Reasons for car coating falling off and preventive measures
The detachment of the lacquer surface means that as the paint film is cracked, the adhesion between the lacquer surface and the surface of the car body or the new and old lacquer surface is lost, causing the surface of the lacquer surface or the fish phosphor sheet to fall off; or the attachment between the lacquer surface and the bottom surface thereof. The force is completely lost, causing the paint surface to fall off in a large area. Last time, Xiaobian has shared the issue of how to prevent the appearance of particles in the automotive electrophoretic paint film. Then this time, the electrophoretic paint manufacturer will fly to introduce the cause of the car coating peeling off and preventive measures.
(1) The surface before painting is not clean thoroughly. The surface to be sprayed is wet or contains moisture, oil, surface oxides and dust. The chemical substances after cleaning the surface are not cleaned; the paint should be removed.
(2) The surface to be sprayed is too smooth, resulting in low adhesion.
(3) The paint layer of the same nature is not used in the front and back paint layers, or the primer paint film is too hard, so that the paint surface is not easy to bond.
(4) The temperature in the paint booth is too high, or the baking time is too long or too short.
(5) Spray a paint when the paint layer is too thick or the previous layer of paint is not dry.
(6) pulverization or staining between lacquer layers, hindering the combination of lacquer layers (painting in areas where moisture is condensed or where chemical smog is large, it is easy to cause the lacquer surface to fall off in a large area).
(1) Before painting, the surface to be sprayed should be carefully cleaned to make the surface to be sprayed clean and dry.
(2) For an excessively smooth surface to be sprayed, sandpaper should be used to make it have a certain roughness.
(3) Strictly control the temperature and time of the paint, strictly in accordance with the technical conditions of the paint variety.
(4) The matching of the paint layer must be considered and its bonding force should be enhanced. The matching of the coating should meet certain criteria, at least have a certain degree of compatibility. Generally, the solvent of the outer coating should be slightly stronger than the primer, which can weakly swell the underlying coating film, so that it can be combined without being free. Mix two different paints together.
(5) When painting the old lacquered surface with severe pulverization, it is necessary to add a reinforcing layer once again. For a particularly hard epoxy lacquer surface, it is difficult to soften it with ordinary solvents, and it must be treated and then repeatedly painted to adhere. Firm.
(6) When the vinyl chloride paint is sprayed on the surface to be sprayed on which the primer has been sufficiently dried, the first layer of the perchloroethylene paint film should not be completely dried and then sprayed down, so as to strengthen the bonding force between the paint layers. Otherwise, it may cause peeling or peeling off due to poor compatibility between paint layers.
(7) In chemical smog or in the wild environment, quick-drying paint should be used to shorten the painting time. In the wet environment, the surface water vapor should be dried before painting, or the paint film should be dried before painting.
The contents mentioned above are the reasons for the falling off of automotive paints and the preventive measures. I hope to help everyone.