased monomers for petrochemical building blocks may also offer unique opportunities to create coatings with novel functionalities and explore unique applications that were challenging to achieve using conventional fossil-based alternatives.  Moreover, as the demand for sustainable products grows, there is a potential for market competitiveness to drive down the cost of biobased coatings. ^3,4

Since the large-scale production of sustainable materials involves significant capital investments and operational costs, a Techno-Economic Analysis (TEA) can help decision-makers in allocating resources effectively and making informed investment decisions. This allows one to evaluate production costs and to determine potential profitability compared with conventional fossil-based materials or other bio-based alternatives. Beyond economic considerations, environmental assessments can be evaluated by performing the Life Cycle environmental impact Assessment (LCA), which enable one to analyze the entire polymer production chain, from raw material sourcing to final product distribution. Combination of both techniques ensures the economic viability as well as the sustainability advantage of biobased polymers in a competitive market.⁵

Energy Efficiency and Material Efficiency

Despite the success of water-borne coatings in architectural coatings, most industrial coatings refrain from using water-borne alternatives since they do not provide sufficient solvent and corrosion resistance. Thus, high-solids coatings technologies are commissioned as they offer an environmentally friendly alternative that minimizes the release of VOCs, effectively balancing the environmental and performance issues. Many of these processes require elevated temperatures for the curing process and, as a result, are not very energy efficient. By investing in high-solids coating techniques, industries can simultaneously decrease reliance on fossil fuels and diminish the carbon emissions associated with energy production.  While the initial investment in adopting these techniques may incur some capital costs, the long-term benefits include significant energy savings and a consequential reduction in operational expenses, making it a financially and environmentally beneficial choice.

Approaches such as 100% solids powder coatings exemplify a material-efficient method, involving the application of a dry powder to a surface, that is subsequently heated to create a uniform, durable film. Little or no volatile organic content, high utilization rates eliminating lengthy drying procedures, high performance, economic advantages, and elimination of hazardous waste makes powder coatings inherently more material-efficient and environmentally friendly compared with traditional liquid coatings. Yet, sometimes excessively high energy is used for film formation (temperatures above 180 °C) which can make this method energy inefficient. Higher temperatures also limit the range of their application to substrates with high thermal resistance. This creates a need for the development of curable powder coatings at room temperature or below.⁶

UV-curable coatings are cured with ultraviolet light and do not require heat or solvents, representing a valuable sustainable choice. This method not only uses less energy but also produces fewer pollutants and shortens curing periods. UV-curing is a “green process,” and nowadays significant attention is drawn to the development of UV-responsive bioderived materials. In comparison to thermally cured powder coatings, UV-curable powder coatings formulated using photoinitiators and additives offer greater benefits such as minimum capital investment, solvent elimination, faster curing, high efficiency, low processing cost and low energy consumption.^7,8

Electrocoating, or E-Coating, stands out as another energy-efficient technique applying paint or coating to a conductive object via an electric current. Known for its efficiency in coating complex shapes with minimal overspray, electrocoating contributes to waste reduction and significant cost savings. The automated nature of electrocoating not only ensures consistent application, reducing the need for manual intervention and leading to labor savings but also results in high-quality finishes that minimize defects. This efficiency in application and superior finish contributes to overall cost savings in the production process in spite of the initial capital expenditure.⁷

Effective Waste Management

Every year, enormous quantities of plastics and plastic-coated materials are manufactured globally. These eventually are introduced into the environment as plastic waste and accumulate in our oceans, which is a major environmental concern. This accumulation poses a substantial threat to marine ecosystems and has far-reaching consequences for the planet’s overall environmental health. Efforts to address the issue of existing plastic waste are crucial, but equally important is the proactive approach of preventing waste accumulation in the future. In response to the environmental challenges posed by plastic waste, there is a growing emphasis on the development of coatings that are either recyclable or biodegradable.

Recyclable coatings can be reprocessed and reused, reducing the demand for new plastic production and thereby minimizing waste. This not only contributes to environmental preservation but also holds the potential for substantial cost savings by avoiding the expenses associated with the production of virgin plastic materials. On the other hand, biodegradable coatings have the capacity to break down naturally over time, mitigating the long-lasting impact of plastics on the environment. While the initial cost of biodegradable coatings may seem to be higher than traditional alternatives, the long-term benefits far outweigh these expenses.⁸

The integration of a “switch” in products, triggering either biodegradation or recycling as their lifecycle concludes, represents an innovative approach with significant industry implications. Additionally, it could contribute to reduced costs associated with waste management and disposal, as the switch-enabled products inherently promote more responsible end-of-life scenarios.⁹

Striking the Balance: Sustainable Decision-Making in Coating Industry

In conclusion, the need of the hour is for industry leaders to make well-informed decisions that not only attain financial goals but also enhance the long-term durability and environmental performance of coated surfaces. Our decisions need to be based on the acceptable levels of compromise that balance performance, price, and sustainability.

The combined benefits of sustainability and superior performance will contribute to an overall cost-effectiveness that extends beyond the initial financial investment for certain newer technologies. The advantages of long-term savings, enhanced performance, and positive environmental impact position sustainable coating technologies and processes as the preferred choice for tomorrow’s green economy.

References

1. Jiménez-López, A. M. & Hincapié-Llanos, G. A. Identification of factors affecting the reduction of VOC emissions in the paint industry: Systematic literature review – SLR. Prog Org Coat 170, (2022).
2. Cunningham, M. F. et al. Future green chemistry and sustainability needs in polymeric coatings. Green Chemistry vol. 21 4919–4926 Preprint at https://doi.org/10.1039/c9gc02462j (2019).
3. Cywar, R. M., Rorrer, N. A., Hoyt, C. B., Beckham, G. T. & Chen, E. Y. X. Bio-based polymers with performance-advantaged properties. Nature Reviews Materials vol. 7 83–103 Preprint at https://doi.org/10.1038/s41578-021-00363-3 (2022).
4. De Jong, E., Higson, A., Walsh, P. & Wellisch, M. Product developments in the bio-based chemicals arena. Biofuels, Bioproducts and Biorefining 6, 606–624 (2012).
5. Wolf, Oliver. et al. Techno-economic feasibility of large-scale production of bio-based polymers in Europe. (Publications Office, 2005).
6. Du, Z. et al. The Review of Powder Coatings. Journal of Materials Science and Chemical Engineering 04, 54–59 (2016).
7. Czachor-Jadacka, D. & Pilch-Pitera, B. Progress in development of UV curable powder coatings. Progress in Organic Coatings vol. 158 Preprint at https://doi.org/10.1016/j.porgcoat.2021.106355 (2021).
8. Fertier, L. et al. The use of renewable feedstock in UV-curable materials-A new age for polymers and green chemistry. Progress in Polymer Science vol. 38 932–962 Preprint at https://doi.org/10.1016/j.progpolymsci.2012.12.002 (2013).
9. Maraveas, C. Production of sustainable and biodegradable polymers from agricultural waste. Polymers vol. 12 Preprint at https://doi.org/10.3390/POLYM12051127 (2020).
10. Garrison, T. F., Murawski, A. & Quirino, R. L. Bio-based polymers with potential for biodegradability. Polymers vol. 8 Preprint at https://doi.org/10.3390/polym8070262 (2016).