One of the most important steps in the production of pigmented coatings is the homogeneous distribution of solid pigments within the liquid binder solution. If this pigment grinding step is not optimized, then a wide variety of defects can occur. Wetting additives accelerate the wetting of pigment agglomerates by the resin; dispersing additives improve the stabilization of the pigment dispersion. One and the same product can oftentimes function as both the wetting and the dispersing additive. Dispersing additives absorb onto the pigment surface and therefore maintain proper pigment spacing through electrostatic repulsion and/or steric hindrance, thus reducing the tendency towards uncontrolled flocculation.
Controlled flocculating additives (BYK®-P 104, BYK®-P 104S, BYK®-220 S) function as a bridge between pigment particles, forming a three-dimension network structure, which lead to thixotropic behavior. Through the above rheological behavior, properties such as sagging and settling can be positively influenced.
Deflocculating additives (such as BYK®-151 or BYK®-154 in aqueous and BYK®-9075 or BYK®-9077 in solvent-borne systems) adsorb onto the pigment surface and consequently transfer their charge to the pigment particle. The strong electric charges drastically reduce flocculation and thus stabilize the deflocculated state.