Why Is Used Dispersants in the Manufacturing of Paint?
The effective dispersion of pigments and fillers in a coating system is critical and affects many aspects associated with the final performance of the system.
Among these aspects we can mention the energy required to obtain the milling and good color development, final product stability and water resistance and alkali dry film.
Dispersants greatly influence all these factors and require careful selection to optimize the systems.
The aqueous coatings historically followed the guidelines of the “coatings” of the paper industry: at first it was established that the polyphosphates were dispersing and cost-effective for titanium dioxide, calcium carbonate and kaolin.
When the industry became more efficient it should improve, too, the synthetic polyelectrolyte dispersants varying composition, are now well known and used in the coatings industry. These products are able to adsorb strongly on the pigment particles to a greater or lesser extent depending on the pigment system in which they are used.
The final assessment of any additive in a coating system is how the additive affects the other properties of sistema.Ahora well, assuming a wide range of chemicals can act as dispersing pigments themselves, and understanding the chemistry base contributes to the desirable properties of the coatings, we ask:
What are the potential advantages of using polymeric dispersants?
In physicochemical terms, polymeric dispersants can reduce interactions between pigment particles in a much more efficient than conventional dispersants. The most obvious is to reduce the viscosity of the formulation.
The ability to reduce interactions between pigment particles also confers certain benefits associated with the optimization of tinting pigments. We can subdivide the advantages of these dispersants in productivity gains (higher concentrations of pigment), color power (more efficient use of color) and coating quality.
1. Increased productivity:
It is possible to disperse pigment in a polymeric dispersant solution better than a resin solution. This will provide a base grind much higher concentration of pigment to any selected viscosity.
The concentrate is then diluted with grinding the resin to give the traditional coating.
There is an increase in productivity by achieving higher concentrations of pigment in the grind and with this, more effective utilization of equipment.
This is used in those considered difficult to disperse pigments and resins considered low dispersing power.
2. Increased strength of color:
All providers of dispersants say their use increases the effectiveness of the strength of the pigment, especially in these cases. This proved to be true if the size of the pigment particle is less than 0.1 microns.
It is recognized that the intrinsic strength of color increases with milling time, the speed with which it tends to plateau in the curve varies from one pigment to another.
The problem arises in those bases milling with high proportions of very small pigment particles as they are much more prone to flocculation.
It required an efficient dispersal system to stabilize these small particles so that the intrinsic strength of the color to develop on the surface of the coating. Given this case, the polymeric dispersants are usually much more efficient to stabilize the dispersion of fine particles that resins conventionally used in the coatings industry.…