Project Report on Sodium Polyacrylae Dispersant For Use in Water Based Paints (Eiri-1591)

The choice of the dispersing agents is a key issue in the coating water based paints. Formulators have to find the most suitable products for their formulation taking into account the final application of their coating, the coating system (water based, solvent based etc.) and the other additives. The role of the dispersing agents is to enhance the dispersion process and ensure a fine particle size in order to stabilize pigments in the resin solution. As explained earlier, an efficient dispersant has to perform the three main functions: pigment wetting, dispersing, and stabilizing. Dispersing agents generally differ for aqueous and solvent-based coatings.The main differences of those two types of dispersants being the molecular weight, the stabilization mechanism and the resulting let down stability. Surfactants are conventional low molecular weight dispersing agents. Surfactant molecules are able to modify the properties and, in particular, they lower the interfacial tension between the pigment and the resin solution. This surface activity arises because the surfactants' structure consists of two groups of contrasting solubility or polarity. In aqueous systems, the polar group is known as a hydrophilic group and the non-polar group as hydrophobic or lipophilic. In non-aqueous systems, the polar group is known as the oleophobic group and the non-polar group as oleophilic. Surfactants are classified according to their chemical structure and more specifically, their polar group: anionic, cationic, electroneutral and non-ionic.