In the process of paint production and application, we often meet the problem of floating color, when the paint appears floating color, the color and the standard board produce color difference, color mixing becomes very difficult, it is a waste of paint and color mixing is not accurate, at the same time, the paint can be opened very bad, and paint dry after the application of film color deviation and it is difficult to paint uniform. One of the dynamic pigment separation phenomena: pigment in the horizontal direction separation barriers so that uneven color coating film and the emergence of flowered. Floating color is the color changes in the vertical direction, paint in the film and drying process of one or more pigment separation, a pigment floating to the surface, another pigment in situ or sink to the bottom.
How to observe and judge the phenomenon of flowered hair in the laboratory?
There are two ways to start: static floating in the tank: the phenomenon of one or more pigments in the tank separating and emerging on the surface after the paint has been evenly dispersed and left in the tank for a period of time, for example, after being stored for a period of time, after opening the can, the inner surface of the can appears black, phthalocyanine blue or white. Dynamic floating color: the phenomenon of pigment particle separation during the drying process is called dynamic floating color, dynamic floating color pigment separation two cases: one is uneven color on the surface of the film, the other is the film floating color good surface color, but the surface and the bottom color is different. To identify floating colors, first pour or coat the paint on a glass plate or black-and-white cardboard. When leveled, rub the fingers until the film begins to thicken and the pigment particles no longer move and separate, if the coating has floating color, the color difference between the unrubbed surface and the rubbed surface exists, the pigment is easy to separate and the silk stripe appears during the rubbing process, and the surface of the coating after drying will appear edgy and edgy patterns, the degree of discoloration of finger rubbing varies with the condition of finger grinding. The length of rubbing time or the weight of rubbing action and the drying speed of coating film have great influence on the degree of color change. There are many factors affecting the floatation of coatings, such as the difference of particle size of pigments and fillers, the difference of surface tension of various substances in the system, and the hydrophilicity and lipophilicity of various substances.