Pigments are a key part of inks and coatings, providing color and opacity while adding to the performance and durability of the end-use product. Because they are insoluble particulate materials, they need additives to disperse them in a liquid medium—like a binder or solvent—to deliver the preferred color and properties.

Dispersants or dispersing agents are the additives used to wet, disperse and stabilize dry pigment powders in a variety of liquid formulations. The way pigments are dispersed in the ink or coating medium is important for achieving consistent color and avoiding issues like flocculation/agglomeration.

While the function of dispersants is similar in inks and coatings, they differ greatly in design and selection because of differences in the pigment type and requirements based on application uses, goals and performance needs.

Pigments in Inks

With inks in printing and packaging applications, the emphasis is on delivering a fine, uniform dispersion to achieve vibrant colors through high pigment loading while also preventing clogging in printheads. Inks typically use highly colored, more transparent organic pigments designed for color overlay and mixing. This transparency is essential in applications like digital printing, where layered colors (e.g., cyan, magenta, yellow, black, and spot colors) create the final image. Different colors are produced by overlaying a narrower range of colors than in coatings.

To achieve strong color intensity despite applying very thin films, inks often contain a higher concentration of finely dispersed pigments. This ensures sufficient optical density, which enhances color richness without requiring a thick layer. Because ink layers are so thin, large pigment particles are problematic, as they can lead to poor dispersion and increased opacity, undermining the ink's purpose. Larger particles may also not fit well in the thin film and could negatively impact print quality.

Pigments in Coatings

With coatings, color is still important, but so are stability and protective performance. Unlike inks, coatings often use more opaque pigments chosen for properties like durability and UV resistance, especially for exterior or protective uses. That’s because the final appearance depends more on the top layer's color. Coatings rely more on directly using pigments in the desired color rather than overlaying or mixing colors, as is common in ink systems. For example, if orange is the desired color for a can of paint, an orange pigment would be chosen rather than using a red pigment with a yellow on top of it, like in an ink.

Coatings are often applied in thicker films, so larger pigment particles are acceptable, and even beneficial. Larger particles in coatings can contribute to greater UV resistance, making them more suitable for exterior or protective applications. Durability and long-term color retention are more important than optical density, so smaller particles—which might degrade faster—are sometimes avoided to maintain color integrity over time.

Choosing the Right Dispersant

Dispersants are highly specialized additives used to wet, disperse and stabilize dry pigment powders in a variety of liquid formulations, including inks and coatings. The process of dispersion is undertaken to get as close as possible to the original primary particle size. Achieving that improves the application process and provides better end-use performance. Without an additive (a dispersant), the smaller particles would naturally recombine (agglomeration). An efficient dispersing agent can also serve as a wetting agent and a stabilizing agent.

Pigment dispersants are two-component polymeric structures, with the anchoring group providing strong adsorption onto the pigment surface. Polymeric chains, which are attached to the anchor group, provide the stabilization.

Dispersing pigments in inks and coatings involves similar foundational goals—achieving uniform pigment distribution and stability—but there are important differences based on the distinct requirements and formulations of each system.

	Inks	Coatings
Dispersion Needs	Require ultra-fine pigment dispersion (nanoscale particles), avoiding flow issues or color shifts during printing.	Optimized for stability under stress. Focus on long-term storage stability (anti-settling), dispersion efficiency in high-load systems (e.g., fillers), and final coating properties like gloss and coverage.
Performance Needs	High optical clarity, fine particle size, low viscosity.	Opacity, weather/chemical resistance, film integrity.
Stability Needs	Very high—must not settle or flocculate during storage or use.	High, but sometimes minor settling is acceptable if easily re-dispersed.
Compatibility	Simpler systems with fewer additives. While additives like waxes for scratch resistance may still be present, the overall formulation tends to be more straightforward, and the compatibility demands are lower.	Broad compatibility is needed because coatings typically involve more complex formulations. They may include various additives for areas like UV protection, corrosion resistance, flash rust protection, scratch resistance (e.g., waxes) and adhesion promotion.

A Broad Product Range

Lubrizol supports both the ink and coating industries by offering tailored dispersant technologies designed to meet the specific performance and formulation requirements of each application.

Lubrizol’s advantage lies in a broad portfolio of dispersant products tailored for:

Inks (including digital printing)
Paints and coatings
Specialized applications, like advanced ceramics and Li-ion batteries.

This broad product range enables Lubrizol to work with customers to select the most suitable dispersant for each application to meet varying performance and formulation efficiency needs. For industrial coatings that don’t have high-performance demands, simpler dispersants might work. For more complex coatings, like in automotive applications, high-performance dispersants will typically be needed due to their extreme durability requirements, such as UV resistance, barrier properties and long-term outdoor exposure testing (e.g., 2+ years). The dispersant can’t compromise the protective properties of the coating.

A major challenge in coatings is the need for multi-compatibility—a single colorant system might be required to function across a variety of different coating formulations. In contrast, ink systems are typically tightly optimized for specific combinations of components and precision dispersion and printability, reducing the need for such broad adaptability. Selection of the dispersant needs to align with specific formulations, processes and regulatory standards, reflecting the unique demands of each application.

Lubrizol Dispersant Technology for Inks

In inks where only a limited number of pigments are used, Lubrizol Solsperse™ 87000 is an example of an optimized dispersant specifically developed to enhance the dispersion and stability of red pigments. It is particularly effective for pigment red 57.1 in UV systems to prevent gelation.

Solsperse 87000 is an example of Lubrizol’s targeted approach to respond to customer needs, where ink formulators often choose the “best-in-class” dispersant for each pigment, rather than a universal option.

Lubrizol has also invested in developing dispersants for UV-curable inks, where pigments like magentas, some yellows and silica matting agents can be challenging to disperse and stabilize. These systems are often solvent-free, increasing the formulation complexity since there are fewer tools available for pigment stabilization. In response, Lubrizol has focused on creating dispersants that are 100%-active liquid formulations, making them easier to handle and incorporate into solvent-free systems and that are highly effective in stabilizing pigments that typically pose dispersion challenges in UV ink environments.

Lubrizol Dispersant Technology for Coatings

As the coatings and paint industry increasingly moves toward water-based materials, Lubrizol has responded by developing dispersants that help overcome the unique formulation challenges of water-based systems, including broad compatibility with diverse raw materials and the need for high performance.

Solsperse™ Hyperdispersant technology and the dispersants developed using this technology are examples of the range of dispersants to meet different coating needs while enabling the production of highly loaded, highly stable, broadly compatible dispersions.

A few of these dispersants include:

Solsperse W100 – a general-purpose dispersant in water-based systems that offers broad compatibility across a wide range of pigments and formulations.
Solsperse W210 – a 100%-active, more specialized dispersant optimized for high-end organic pigments and carbon black. It is suitable for applications requiring high color strength and stability, where pigment dispersion is more technically demanding.
Solsperse W430 – designed specifically for water-based wood coatings that require both effective pigment dispersion and high stain resistance, such as household stains like coffee and red wine. Solsperse W430 maintains barrier properties while delivering excellent dispersion performance.

Lubrizol offers specialized dispersant solutions that cater to the distinct formulation and performance requirements of inks and coatings, offering a breadth of technologies to meet unique challenges across a wide range of end uses.

The Differences in Dispersing Pigments in Inks and Coatings