The preparation process of the Aerosol Paints is mainly physical dispersion and mixing process, including ingredients, pre-dispersion, grinding dispersion, reconcile, color (color) and filter packaging, in which the pigment dispersion is the key to the preparation of paint, pigment dispersion Directly affect the quality of paint and production efficiency.
Dispersion of pigments is a key step in the preparation of paint, pigment dispersion directly affect the quality of paint and production efficiency. The dispersion of the pigment in the paint is a complex process involving at least three processes of wetting, grinding and dispersing the pigment.
The surface of the pigment particles used for the production of paint, usually with water and air, the gap between the particles will be filled with air. Therefore, in the dispersion of the pigment, the first is the moisture content of the pigment surface, the air is replaced by the paint, that is, the pigment is impregnated with the resin solution or the solution (i.e., the paint) containing the wetting and dispersing agent.
The lower the viscosity of the paint, the faster the wetting of the pigment. For solvent-borne Aerosol Paintss, the surface tension of the paint is usually less than the surface tension of the pigment, so the pigment is easy to soak. For water-based paint, the surface tension of water is generally more than the organic paint surface tension, wetting difficulties, so need to add wetting agent to speed up the wetting of the pigment.
In the paint industry, this process is usually done under grinding conditions, where grinding is primarily shear. The so-called grinding is not grinding the original particles of the pigment, but the pigment aggregates are broken and dispersed in the paint. The greater the viscosity of the paint,Aerosol Paints the greater the shear force, is conducive to grinding, appropriate, appropriate amount of wetting and dispersing agent in this period can play a role in improving the grinding efficiency, can speed up the depolymerization of pigments.
After the pigment is dispersed, the surface energy of the pigment particles increases and tends to converge with each other. Therefore, the pigment dispersion process has been depolymerized pigment particles is also a very important part of the link, otherwise the paint will be re-flocculation during storage and construction, resulting in lower quality paint.
Pigment in the paint dispersion system,Aerosol Paints mainly through the charge stability and three-dimensional protection of the two mechanisms to achieve stability. The former method is to add some surfactants or inorganic dispersants, such as polyphosphates or hydroxylamine, etc., the latter method is in the solvent-based Aerosol Paints, adding some long-chain surfactants, can form 8 ~ 9nm adsorption Floor.
In fact, the three processes of wetting, dispersing and stabilizing the above-mentioned pigments are not completely separate, and sometimes occur simultaneously and alternately. For the paint dispersion system,Aerosol Paints the wetting is the foundation, grinding is to more fully wet, the stability of the pigment after dispersion is the ultimate goal.