Dispersion is to form a resin or polymer coating layer on the surface of pigment carbon black, so that the original pigment agglomerates form more stable small agglomerates. The affinity or force of sufficient strength can form a stronger and more stable adsorption layer on the surface of the pigment, that is, the coating layer; at the same time, the solvent and resin in the carbon black dispersion system will also compete for the adsorption of the pigment, and the dispersant must also form with the pigment. Stronger adsorption than resins and solvents is required for dispersion.
The pigment carbon black in the carbon black series is a better pigment for black coatings and paints. However, sometimes due to many reasons, flocculation will occur over time. If this phenomenon is to be well resolved, the flocculation mechanism of carbon black must first be clarified. The dispersion of carbon black in various pigments is the most difficult, due to the strong aggregation between carbon black particles and the high oil absorption. In addition, carbon black, especially the post-oxidized pigment carbon black, generally has a relatively large surface area and is easy to absorb moisture in the surrounding environment.
In addition, in order to form a stable dispersion system, there must be a long enough solvated chain segment, that is, the dispersant must have a suitable molecular weight, so that during the storage process of the coating, the carbon black particles will not be due to the collision caused by Brownian motion. Re-flocculate into larger particles or prolong the time of flocculation. Under the same formulation conditions, if the amount of pigment carbon black is large, and the amount of carbon black dispersant is insufficient, it cannot achieve the best dispersion state. Only when the amount of carbon black used and the amount of dispersant are adjusted, can the dispersion be very Well, the gloss is very glossy.
We believe that to compare the blackness and hue of different carbon blacks, the carbon black must be completely dispersed. If a resin with poor wettability is used, and an unsuitable carbon black dispersant is used, the performance of carbon black cannot be truly exhibited. Especially for high-pigment carbon black, if a suitable dispersant is not used, or a good dispersant is used but the amount added is insufficient, or the dispersant is somewhat incompatible with the resin system, the dispersed pigment particles are easy to flocculate. Thus affecting the evaluation of its blackness.