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There are many types of dispersants used in industrial coatings. Substances that can wet and stabilize pigments can be used as dispersants, with at least 1000 or more. It has a dispersing effect. According to its structure, we can roughly divide it into the following three categories.

The first category is wetting and dispersing agents with low to medium molecular weight, which includes the following subcategories. The first is anionic wetting and dispersing agents, whose anchoring groups carry negative charges and are acidic, suitable for alkaline pigments and fillers. Various pigments and fillers such as titanium dioxide, barium sulfate, calcium carbonate, etc. contain some alkaline carbon black.

The second is cationic dispersants, whose anchoring groups are positively charged and mainly include various amine salts, quaternary ammonium salts, acylammonium phosphates, etc. They have good dispersion effects on carbon black and iron oxide organic pigments.

The third is non-ionic wetting and dispersing agents, which cannot ionize and do not carry charges. They usually have weak adsorption on the surface of pigments and are mainly used in water-based coatings to reduce their surface tension and improve their wetting properties, such as fatty acid epoxyethane adducts, polyethylene glycol polyols, and derivatives of polyethyleneimine.

The fourth is an amphoteric wetting and dispersing agent, which is an anchoring group that contains both anions and cations. A typical product is a phosphate ester polymer.

The fifth one is an electrically neutral wetting and dispersing agent. The size of anionic and cationic groups in the molecular structure is basically equal, and the entire molecule is neutral, but it also has polarity. For example, oil amino oleic acid esters, which are the first major category, are low molecular weight wetting and dispersing agents. Their molecular weight is usually between a few hundred and two thousand, with some slightly higher.

The second major category is polymer based hyperdispersants, with typical molecular weights ranging from 5000 to 20000, and some even reaching 30000 to 50000. This type of dispersant is also the most commonly used and stable dispersant. Polymer dispersants are also divided into several categories, the first of which is polyester type, mainly including polycaprolactone polyols and polyethyleneimine block copolymers.

The second one is acrylic polymer dispersant, which mainly uses acrylic monomers or styrene as the main chain, and then introduces this anchoring group. The third is a high molecular weight dispersant based on polyurethane, which contains polyurethane structures in its molecular chains and utilizes the structure of polyurethane to introduce steric hindrance groups or anchoring groups. It is the most commonly used polymer dispersant in solvent based coating systems, followed by styrene maleic anhydride and polyetheramine. This type is mainly used for water-based coatings.

The third major category is controlled radical type hyperdispersants, which use the latest CNC radical polymerization technology to make the structure of dispersants more regular. The most commonly used methods are ATRP (atom transfer radical polymerization) and RAFT, which is called reversible layer breaking chain transfer controlled radical polymerization. That includes methods such as TEMPO, which can make the molecular weight distribution of dispersants more concentrated through controlled radical polymerization technology. The anchoring groups are also more concentrated, resulting in higher efficiency. The dispersion effect of controlled free agents is generally better than that of conventional polymer dispersants.