Water-based coating technologies have often been viewed negatively, particularly in applications where high performance is required. While this perception may still exist, stricter environmental regulations (such as air quality standards) and the growing emphasis on sustainability have led to the increased use of water-based coatings in the marketplace. As a result, many asset owners, specifiers, and contractors are now considering these coatings for their projects.
Recent developments in water-based coating technologies have alleviated many of the previous concerns associated with their use. In fact, the numerous advantages of these next-generation materials far outweigh the remaining concerns. In this article, we will delve into water-based coatings, how they compare to solvent-based coatings, and how recent advancements are changing the game when it comes to coatings selection.
[Related Webinar: Recent Advances in Water-Based Coatings Technology]
What Are Coatings Made Of?
First, let’s look at coatings in general and their composition so that we can understand water-based coatings a little better. All types of coatings are built from four building blocks:
- Binder: The binder in a coating is the non-volatile part of the liquid components, also known as the vehicle. It is responsible for converting the coating from a liquid into a solid and forming a barrier against water, oxygen, and chemicals. It must also bond well to the substrate and have the desired properties of strength, hardness, and flexibility. Some coatings—such as alkyds, epoxies, and urethanes—are named after their primary binder.
- Pigments: These are solid particles that are added to coatings to give them color, protect against weathering, or assist in corrosion protection. They do not dissolve into the coating’s vehicle.
- Additives: These are liquid additions to coatings that affect their performance, curing, or application properties in some way. They can be used for defoaming, drying, wetting, UV resistance, and more. The exact formula of additives is often a closely guarded secret.
- Solvents: These substances are added to binders so that they can be applied to a substrate. They are not part of the final coating and evaporate after application in a liquid or fluid state. Solvents are judged based on their solvency power (ability to dissolve a given binder) and volatility (rate of evaporation). Chemical solvents are regulated by the U.S. Environmental Protection Agency (EPA) to limit volatile organic compounds (VOC) emissions. More products are being manufactured that use water as a solvent, solvents that are not considered VOCs, or no solvents at all.
In this article, we will be focusing on specifically water-based coatings. Although many people believe that such coatings have limited use, their capabilities have greatly improved in recent years. Pair this with their advantage when used in confined areas and with respect to VOC emissions, and you’ll find that these coatings can be used much more widely than many corrosion industry professionals may be aware of.
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Water-Based Coatings: A Brief History
Water-based coatings have a long history, dating back to ancient times. The Egyptians used water-based paints to decorate their temples and tombs, and the Chinese used water-based lacquers to protect their furniture and other objects. In the 18th and 19th centuries, water-based coatings began to be developed for industrial use. These coatings were typically made from natural materials such as animal glue and casein. However, they were not very durable and were susceptible to moisture and mildew.
In the early 20th century, synthetic binders were developed that made water-based coatings more durable and resistant to moisture. These new binders, such as acrylics and latexes, allowed the coatings to be used in a wider range of applications.
Misconceptions About Water-Based Coatings
Major formulation advancements are challenging misconceptions about what a water-based coating can do or be used for. Below are some examples of these.
Misconception 1: All Water-Based Coatings Are the Same
The assertion that “all water-based coatings are created equal” is incorrect. While these coatings do use water as their primary solvent, there is a significant degree of variation in their composition, performance characteristics, and intended applications.
In fact, today’s water-based coatings represent a new generation of high-performance materials that have been specifically designed to meet the demanding requirements of industrial and commercial applications. Examples of these next-generation products include:
- Inorganic hybrid water-based epoxies: These coatings combine the durability and chemical resistance of epoxies with the low VOC and environmental benefits of water-based systems.
- Waterborne epoxy zinc-rich primers: These primers provide excellent corrosion protection for steel substrates, even in harsh environments.
- Water-based silicone grafted composite exterior finishes: These finishes offer superior durability, weather resistance, and UV protection.
- Self-crosslinking hydrophobic acrylics with dryfall properties: These coatings provide rapid recoatability and excellent resistance to water, making them ideal to use in wet or humid environments.
What these materials have in common is that they have been formulated to provide the highest levels of performance and asset protection. They are designed to meet the specific needs of demanding applications, such as those found in the construction, marine, processing, and manufacturing industries.
