The methods to improve the adhesion of UV inks can be approached from various perspectives, including adjusting the curing, optimizing printing processes, selecting appropriate materials and formulations, and so on. Here are some specific measures:
1. Increase the power of UV curing lamp：
Increasing the of UV curing on most substrates will enhance the adhesion between UV ink and the substrate. However, it should be noted that over-curing on some substrates may cause the ink to become brittle.
2. Reduce the printing speed：
By reducing the printing speed, more time can be given to the UV ink to fully cure, thus improving adhesion. In addition, using one-way printing instead of back-and-forth printing on UV flatbed inkjet printers can also improve the effect.
3. Red the thickness of ink layer：
Reducing the amount of UV ink used helps to promote its adhesion to the substrate. If the ink layer is too thick, it may appear that surface has cured but the bottom layer has not completely cured, which can lead to the detachment of the ink layer during subsequent processing.
4. Surface treatment：
Appropriatereatment of the substrate surface, such as cleaning, grinding, or using plasma treatment, can significantly improve the adhesion of the ink.2 For specific materials such as acrylic boards, is also crucial to ensure that their surfaces are free of contaminants such as grease or dust.
5. Add adhesion promoters：
Adding specially designed adhesion promot (such as phosphate adhesion promoters, silane adhesion promoters) to the UV ink formulation can effectively enhance the bonding performance between the ink and different substrates.
6. Use primer：
Applying a layer of primer (undercoat) before formal printing can form a base layer on the substrate surface that is more conducive to the adhesion UV ink.
7. Adjust the curing conditions：
It is very important to ensure that the UV ink is fully and properly cured. Incomplete curing is one of the reasons for the decrease in adhesion. Therefore, it is necessary to correctly select the photoinitiator and set the appropriate curing energy.
8. Optimize ink formulation：
In addition to the above methods, the adhesion can also be avoided by adjusting other components in the ink (such as pigments, fillers, and additives) to prevent from negatively affecting the adhesion.2
9. Choose the appropriate substrate and coating：
When facing low surface energy substrates, consider using special coatings to increase roughness, thereby better adhesion.
In summary, improving the adhesion of UV inks requires a comprehensive consideration of factors such as ink formulation, substrate characteristics, and printing processes, and the solution can be found through systematic experimentation and adjustment.