How to choose a dispersant for a strongly alkaline system?The pH value is around 12, and it’s a water-based industrial paint.Discussing dispersants requires considering whether water or other solvents are used for dissolution. This will affect the choice of dispersant.If using a typical copolymer sodium carboxylate—CMC—it’s not very sensitive to solutions with a pH of 12. However, whether CMC can exhibit a dispersing effect depends on the grinding medium. If grinding inorganic pigments in pure water, traditional dispersants can be chosen.If dealing with difficult-to-disperse inorganic pigments or pigments with high oil absorption, and if you want to use alkali-resistant polymers with a pH of 12, polyurethane (PU) will be unstable. In water-based systems, a pH of 12 will kill phosphates, and titanates will also be unstable, making both unusable. However, acrylics can form a structure resistant to strong alkalis. Polyethers are also fine, because polyethers are synthesized in strong alkalis, such as ethylene oxide and propylene oxide. Polyethers are made from these two raw materials, so it’s perfectly acceptable to find polyether nonionic surfactants. A typical example is polyether amine, which has a typical structure that can withstand pH 12.
