BDMA is also used in the synthesis of quaternary ammonium salts, production of cationic surface active powerful bactericides, etc.
There is a clear difference between the preparation of solvent-based and wax for water-based coatings. The wetting step of solvent-based coatings is relatively simple. Because the solvents and resins used have low surface tension1, no special additives are needed to improve the wetting. The surface tension (mN/m) of some solvents and resins are as follows:
Xylene 30 amino resin 58
Butyl acetate 25 oil-free polyester 47
White alcohol 24 Methyl methacrylate 41
Long oil soy oil alkyd 37
Due to the high surface tension of water, water-based systems require special additives to reduce the surface tension and satisfy the wetting of the pigment. Aqueous dispersant: 35~45mN/m; water: 72.7mN/m.
In addition, in aqueous systems, various mechanisms can be used to stabilize the dispersion of pigments. In solvent-based systems, steric hindrance can be used to prevent re-agglomeration. Traditional latex paint uses electrostatic repulsion, and the principle of pigment dispersion and stability is shown in Figure 26-6. In architectural coatings, most water-based paints use anionic dispersants, such as polyacrylate , which is widely used. However, it is found that it cannot provide sufficient stability to organic pigments in color pastes, and is compatible with most coatings. Very bad.
Charge stability (b) steric hindrance or entropy stability
The principle of pigment dispersion stability
Dispersant for solvent-based colorants
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