Raw material cost increases, regulatory compliance and end-user market demand for more environmentally friendly products are some of the challenges faced by paint formulators. The Archer Daniels Midland Company (ADM) is addressing these needs by introducing cost-effective pigment dispersants derived primarily from renewable resources. This article provides an overview of the new dispersant technology, its chemistry and mode of action, presentation of results obtained from testing in model formulations, and a discussion on advantages over current industry practice. The test results support claims that these dispersants can be used to formulate paints with lower cost and excellent stability, together with improved color acceptance, contrast ratios, scrub resistance and enhanced hard water tolerance with less susceptibility to formulation failure from raw material quality variation.
The new renewable dispersant technology is based on amphoteric, non-polymeric chemistry with a schematic molecular structure as shown in Figure 1. The amphoteric structure provides significant advantages over the anionic, nonionic or cationic dispersants traditionally used in paints. Along with the strong pigment anchoring amphoteric head group there are also enhanced fatty acid tails that carry an additional pigment anchoring group. The amphoteric head provides an important key to improved wetting, anchoring and stabilization of pigments. Additional electrostatic and steric stability and compatibility contributions come from the rest of the structure. The unique molecular structure excels at stabilization over a wide variety of pigment chemistries, but is particularly effective with inorganic pigments such as titanium dioxide. The new dispersant has the added benefit of improved surface tension reduction to accelerate pigment wetting and de-aeration, reducing grind energy input and dispersion time without the use of an additional surfactant.