How to solve the poor compatibility between emulsion paint and tinter?

To color latex paint with water-based color paste, first of all, it is necessary to have good compatibility between water-based color paste and latex paint. If the compatibility is not good, it will cause flocculation, color floating, flowering, coloring strength decrease, hue shift, fineness increase, gloss decrease, paint stability deterioration and so on. The best way to judge the compatibility is to do the finger research experiment. The operation method is: add the largest amount of color paste to the latex paint, stir and mix evenly, apply it on the scraping paper, and use it before it is dry. Wipe with your fingers for about 1 minute, and observe whether there is a color difference between the wiped part and the unwiped part after it dries. If there is no color difference, the compatibility is good. If there is color difference, it means that there is flocculation of the pigment, and the wiped part is de-flocculated due to the action of external force. Compatibility can also be tested by other methods, such as:

① Observe the hue change, flocculation will make the hue red shift;

② Measuring fineness;

③Flow coating experiment.

There are generally two possible reasons for poor compatibility. One is poor dispersion stability of the color paste, which is prone to flocculation, floating color, and blooming. This requires users to choose high-performance color paste with good dispersion and stability. . Another reason may be that the amount of wetting and dispersing agent in the latex paint is insufficient or inappropriate. After the color paste is added, the pigment and filler particles in the latex paint rob the dispersant on the surface of the color paste pigment, causing the color paste pigment to flocculate. It is necessary to increase the amount of dispersant in the latex paint, or change the type of wetting and dispersing agent until the compatibility test is passed.

It is worth mentioning that when the color paste has good compatibility with the latex paint, after the color paste is added to the latex paint, it generally only needs to be stirred evenly with a mixer or a vibrating machine, and sanding or high-speed dispersion is no longer required. Under the conditions of sanding or high-speed dispersion, high shear force will further disperse the pigments and fillers in the latex paint to form a new surface. The new surface needs to compete for the dispersant to stabilize, which may cause the pigment dispersant in the color paste to be destroyed. Take away and flocculate.