Effect of Dispersing Agents on the Stability of Recycled Paints

In a circular economy approach, paint waste is recycled and reformulated to be transformed into new paints. In this regard, the lifespan of recycled paints must be properly assessed and extended beyond their preliminary specifications. This study aimed to improve the stability of waterborne acrylic paints by adding dispersing agents. Seventeen dispersing agents were added to two formulations of recycled paints: one stable, and one showing signs of instability. Their stability was characterized by analytical centrifugation and quantification of the supernatant. Among the tested dispersing agents, four showed a significant improvement in stability in both tests. These dispersants belong to the four possible categories of stabilization mechanisms: electrostatic, steric, electrosteric, and controlled stabilization. Electrosteric dispersing agents are especially effective in both paints. The combination of two dispersants does not have a synergistic effect.