How anti-sinking agents work?

Anti-sinking agents help prevent pigments or fillers in coatings from settling to the bottom during storage or application, ensuring a uniform distribution throughout the medium. They work by controlling the viscosity and rheology of the formulation, stabilizing the suspended particles, and often creating a network structure to maintain even dispersion. Here's how they work in detail:

Thixotropic Effect: Many anti-sinking agents provide a thixotropic (shear-thinning) effect. When stirred, the viscosity decreases, allowing easy application. Once at rest, the viscosity increases, preventing particles from sinking.

Network Formation: Certain agents, like fumed silica or organoclays, form a 3D network structure in the medium. This structure traps pigment particles, which prevents them from settling.

Electrostatic and Steric Stabilization: Some anti-sinking agents stabilize particles through electrostatic repulsion or steric hindrance, ensuring they stay evenly suspended.

Increased Yield Stress: Anti-sinking agents often increase the yield stress of the system, meaning a higher force is needed for particles to start moving or settling. This property is particularly useful for heavy particles like metallic pigments.

Compatibility with Formulation: To work effectively, anti-sinking agents need to be compatible with the specific solvent, resin, or system they’re used in, as the effectiveness can vary based on formulation chemistry.