Filling-type paint has the characteristics of high content of pigment and filler, good air permeability of paint film, strong filling ability on the surface of putty, and the residual moisture and gas in the putty layer can be the same as the solvent in middle paint. And volatilizes out, can eliminate blistering problem completely.
The sealed medium paint is the last middle layer before the top coat. Its pigment content is slightly higher than the top coat. Due to the high content of powder in the putty layer and fill-in coating film, the paint film is loose, although it is easy to be polished, it is easy to make the top coat penetrate into the base layer, which affects the gloss, distinctness and fullness of the top coat. The use of the middle coating is mainly to increase the density of the bottom layer, so that the top coat does not penetrate into the bottom layer, so that the top coat maintains its proper decorative effect.
The above kinds of paints are used together, although a painting process is added, but the paint film is not blistering and the overall vehicle painting quality is improved.
Bus factory in the selection of putty, in the paint should not only emphasize the sanding is good, its fineness; in particular, the middle coating and strength should also be required. The middle coating should have anti-overcoat paint permeability, easy sandability, strong adhesion to the upper and lower layers, and good physical and mechanical properties and resistance to stone impact. Some passenger car factories are not careful enough about the middle coating construction process, and use rougher water sandpaper to polish it. This seems to be very smooth from a large area, but it leaves a deep sand pattern on the middle coating. I hope that the finish will cover the sandpaper. Pattern. Of course, the leveling property of the topcoat is better, the sandpaper pattern is lighter, and the middle coating is made more carefully. Using the same topcoat can significantly improve the coating quality of the passenger car.
The topcoat has a long body and a variety of materials; the body has aluminum plates, galvanized plates, painted steel or aluminum frames, etc., which is relatively small compared to the number of carts, so it is impossible to go to the phosphating and electrophoresis of the whole vehicle like a car. At the same time, aluminum plates and special galvanized plates are used for the exterior panels of automobile bodies, and there is no need to phosphatize or electrophorese the entire vehicle. Due to the variety of colors required by customers, topcoats for bodywork cannot be topcoated.
Therefore, the topcoat for passenger cars is basically a low-temperature refinish paint.
Topcoat is the key product to improve the overall exterior decoration level of passenger cars. It is the final coating used in multi-layer coating of automobiles and directly affects the exterior decoration performance, durability and weatherability of automobiles. Therefore, paint manufacturers and automotive paint manufacturers have strict requirements on product performance assessment and quality control. In the past, DE gloss was used as the sole criterion for evaluating the construction effect, and it was considered that the gloss of @F or more was acceptable.
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