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What are the reasons for the incompatibility of pigment coatings?

Update:There are many reasons for insufficient compatibility. Two important reasons for incompatibility between solvent-based a...
Summary:22-11-2021
There are many reasons for insufficient compatibility. Two important reasons for incompatibility between solvent-based and water-based coatings are as follows:





Solvent-based base paint is not compatible
Due to the low polarity of the solvent-based base paint, the electrostatic shielding stabilization effect only plays a minor role. The pigment particles are stabilized and not flocculated mainly by the adsorption layer. The decisive factor is the thickness and integrity of the polymer.
Modern pigment concentrates are the best combination of color strength and viscosity. Low viscosity can be obtained by controlling the additive amount of additives, but it is not enough to stabilize the pigment. For difficult-to-wet pigments, such as Hostaperm Rosa E (PR 122), when little or no polymer is adsorbed on certain parts of the pigment surface, these conditions will occur, the pigment flocculates, the color development power decreases and the index value increases.

Water-based base paint is not compatible
When producing water-based latex paints, be careful when adding wetting and dispersing additives to achieve the maximum viscosity reduction effect. In this case, the pigment particles are only coated by the polymer.
If a pigment concentrate containing a relatively high concentration of wetting and dispersing additives is used for color mixing, these additives will be rearranged, the pigments will no longer be sufficiently stabilized, flocculation, and the index value will also deteriorate.