Fatty Alcohol Ethoxylate AEO-9 (HLB≈13, Nonionic)

HLB (Hydrophilic-Lipophilic Balance) predicts the primary function of nonionic surfactants: HLB 3–6 is best for water-in-oil emulsification; HLB 7–9 is for pigment wetting and oil emulsification; HLB 10–16 is for oil-in-water emulsification and substrate wetting; HLB >16 is for solubilization. For pigment grinding in waterborne coatings, HLB 10–13 nonionic surfactants provide good balance of pigment surface wetting and aqueous dispersion stability. Blending two surfactants of different HLB to hit the target HLB often gives better performance than a single surfactant at the same HLB.