Common problems and analysis in the application of paint color paste
The color paste is added to the paint, and the color floats on the surface
Reason:
(1) The surface tension difference between the color paste and the paint is too large. Paints generally use anionic or ionic polyelectrolyte dispersants, while color pastes generally use non-ionic or partially anionic dispersants, so that white pigments and colored pigments adsorb different wetting dispersants on the surface and have different surface tensions.
(2) The color paste is not compatible with the paint. The emulsifier outside the emulsion particles is not compatible with the surfactant outside the color and filler particles, causing pigment flocculation.
(3) The hydrophilic-lipophilic balance value between the color paste and the paint does not match. The surface tension of the lipophilic end of the lipophilic substance is small and it is easier to float to the surface.
(4) The influence of thickener. Some pseudoplastic associative thickeners have a strong affinity with surfactants with large HLB values, causing them to desorb on the surface of the pigment, resulting in aggregation and flocculation of the pigment, and resulting in floating color.
Selecting appropriate wetting and dispersing agents, adjusting the surface properties of the particles, and adjusting their movement balance are the methods to control floating color. For example, if the colored pigment flocculates, floats white, or the pigment flocculates and floats, wetting and dispersing agents can be used to alleviate flocculation, improve the surface properties of the particles to prevent or control floating color, and several floating color phenomena can be transformed into each other in the process of controlling floating color to control floating color. If the floating color is the color of the color paste, it means that the HLB value of the paint is large and it is relatively hydrophilic. Several floating color phenomena can be transformed into each other in the base process to control floating color. If the floating color is the color of the color paste, it means that the HLB value of the paint is large and it is relatively hydrophilic. In the preparation process of the base paint, add lipophilic low-polarity additives to reduce the HLB value of the paint; if the floating color is white, it means that the HLB value of the paint is relatively small and it is relatively lipophilic. In the preparation process of the base paint, add hydrophilic additives to increase the hydrophilicity of the paint.