I. Introduction
In UV coating processes, adhesion issues of UV-curable coatings are a common and critical factor affecting coating quality. Good adhesion not only ensures the integrity and aesthetics of the coating but also enhances its protective performance for the substrate. How to improve the adhesion of UV inks has become a core focus of industry technical research. As a professional enterprise deeply involved in the UV coating field, Shenzhen Zicai Technology Co., Ltd. (hereinafter referred to as “Zicai”) has accumulated extensive practical experience in solving adhesion problems. This article will explore the possible causes affecting UV coating adhesion and propose corresponding feasible solutions.
II. Causes Affecting Adhesion
(1) Factors Related to Primer
- Hardness: Excessively hard primer results in a smooth surface, making it difficult for the topcoat to adhere.
- Film Thickness: Overly thick film layers can generate internal stress and may not dry completely, affecting interlayer bonding.
- Two-Component Baking Time: Excessive baking time increases cross-linking density, reducing surface flexibility and hindering topcoat penetration.
- Aluminum Powder Content: Excessive aluminum powder in aluminum powder paint alters surface properties, leading to uneven adhesion.
(2) Factors Related to UV Topcoat
- Resin and Monomer Characteristics: Insufficient adhesion or high shrinkage stress can cause interlayer gaps.
- Film Thickness: Overly thick film layers can generate internal stress and incomplete curing, affecting bonding.
- Solvent Effects: Weak solubility or rapid evaporation prevents sufficient swelling of the primer surface.
- Surface Tension: High surface tension results in insufficient wetting, leading to defects such as bubbles.
- Formula Design: Imbalanced component ratios affect overall adhesion performance.
III. Solutions
(1) Optimization of Primer Issues
- Adjust Hardness: Reduce primer hardness by adjusting resin types or adding plasticizers in the formula.
- Control Film Thickness: Optimize spraying parameters (pressure, distance, etc.) to ensure uniform and appropriate film thickness.
- Two-Component Curing Control: Determine the optimal baking time through experiments to avoid excessive cross-linking.
- Aluminum Powder Content Regulation: Reasonably control the aluminum powder ratio while ensuring appearance.
(2) Improvement of UV Topcoat
- Select Compatible Products: Choose specialized topcoats for different primers.
- Adjust Solvent Parameters: Optimize solubility and evaporation rate to enhance swelling effects on the primer surface.
- Control Film Thickness: Adjust equipment and process parameters to ensure moderate film thickness.
- Optimize Formula: Add adhesion-promoting monomers to improve the compatibility of resins and other components.
IV. Conclusion
UV coating adhesion is influenced by multiple factors related to both primer and topcoat. By adjusting hardness, film thickness, curing time, and optimizing topcoat formulas, adhesion can be effectively improved, ensuring coating quality. 姿彩科技 (Zicai Technology) has found through practical experience that continuous testing and optimization are required in actual production to adapt to technological advancements, and the company has developed advanced solutions based on these findings.
Post time: Jun-02-2025
