Effect of Fineness on Gloss
The fineness of a certain paint is very good, and the surface of the prepared paint film is as smooth as a mirror. When the light is irradiated on the surface of the paint film at a certain angle, the light can be reflected in a certain direction, so that the gloss of the paint film is strong. If the fineness of the paint is not good, greater than the thickness of the first film, the surface of the finished paint film will not be very smooth, so when the light is irradiated, random reflections will occur, which will weaken the amount of light reflected in a certain direction, so that the surface of the paint film The gloss is reduced.
Effect of fineness on weather resistance
If the fineness of the paint is relatively thick, exceeding the thickness of the first film (such as the thickness of the paint film is 23μm, and the fineness of the paint is 25~30μ), there will be pigment particles protruding from the surface of the paint film. When corroded by various external natural factors or under the action of mechanical force, these protruding particles will become corrosion centers or easily fall off from the paint film to form small holes, and finally due to the entry of water damage and other corrosive media. Corrosion is formed, so that the decorative and protective functions are completely lost.
Effect of Fineness on Storage Stability
Our country has a vast territory, and the turnover and storage of corresponding materials are also large. If the fineness of the paint is poor, it means that the pigment is not fully dispersed in the base material during the grinding process, and the pigment particles are not well infiltrated by the base material. If the paint is left for a long time, the pigment will re-flocculate and cause the paint to swell Some pigments even sink to the bottom and form hard lumps, making them unusable and causing waste.
Influence of fineness in electrophoretic paint
At present, from the perspective of electrophoretic paint film, it seems that the fineness has little effect on the paint film, but it is not the case. The pigment in the electrophoretic paint is deposited on the workpiece by dragging the base resin. If the fineness of the paint is too coarse and the pigment particles are large, the resin will not be dragged and will sink to the lower layer, and will not be able to swim on the workpiece. In this way, although the paint liquid added is the same (compared with the fineness), but because the pigment is thick, a part of it is precipitated, so the pigment-base ratio (the ratio of pigment to base resin) participating in the electrophoresis is actually small, and the electrophoresis is actually smaller. The amount of pigment on the workpiece is also reduced, which affects the appearance and performance of the electrophoretic paint film, and also causes partial loss of pigment.
In addition, the fineness of the paint also affects many other performance indicators, such as tinting strength, hiding power, and evenness. Of course, the fineness is not always the finer the better. If something exceeds its limit, it will go to the opposite side. If the pigment particles are small to a certain extent, that is, less than half of the light wave (0.2 μ), the light can pass through the particles without refraction, making the paint film translucent or transparent, and the hiding power will decrease instead.
In addition, the fineness should also be treated differently according to the variety and use. For example, the fineness of the primer is generally thicker than that of the topcoat, and the fineness of the primer is too fine, which will affect the combination of the primer and the topcoat. Generally, the fineness of primer is not greater than 50μ, the fineness of phenolic enamel is not greater than 30μ, and the fineness of amino and alkyd enamel is not greater than 20μ.