Misconception 2: Water-Based Coatings Underperform Compared to Solvent-Based Coatings
The misconception that water-based coatings do not perform as well as solvent-based coatings is gradually being dispelled as confidence in the former’s performance grows with increased use. Market share in water-based coatings continues to grow as a result.
Complete waterborne coating systems are now capable of meeting performance requirements such as ISO 12944 category C4 and C5 for the highest corrosion resistance, which is contributing to their acceptance. Even water-based materials that are approved for use in potable water immersion, such as Tnemec’s Series 1220 HydroLine, are now available on the market.
This was a sector that was previously solely dominated by solvent-based and 100%-solids materials. Additionally, accelerated laboratory testing of these materials reveals that many of these cutting-edge water-based technologies either match or surpass their solvent-based counterparts in terms of performance.
Misconception 3: Water-Based Coatings Carry the Risk of Flash Rust
In recent years, advancements in additive and pigment technology have enabled suppliers of these materials to provide new flash rust inhibitors that exhibit superior performance compared to their predecessors. While flash rusting is a concern in the realm of protective coatings, these advancements have enabled reputable coating manufacturers to formulate their products using these next-generation flash rust inhibitors, which significantly reduce the risk of flash rusting on metal substrates.
For example, all of Tnemec’s water-based steel coatings formulas are formulated to combat flash rusting. In other words, flash rust isn’t something that’s endemic to these kinds of coatings, as new formulations have been designed to address this problem.
Misconception 4: Water-Based Coatings Are More Sensitive to Environmental Conditions
Many people believe that water-based coatings are more sensitive to environmental conditions during application and cure. While this may have been true in the past, significant research has been conducted in recent years to enhance their application and cure in more challenging environmental conditions. Significant advancements have been made in properties such as time-to-moisture resistance and surface tolerance of these materials.
Some of the newer coatings on the market are capable of curing at lower temperatures than their earlier counterparts as well. Tnemec Series 90-75 Tneme-Zinc, for example, has been engineered to cure quickly, making it a good choice for steel surfaces in industrial and marine environments. In fact, a number of Tnemec’s water-based products are engineered to provide a faster cure than previous generations.
Misconception 5: Water-Based Coatings Are Harder to Apply
Enhancements in water-based products now enable application and film-build properties that rival traditional solvent-based coatings. In many instances, water-based materials can actually be easier to apply as they permit application using lower-pressure spray equipment and even by brush and roller. The extended working time of many of these materials facilitates application.
Another crucial factor is that the effective solvent in these materials is water, rather than a potentially volatile or hazardous solvent. This can aid in meeting sustainability goals and significantly contributes to increased worker safety on a job site.
Water-Based vs. Solvent-Based Coatings
As discussed, modern formulations of water-based coatings are increasingly going head-to-head with solvent-based coatings thanks to improved performance and a number of key advantages stemming from their composition. Let’s first take a look at the advantages of water-based coatings:
- They have a lower VOC content than solvent-based coatings, making them more environmentally friendly and safer to use.
- They are easier to clean than solvent-based coatings because they can be cleaned up with water. Solvent-based coatings, on the other hand, require xylene or MEK for clean-up.
- They are less flammable than solvent-based coatings because they do not contain organic solvents.
- Their low odor is a major advantage when painting interiors or poorly ventilated areas.
- They have a greater tolerance to residual substrate moisture during application.
- They have quick drying times, facilitating the application of a second coat. Furthermore, several water-based coatings could be applied in a single coat, such as Tnemec’s Series 1220 HydroLine, where the high-build version of it could be applied in high thicknesses reaching 305 microns (12 mils) per coat.
- They have excellent durability.
- They require less hazardous disposal.
- They are safer for users and the environment: No hazardous air pollutants (HAPs) or strong odors mean less risk of respiratory issues, headaches, and other health problems, making them more suitable for shop applications.
Although water-based coatings have several advantages compared to solvent-based coatings, they do have some limitations:
- They may require more coats to achieve the desired level of coverage compared to solvent-based coatings. This is because water-based coatings are typically lower in volume solids than solvent-based coatings.
- The finish produced by water-based coatings may not be as smooth or glossy as that produced by solvent-based coatings. This is because water can cause the pigments in the coating to settle out, resulting in a lower gloss finish.
