Clay-assisted stabilization of organic pigments for paint application

This study investigates the feasibility of utilizing commercial clays such as smectite (Sm), mica (Mi), kaolinite (Kao), and laponite (Lap), as alternative, non-surfactant based dispersing agents in the preparation of aqueous dispersions of phthalocyanine green (PG) and quinophthalone yellow (QY). The stability of the dispersion was determined using UVVis spectroscopic measurements after subjecting the dispersions to simulated aging through accelerated sedimentation. Preliminary tests at a low concentration (~0.1% w/w) demonstrated the dispersing capabilities of the clay with smectite and laponite-based pigment dispersion exhibiting the highest stabilities. Differences in the dispersing capabilities of the clays used were attributed to their structural diversity. Among the clays used, Sm resulted in acceptable pigment dispersion using 0.5% to 5% Sm w/w. Sm-assisted pigment dispersions prepared with ~15% pigment loading showed stable and good pigment dispersions, enough to be compared to an industry standard prepared based on conventional surfactant-formulated pigment dispersion