Encapsulation of an organic phthalocyanine blue pigment into polystyrene latex particles using a miniemulsion polymerization process

Abstract

Abstract Aqueous dispersions of polystyrene latexes encapsulating a copper phthalocyanine blue pigment were formulated using the miniemulsion polymerization technique. The organic pigment was first suspended into the monomer phase, and the resulting oily suspension was subsequently converted into stable miniemulsion droplets using various types and concentrations of hydrophobe (costabilizer). The pigmented monomer emulsions were finally polymerized using potassium persulfate as the initiator. It was shown that the organic pigment could stabilize the miniemulsion droplets, and be thus satisfactorily encapsulated without introducing any other compound in the formulation. In a subsequent approach, the stability of the miniemulsion droplets was improved by using either hexadecane, hexadecanol or a polystyrene prepolymer as the hydrophobe. Dynamic light scattering and transmission electron microscopy measurements showed that the size and the morphology of the resulting pigmented polymer particles were greatly influenced by the presence of the costabilizer. © 2003 Society of Chemical Industry