The Waterborne Symposium

Abstract
Coatings are complex composites designed to have a stable shelf-life, apply easily to a substrate, and provide lasting durability in varied environments. These performance criteria require disparate materials to be finely dispersed and work cohesively, which presents a major challenge as composites can be unstable and ultimately fail at points of inconsistency. To address this, the first thing a new paint chemist learns is that wetting agents are mandatory in allowing mineral fillers to disperse properly. Without them, these inorganic particles generally reject their organic media, agglomerate and settle out. It would be imprudent to forgo wetting agents.
Another well-known, tried-and-true technique to stabilize composites and improve their uniformity is to use high-quality, gel-grade attapulgite mineral products. They have been common in paint applications for several decades as thixotropic thickeners for low-shear flow and leveling, sag and spatter resistance and other rheology benefits. However, a seemingly forgotten higher value is their function as excellent stabilizers due to their unique colloidal lathe-shaped particles forming a stable lattice structure. This keeps liquids and particles more evenly dispersed and suspended, generating important benefits well beyond rheological properties; such as syneresis control, improved tint strength, hiding and freeze-thaw, and reduced color float and flooding.
This article gives a brief history of attapulgite, a description of its mechanism that sets it apart from other thixotropic thickeners and stabilizers, and discusses its performance benefits in coatings.