Dispersants can also improve pigment wetting

Pigment dispersant HH2011X mainly relies on electrostatic repulsion to stabilize pigment particles in water-based systems. Polymers containing acrylic acid or maleic anhydride are often used to disperse inorganic pigment particles. Carbon black and organic pigments are mainly stabilized by nonylphenol polyoxyethylene ether, but because nonylphenol is toxic, it has been banned in paint formulations. Hydrophobic-hydrophilic amphiphilic block polymer is an excellent pigment dispersant. The hydrophobic segment in the dispersant molecule is coated on the particle surface through the hydrophobic interaction with carbon black and organic pigments, and the hydrophilic segment is coated on the particle surface through both electrostatic and steric hindrance. Provides stability. By controlling the composition and degree of polymerization of the hydrophobic and hydrophilic segments, the maximum dispersion effect can be obtained.

There are significant differences in pigment dispersion in solvent and water-based systems. In solvent systems, wetting is usually easier because the surface tension of the solvent and resin is low and no special additives are needed to improve pigment wetting. Due to the high surface tension of water, special additives are needed to reduce the surface tension so that low surface tension pigments can be fully wetted by the water phase.

Reversible addition-fragmentation chain transfer radical polymerization (RAFT) can synthesize block polymers. Hydrophobic-hydrophilic amphiphilic block polymer aqueous dispersant HD-2011 was synthesized using RAFT technology, which is used to disperse carbon black and organic pigments in water. After testing, Hohuan Chemical HH2011 dispersant has a good dispersing effect on carbon black and organic pigments. The FW200 color paste and PV23 color paste prepared with HH2011 have narrow pigment particle size distribution, good fluidity, and good thermal stability. The color paste is in latex Good color acceptance in paint.

In coatings, pigments are an important component. Pigments with optimized particle sizes have the greatest hiding power and tinting strength. However, during transportation and storage, primary pigment particles will form aggregates or agglomerates. During the coating production process, there is a need to redisperse aggregates or agglomerates into primary particles and to stabilize the primary particles. Only in this way can pigments provide high tinting strength, pigment weather resistance, and storage stability. During the dispersion process, the liquid phase first wets the pigment particles, and then mechanical force breaks up the aggregates. The function of the dispersant is to stabilize the broken particles and prevent them from re-aggregating.