A dispersant is a surfactant that possesses both lipophilic and hydrophilic properties within its molecule. It can uniformly disperse solid and liquid particles of inorganic and organic pigments that are difficult to dissolve in liquids, while also preventing particle sedimentation and aggregation, thus forming a stable suspension.
The role of dispersants: The role of dispersants is to reduce the time and energy required to complete the dispersion process, stabilize the dispersed pigment dispersion, modify the surface properties of pigment particles, and adjust the mobility of pigment particles.
Specifically, this manifests in the following aspects:
- Enhancing gloss and improving leveling effect. Gloss primarily depends on the scattering of light by the coating surface (i.e., a certain degree of smoothness is sufficient. Of course, testing instruments are needed to determine if it is smooth enough, considering not only the number and shape of the primary particles but also their bonding method). When the particle size is less than 1/2 of the incident light (this value is uncertain), it manifests as refracted light, and the gloss will not increase further. Similarly, the hiding power, which relies mainly on scattering to provide hiding power, will not increase (except for carbon black, which mainly relies on light absorption; organic pigments are forgotten). Note: This incident light refers to the visible light range. Leveling is difficult to define precisely; however, note that reducing the number of primary particles reduces its structural viscosity, but the increase in specific surface area reduces the amount of free resin. Whether there is a balance point is uncertain, but generally, finer leveling in powder coatings is not necessarily better.
- Preventing color floating and mottling.
- Improving tinting strength. Note that in automatic color matching systems, higher tinting strength is not always better.
- Reducing viscosity and increasing pigment loading.
- Reducing flocculation is important, but finer particles have higher surface energy, requiring dispersants with higher adsorption strength. However, dispersants with excessively high adsorption strength may negatively impact coating performance.
- Increasing storage stability is similar to the above; insufficient dispersant stability can actually worsen storage stability (although your image appears fine).
- Increasing color development, color saturation, transparency (organic pigments), or hiding power (inorganic pigments).
TEGO Dispersants help wet and stabilize pigments, preventing floating, blooming, and sedimentation. They maintain stable hiding power and color intensity during storage, ensuring maximum color yield and minimal grinding steps. Because these additives reduce viscosity, they allow for maximum pigment concentration during dispersion, resulting in more cost-effective coatings and pigment concentrates. TEGO Dispers 757 W is recommended for producing water-based pigment concentrates. It is also the preferred product for corrosion-resistant water-based coatings. Like TEGODispers 750W and TEGODispers 755W, these products meet the highest requirements for optical and rheological properties. For general-purpose pigments suitable for both solvent-based and water-based formulations, the TEGODispers 65x series is the current market standard for ethoxyalkylphenol-free products. TEGODispers 656, 670, and 685 are particularly suitable for modern solvent-based formulations. In UV systems, TEGODispers 685 is suitable for all pigments, and TEGODispers 688 is suitable for matting agents. All TEGODispers products are ethoxyalkylphenol-free.
