Types and applications of UV inks
1. UV ink for offset printing
Offset printing ink can be used for fine product printing. When ordinary offset printing presses use oil-based ink to print, in order to prevent the top and bottom of the paper from sticking to each other, it is necessary to spray a large amount of dry powder during the printing process and use a large number of partitions during paper delivery to prevent excessive accumulation. Many, because oily ink is not easy to dry quickly.
The characteristic of offset printing ink is that it can achieve instant drying, UV curing can reduce the loss of fine dots, and improve the ink transfer rate of overprinting. When using gold and silver cardboard, polyethylene, coated paper and other non-absorbent materials as the printing carrier The printing of food packaging and cosmetic packaging is easy.
Printing carriers that are more suitable for ink printing include: metal foil, holographic film, etc., such as common cigarette cases, high-end gift boxes, tea outer packaging boxes, various card printing and many other materials that use metal texture as printing The printed matter of the carrier.
The disadvantage of offset UV ink is that its price is 2-3 times that of ordinary oil-based ink. In addition, it also needs special supporting equipment such as ink roller, cleaning fluid, printing plate and so on. Therefore, the printing cost is higher than ordinary offset printing.
2. Flexo printing ink
Compared with water-based and solvent-based inks, flexo UV inks have different components except for the same coloring components and additives. In addition. There is also a slight emphasis on usage. Ordinary water-based flexo printing inks are mainly used for printing paper (corrugated paper, etc.) and reinforced PE bags; solvent flexo printing inks are mainly used for printing plastic film packaging materials, paper cups, etc.; flexo UV inks are mainly used for printing plastic film packaging materials, paper cups, etc. Printing trademark labels, cardboard, etc.
Water-based and solvent-based flexo printing inks mainly use hot air evaporation and drying methods. Flexo UV inks use ultraviolet light emitted by UV lamps to achieve polymerization of oligomers and monomers to cure the ink. It does not contain volatile components, so the ink is in What is left on the printed matter is 100% solid matter, which can form a firm ink film.
Similarly, the abrasion resistance, water resistance and solvent resistance of flexographic UV inks are better than other flexographic inks.
But the disadvantage of flexo UV ink is also a cost issue. The unit price of UV flexo ink is several times the unit price of water-based flexo ink, which lacks price advantage in market promotion and practical application.
3. Screen printing UV ink
If you need to increase the thickness of the ink layer, it is easy to use screen printing UV ink. Ordinary screen printing ink, whether it is solvent volatilization or chemical reaction type, its solid content is about 40%, solvent content is about 60%, while the solid content of screen printing UV ink is 100%, there is no ink solvent volatilization problem. Therefore, the thickness of the ink layer is basically unchanged after curing, of course, it is easy to leave a higher ink layer thickness on the printing carrier. If you use UV ink and common solvent-based ink to print on the same screen, the thickness of the ink layer after UV ink curing is 2-3 times the thickness of the ink layer of common solvent volatile ink, because UV ink does not contain volatile solvents. . Moreover, due to the better adhesion of UV ink, the color quality of the ink layer of the printed matter is also more perfect.
The screen printing UV ink technology is used on the surface of the substrate with metal mirror luster, such as mirror silver card, gold card, foil-plated card board, etc., and its visual effect is obviously more elegant, solemn and luxurious. This type of printing and packaging products are mainly used in high-end, exquisite and unique tobacco, wine, cosmetics, health care products, food, medicine and other fields.
There are many types of screen printing UV inks, which have more special process effects. These inks include: UV wrinkles, UV ice, UV refraction, UV foam, UV frosting, UV varnish, etc.
In the process of screen printing UV ink, factors such as the number of screen meshes, printing pressure, and squeegee angle will affect the printing quality. Therefore, according to different design patterns and requirements, proper adjustment of relevant elements can achieve the desired printing effect.