With the development of the times, iron oxide pigments are widely used in our lives. The more important point for iron oxide pigments is the dispersibility. Huamei Chengde iron oxide pigment manufacturers will tell you:
When the iron oxide pigment disperses the pigment, many problems may occur, such as insignificant transparency or flocculation, poor product stability or rheology, which is closely related to the insufficient dispersion of the pigment.
In pure theory, "good dispersion" means that each pigment particle in the system is completely de-flocculated, that is, each pigment particle is wrapped by a thin layer of paint base or solvent. However, in practice this is difficult to achieve.
How does the dispersion of iron oxide pigments affect the performance of the coating?
Pigment dispersion can affect many important coating properties:
●Gloss
●Weather resistance and chemical resistance
●Storage period
●Color, tinting strength and transparency
●Hiding power
Gloss: If the iron oxide pigments are optimally dispersed, this can directly increase 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 gloss: if the pigments are not optimally dispersed, certain pigment agglomerates will have an adverse effect on the surface flatness, thus reducing the apparent gloss due to diffuse light scattering.
Resistance: Weather resistance and chemical resistance will also be mainly determined by the choice of paint base. Insufficient dispersion of the pigment particles here also reduces resistance. The pigment particles protruding from the surface provide attack points for chemicals and climate factors. Conversely, if the correctly selected pigment is optimally dispersed, the coating system resistance can only be improved, for example, by reflecting (TiO2) or absorbing ultraviolet radiation (iron oxide red) to improve weather resistance. Appropriate pigments or extender pigments can also improve the chemical resistance of the paint base if they are optimally dispersed.
Storage period: The storage period of the coating system largely depends on the quality of the pigment dispersion. When there is an excessive ratio of coarse pigment particles in the system, the adverse effect of the precipitation of the coarse pigment particles is easy to understand. Such stability problems are caused either by the so-called "post-wetting" of the pigment or by the re-flocculation of the opposite pigment. If the pigment is not completely re-flocculated at the beginning of the dispersion to the complete dispersion, post-wetting can be imparted. The reason for the re-flocculation of the previously correctly dispersed pigment dispersion is that the stability of the pigment paste is good enough. This largely depends on the stability of the paint base or the ratio of paint base to solvent during the dispersion process. Solvents generally have excellent wetting properties, and the paint base is beneficial to stability. The problem is the ideal combination of wetting (= solvent) and stability (= paint base).
