There are various additives required for UV ink printing, which play a crucial role in the manufacturing, use, transportation, and storage of ink. The following are some commonly used additives and their main functions in UV ink printing:
1. Defoamer
Function: Defoamer is mainly used to prevent and eliminate bubbles generated during the manufacturing and use of ink. It causes bubbles to burst due to its incompatibility with the ink system, high spreading and penetration, and low surface tension.
Application: Commonly used for thin ink varieties with low viscosity, such as UV ink for gravure printing and flexographic printing.
2. Leveling agent
Function: Leveling agent is used to improve the leveling performance of ink layers, prevent defects such as shrinkage, wrinkling, and printing marks, and help improve the gloss of the printing film.
Application: Commonly used leveling agents such as organosilicon acrylate, silicone, etc.
3. Wetting dispersant
Function: Wetting dispersant is mainly used to improve the suspension stability of pigments in ink. It reduces the surface tension of the ink system, allowing the ink to spread on the substrate, while the dispersant adsorbs on the surface of the pigment to generate charge repulsion or steric hindrance, preventing the pigment from flocculation.
Application: Due to the difficulty in distinguishing the effects of wetting agents and dispersants, they are often referred to as wetting and dispersing agents, such as DiGao 685 wetting and dispersing agent.
4. Polymer inhibitor
Function: The anti polymerization agent is used to reduce the thermal polymerization of UV ink during production, transportation, and storage, and improve the storage stability of the ink.
Application: Common polymerization inhibitors include hydroquinone, p-methoxyphenol, and p-benzoquinone.
5. Adhesion promoter
Function: Adhesion promoter is used to improve the adhesion performance between ink and substrate, especially for substrates such as metal, plastic, glass, etc. where ink is difficult to adhere.
6. Thixotropic agent
Function: Thixotropic agents are used to improve the thixotropy of ink, especially in thick ink layer printing, which helps to enhance the clarity of printed products.
7. Wax
Function: Wax is mainly used to change the fluidity of ink, improve water resistance and printing suitability (such as adjusting viscosity), reduce dirt, paper hair and other defects, and improve the smoothness of printed products, making them resistant to friction. In UV ink, wax also plays a role in blocking air and reducing oxygen blocking, which is beneficial for surface curing.
8. Other additives
Anti powder agent: UV ink used for metal coil printing to improve the ink's resistance to pressure processing and prevent film breakage during mechanical processing.
Photosensitizer: Although photosensitizers are not traditional additives, they are an essential component of UV ink, used to trigger the photo curing reaction of ink and improve the drying speed of ink.
In general, there are various types of additives required for UV ink printing, each with its specific functions and effects. The reasonable selection and use of these additives are crucial for ensuring the printing quality and performance stability of UV ink.