What Is The Effect Of Pigment Dispersion On The Coating?
In the use of coatings, people often encounter flocculation, color or transparency, fluid change or poor stability, these problems are not sufficiently dispersed with pigments have a close relationship.
Purely theoretically, "dispersed well" means that each pigment particle in the system is completely de-flocculation, i.e. each pigment particle is encased in a thin layer of paint or solvent. In practice, however, this is hard to achieve. So, what is the effect of pigment dispersion on the performance of the coating?
1, gloss: If the pigment gets the best dispersion, then it can directly improve the gloss. In principle, gloss is determined by the performance of the paint base. Adding the necessary pigments can only have an adverse effect on the gloss: if the pigments are not optimally dispersed, some pigment clusters will adversely affect the surface flatness, thus reducing the performance gloss due to diffuse scattering of light.
2, resistance: weather resistance and chemical resistance will be mainly determined by the choice of paint base. Inadequate dispersion of pigment particles here also reduces resistance. The pigment particles protruding from the surface provide the attack point for chemicals and climatic factors. Conversely, if the correctly selected pigments are optimally dispersed, they can only be improved by improving the resistance of the coating system, for example, by reflecting (TiO2) or absorbing ultraviolet radiation (iron oxide red). Proper pigments or physical pigments can also improve the chemical resistance of the paint base if they are optimally dispersed.
3, storage period: the storage period of the paint system depends to a large extent on the quality of pigment dispersion. When there are excessive proportions of coarse pigment particles in the system, the adverse effects of thick particle precipitation of pigments are easy to understand. Such stability problems are either caused by the so-called pigment "rear wetting" or by the opposite pigment re-flocculation. If the pigment is not fully re-condensed when it is beginning to disperse to complete dispersion, it can be given to the rear wetting. The reason for the re-flocculation of the previously correctly dispersed pigment dispersion is that the pigment slurry is stable enough. Much depends on the stability of the dispersal paint base or the ratio of the paint base, solvent, during dispersion. Solvents generally have excellent wetting properties, and paint base is beneficial to stability. The problem is that wetting (solvent) and stability (-paint-based) are to achieve the desired combination.
4. Color, color strength, transparency and cover: all of these properties depend largely on the pigment surface used, the "best dispersion". The complete dispersion of the pigment in the case of the cover pigment can lead to an increased masking force, resulting in greater color intensity of the toning slurry (no flocculation), while in the case of transparent pigments, it can make transparency better. For all pigments, the complete dispersion of the pigment can result in a complete display of the hue and "color purity" of the color.
