Orange peel effect during the drying of one-sided gold paint severely affects the smoothness and gloss of the paint film, reducing its decorative effect and protective performance. The orange peel effect is essentially due to insufficient leveling caused by uneven surface tension during the paint film drying process. Its formation is closely related to factors such as solvent evaporation rate, application viscosity, ambient temperature and humidity, spraying process, and material selection. Optimizing the process requires comprehensive control from multiple dimensions; the following analysis focuses on key aspects.
Balancing the solvent evaporation rate is crucial to avoiding orange peel. Excessive solvent evaporation leads to a sudden drop in the surface temperature of the paint film, a rapid increase in paint concentration, and the generation of convection vortices within the film, resulting in a rough and uneven surface. This can be controlled by adjusting the thinner formulation, such as using a high-boiling-point solvent in high-temperature environments or adding a slow-drying agent to extend the leveling time. It is also important to ensure that the solubility and evaporation gradient of different solvents are matched to avoid localized differences in drying speed due to solvent stratification.
Precise control of application viscosity directly affects the leveling properties of the paint film. If the viscosity is too high, the paint will have poor flowability and be difficult to spread evenly on the substrate surface; if the viscosity is too low, it may cause sagging or metallic pigment settling. In practice, the viscosity needs to be adjusted according to the ambient temperature and paint type. For example, in hot summer weather, the amount of thinner can be increased appropriately, and the viscosity should be monitored in real time using a viscosity cup. In addition, the paint must be thoroughly stirred to avoid metallic pigment sedimentation or clumping; if necessary, a filter with a mesh size of 400 or higher should be used to filter impurities.
Optimizing the spraying process is crucial to reducing orange peel. The spray gun operation must maintain stable air pressure, a suitable distance, and be perpendicular to the substrate, with a uniform movement speed to avoid localized areas of excessive or insufficient thickness. For example, using a "half-gun, half-gun" technique ensures that the edge of each spray precisely covers the area previously sprayed, ensuring uniform paint layer thickness. Simultaneously, the substrate must be thoroughly treated before spraying, including sanding, cleaning, degreasing, and applying a matching sealing primer to enhance adhesion and wetting. The presence of orange peel or impurities on the substrate surface will directly affect the leveling effect of the topcoat.
Controlling ambient temperature and humidity is crucial for the paint film drying process. High temperatures accelerate solvent evaporation, causing the paint film to dry before it has fully leveled; while excessive humidity can cause condensation, damaging the surface tension of the paint film. Therefore, a dry, well-ventilated environment should be chosen for application, and temperature and humidity should be controlled using air conditioning or dehumidification equipment. For example, during summer application, the drying room temperature can be lowered to below 30℃ to avoid orange peel effect caused by excessive temperature. Furthermore, application should be avoided in windy or humid weather to minimize interference from external factors on the paint film drying process.
Material selection and compatibility are fundamental to process optimization. High-quality one-sided gold paint requires excellent leveling properties and anti-orange peel performance, while the thinner and hardener must be strictly compatible with the paint. Using a thinner with insufficient dissolving power will lead to poor leveling properties; while excessive hardener addition or prolonged storage may cause uneven film shrinkage. Therefore, it is necessary to select compatible products according to the paint instructions and strictly control the addition ratio and application time.
The synergistic design of multi-layer coating processes can further improve paint film quality. For example, in metallic paint application, the drying times of the base coat and clear coat must be properly coordinated. Applying clear coat before the base coat is completely dry may hinder solvent evaporation, leading to orange peel or undercoat defects; conversely, an excessively thick clear coat may cause cracking due to internal stress. Therefore, the drying time for the wet-on-wet process must be strictly adhered to, ensuring each paint film is fully leveled before proceeding to the next step.
Process optimization must be integrated throughout the entire application process. From substrate treatment, paint mixing, spraying operations to drying environment control, each step requires strict control. By comprehensively adjusting solvent evaporation rate, application viscosity, spraying process, ambient temperature and humidity, and material compatibility, the orange peel effect during the drying of one-sided gold paint can be effectively avoided, ultimately resulting in a smooth, evenly glossy, high-quality paint film.