- They can take longer to dry than solvent-based coatings, especially in high-humidity or low-temperature conditions. This can be a disadvantage for projects where a quick turnaround time is required. That said, water-based coatings have made huge strides in this area, and in many cases, they deserve another look when time is the deciding factor.
Overall, water-based coatings offer a number of advantages over solvent-based coatings. However, it is important to be aware of the disadvantages before choosing a coating system. The best coating system for a particular application will depend on a variety of factors, such as the desired performance characteristics, the budget, and the environmental regulations at play.
[Related Reading: Waterborne Coatings: When Regulations Meet Technology]

Tnemec Series 115 Uni-Bond DF is a high-performance, versatile coating appropriate for a variety of uses including exterior steel, humid environments, and dry interior environments. This waterborne, rust-inhibitive coating is used as a primer, intermediate, and finish coat on tanks, vessels, and other industrial and architectural metal substrates.
Advancements in Water-Based Coatings
Several enhancements in water-based coatings have occurred in recent years to overcome their disadvantages:
- New waterborne resins have been developed that offer improved performance characteristics, such as durability, flexibility, and chemical resistance. This has enabled the development of water-based coatings that can be used in a wider range of applications, such as high-performance architectural coatings, automotive coatings, industrial coatings, and marine coatings.
- New waterborne additives have been developed that can improve the performance of water-based coatings in a number of ways, such as improving drying time, enhancing adhesion, and increasing corrosion resistance. This has made these kinds of coatings more competitive with solvent-based coatings in terms of performance.
- New application technologies have been developed that make it easier to apply water-based coatings. For example, new high-volume low-pressure (HVLP) spray guns can be used to apply these coatings with minimal overspray. This has made water-based coatings more attractive to users, such as contractors and original equipment manufacturers.
Additionally, here are some specific examples of new water-based coatings that have been developed in the last 10–20 years:
- Water-based automotive coatings have been developed that offer the same level of performance as solvent-based automotive coatings but with a lower VOC content. These coatings are now being used by major automotive manufacturers around the world.
- Water-based industrial coatings have been developed that offer improved durability and corrosion resistance, making them suitable for a wider range of industrial applications. For example, water-based industrial coatings are now being used to protect bridges, pipelines, and other infrastructure from corrosion.
- Water-based marine coatings have been developed that offer excellent antifouling performance, protecting ships and boats from marine growth. These coatings are now being used by commercial and military fleets around the world.
- New or improved pigments have been developed that are more dispersible in water and offer better color performance. These new pigments are also often more environmentally friendly than traditional pigments.
- New or advanced additive technologies have been developed that can improve the performance of water-based coatings in a variety of ways. For example, new additives can improve the flow and leveling of coatings, reduce their VOC content, and increase their resistance to moisture, chemicals, and UV radiation. An example of this is Tnemec’s Series 975 Aerolon, a water-based insulation coating that uses advanced specialty particles to provide exceptional thermal conductivity and long-term performance.
The development of new water-based products is ongoing, and it is expected that these coatings will continue to become more competitive with solvent-based coatings in terms of performance, cost, and environmental impact.
Advancements in Application Methods for Water-Based Coatings
Modern formulations have also improved the application of water-based coatings in several ways. Here are some examples:
- Modern coatings can dry much faster than traditional water-based coatings. This is due to the use of new binder technologies and additives. Faster drying times can improve productivity and reduce the time it takes to complete a project. For example, Series 1205 Hydro-Zinc WBE from Tnemec is a water-based, zinc-rich primer that can become dry to touch in as little as two hours.
- These coatings have improved flow and leveling properties. This means that they spread out more evenly and smoothly, resulting in a better finish.
- Modern coatings have lower VOC content than traditional water-based coatings. This results in fewer harmful fumes, which is better for the environment and the health of the people applying the coating.
- New water-based coatings can be applied using brushes, rollers, or low-pressure spray equipment.
Conclusion
Water-based coatings are progressively growing in market share compared to solvent-based coatings. They were used first in limited applications as they had some drawbacks with respect to performance, drying times, and the durability of the coating as a whole when compared to solvent-based coatings. However, recent developments in binder and additive technology have drastically improved these setbacks, enabling water-based coatings to have better performance compared to their previous versions. To learn more about these coatings, contact a Tnemec representative.