Different methods of drying α-and β-Copper Phthalocyanine were tried

and the relation between the capillary aggregation of the pigment and particle size distribution was investigated. In drying α-Copper Phthalocyanine

organic solvent flushing and salt co-precipitation were found not to induce any phase transformation when a proper solvent was used. A series of surfactants

including anionic

cationic

amphoteric as well as a rosin soap

were tried for the surface treatment of α-Copper Phthalo-cyanine in order to control particle size

color shade and strength

and dis-persibility of the pigment. Critical surface tension of the solid was determined experimentally in order to verify the influence of surface

treatment on the properties of α-Copper Phthalocyanine. Two modes of adsorption of a surfactant on the pigment surface were proposed

that is

the hydrophilic single-point standing adsorption and the hydrophobic multi-point lying adsorption. The variation of the dispersion stability of the pigment after treatment with different surfactants was discussed in the light of the proposed modes of adsonption.