Causes of car paint falling off:
The problem of car paint falling off refers to the loss of adhesion to the substrate due to the cracking of the paint after the car is painted, and under the effect of external force, the polyurethane paint is released in small pieces or on a large scale.
1. Reason:
（1）. The surface layer of the coated object is too bright, which will cause the problem of the paint polyurethane coating falling off.
（2）. Before the construction of the paint project, the metal surface treatment of the substrate is not very good, and there are oil stains, wax, moisture, dust, chemicals, etc., or the metal surface treatment is not carried out immediately after the construction.
（3）. Spray paint or topcoat before the bottom layer is dry, it is very easy to cause the problem of falling off.
（4）. Poor selection of topcoat, high strength of topcoat, and too slippery surface are all caused by the loss of the necessary adhesion between the topcoat and the paint and the problem of falling off.
2. How to avoid:
（1）. Before the construction of the project, the surface layer of the substrate should be treated with a moderate method, and the waste left in the pre-cleaning treatment should be removed.
（2）. The topcoat should choose a type of paint with strong adhesion and wettability.
（3）. The surface of the substrate is too bright to be coated, and appropriate treatment methods should be used before construction.
（4）. After the primer is completely dry, spray paint and top coat.
（5）. It is necessary to strictly implement the engineering construction statistical data provided by the paint manufacturer.
