Dispersants are used to disperse various powders in solvents in a reasonable manner, and to stably suspend various solids in solvents (or dispersions) through certain charge repulsion principles or polymer steric hindrance effects. Dispersants are surfactants that have two opposite properties, lipophilicity and hydrophilicity, in their molecules. They can evenly disperse the solid and liquid particles of inorganic and organic pigments that are difficult to dissolve in liquids.
Non-corrosive, non-flammable, efficient and environmentally friendly water-based dispersants are infinitely soluble in water and insoluble in organic solvents such as ethanol, acetone, and benzene. They form floccules when in contact with concentrated alkali. They have excellent dispersing effects on various pigments such as kaolin, titanium dioxide, calcium carbonate, barium sulfate, talcum powder, zinc oxide, and iron oxide yellow, and are also suitable for the dispersion of mixed pigments.
The advantages and disadvantages of water-based dispersants are as follows:

  1. Water-based coatings have high requirements for the cleanliness of the construction process and the surface of the material. Because the surface tension of water is large, dirt can easily cause shrinkage holes in the coating film.
  2. Water-based paint has poor dispersion stability against strong mechanical forces. When the flow rate in the conveying pipeline changes sharply, the dispersed particles are compressed into solid particles, causing pitting of the coating film. The conveying pipeline is required to be in good shape and the pipe wall is free of defects.
  3. Water-based paint is highly corrosive to coating equipment, and anti-corrosion lining or stainless steel materials are required, and the equipment cost is high. Water-based paint corrodes the conveying pipeline, dissolves metals, causes the dispersed particles to precipitate, and pitting of the coating film occurs, and stainless steel pipes are also required.
  4. Baking water-based paint has strict requirements on construction environment conditions (temperature and humidity), which increases the investment in temperature and humidity control equipment, and also increases energy consumption.
  5. The latent heat of evaporation of water in water-based paint is large, and the energy consumption of baking is large. Cathodic electrophoretic paint needs to be baked at 180°C; while latex paint takes a long time to completely dry.