Three Key Factors in Selecting Dispersants: How to Achieve Precise Matching with Coating Systems

In coating formulation design, the choice of dispersant directly influences pigment dispersion, storage stability and the final film quality. To select a highly effective dispersant suited to the system, a comprehensive assessment must be made based on three core criteria: stabilisation mechanisms, pigment compatibility and system compatibility. Only through a scientific selection process can dispersion performance be maximised.

Firstly, the appropriate stabilisation method must be selected. Before choosing a dispersant, it is necessary to determine whether the system is suited to electrostatic stabilisation or steric stabilisation, as this is closely related to the coating medium. Solvent-based systems have low polarity and cannot achieve electrostatic stabilisation; particle dispersion can only be achieved through steric effects. In water-based systems and certain polar solvent systems, electrostatic stabilisation is the common method and is also the mainstream stabilisation mechanism for conventional coatings such as emulsion paints. In complex formulation systems, steric stabilisation offers superior stability. Today, many new high-efficiency dispersants possess dual stabilisation properties, achieving both electrostatic and steric stabilisation within a single molecular structure, thereby meeting the demands of a wider range of high-end coating systems.

Secondly, the anchoring sites for pigments and fillers must be matched. For a dispersant to function effectively, its molecules must be able to adsorb firmly onto the surface of solid particles. Prior to selection, it is essential to clarify whether the dispersants are intended for organic or inorganic pigments, or for surface-treated or untreated powders, in order to select a dispersant with the appropriate adsorption groups. Hydrogen bonding is the most common anchoring mechanism; the acid-base interactions and donor-acceptor interactions frequently mentioned in the industry are, in essence, designed to ensure that the dispersant anchors more securely to the particle surface, thereby preventing flocculation caused by desorption.

Finally, good system compatibility must be ensured. The non-adsorbing components of the dispersant must be fully compatible with the binder system; this is key to ensuring liquid-phase stability and enhancing the film-forming properties of the coating. Poor compatibility can lead to pigment flocculation and coarsening during the wet stage, and may result in issues such as uneven gloss and mottling after application and film formation. Only when these three factors work in concert can a stable, highly efficient and highly compatible dispersant be selected to safeguard the quality of the coating.

Dispersing agent 2513

Dispersing agent 5040

Aerogel dispersant