⑴Poor adhesion
For interior trim coatings, there are two main types of adhesion failure: poor adhesion between the primer and the substrate, and poor adhesion between the primer and the topcoat. The main causes of failure are related to the compatibility between the paint films and the pretreatment of the substrate. In addition, factors such as the production environment and process are also important determinants of paint film adhesion.
⑵Bubbling
The coating peels away from the substrate (base material or underlying coating) due to localized loss of adhesion, causing the coating film to form circular bulges. The bubbles may contain liquid, steam, other gases, or crystalline substances. Of course, even the best paint film can be penetrated by moisture. When moisture penetrates the paint film, it may generate sufficient pressure to weaken the adhesion between different paint layers or the overall adhesion of the coating to its substrate, resulting in the formation of moisture-containing bubble-like protrusions. The primary causes of bubbling are: ① inadequate pretreatment of the paint film; ② insufficient coating thickness or improper use of diluents; ③ the use of coatings containing components that readily react with moisture.
⑶Chalking and discoloration
The surface of the coating film exhibits discoloration or loose powdery particles due to the degradation of one or more paint bases and the decomposition of pigments. The main causes of chalking and discoloration are: the coating film ages during use due to the effects of ultraviolet rays, oxygen, and moisture, causing the paint base to break down and expose the pigments. Users should select automotive coatings with excellent weather resistance based on the conditions of use.
⑷Poor corrosion resistance
The coating has poor corrosion resistance, mainly manifested in defects such as corrosion spots, radial stripes, and exposed copper layers after testing. The poor corrosion resistance of the coating is mainly related to the electroplating process. For example, poor pretreatment before electroplating can cause defects such as pitting and pits on the surface. Therefore, strict control of the production process is required during electroplating.
⑸Bubbling and cracking of the plating layer
If there are tiny bubbles between the plating layers or between the plating layer and the substrate, when external temperatures change, these small bubbles will expand, causing separation between the plating layers or between the plating layer and the substrate. Additionally, if the plating layer is not subjected to proper stress relief treatment after electroplating, changes in external environmental conditions may also cause cracking in areas where the plating layer is concentrated, such as at bends.
In summary, with the development of automotive lightweighting, the application of plastics in car bodies will gradually expand, and the requirements for interior component surface treatment technology and product quality will also gradually increase. Therefore, improving and enhancing the quality of automotive interior plastic components is a long-term development project.
Busman excels as a trusted expert in automotive plastic interior and exterior components. With advanced molding tech and strict quality control, we deliver durable, stylish parts-from dashboards to bumpers. Customized solutions meet diverse vehicle models' needs, blending functionality with aesthetic appeal. Partner with Busman for reliable automotive plastic excellence.