Global demand for UV printing is increasing. Especially in Europe, America and Latin America. According to European equipment manufacturers, the annual growth rate of UV printers will reach 7%, the annual growth rate of UV drying devices will reach 10%, and the growth rate of UV ink and mineral oil will reach 14%. According to the largest U.S. ink maker, the local market is expected to see an annual increase in the consumption of UV inks and mineral oils of around 15 percent. This figure is similar to the year of ink consumables in the traditional offset market.
The application fields of UV technology are also expanding, including labels, plastics, multi-purpose sheet-fed paper, tape printing, etc. Especially in the field of label printing, UV printing has shown an unprecedented growth trend. High-speed flexo labels, shrink wrap, thermoforming wrap effect label printing, etc. all use UV technology. This article will focus on the huge promotion of UV technology to label printing from four aspects: high-speed curing technology, low thermal effect, wide personality, and high solid content.
1. High-speed curing
It has been less than 20 years since the flexographic printing process was introduced to China, and domestic printing companies have used flexographic printing labels for a relatively short period of time. Even today in the 21st century, domestic label printing mostly adopts letterpress printing, and the adoption of Flexo printing is still in its infancy. However, for developed countries such as Europe and the United States, their label printing market is very mature, about 90% of labels use flexo printing in China, although the Flexo printing process is still very young in label printing, these labels Flexo printing methods have strong 's physical strength. According to industry statistics, China's label market is currently rising at a rate of about 30% per year. With the expansion of the label market, the rise of the label printing industry is also triggered.
There are two main reasons why flexo printing has become the mainstream process in label printing. First, flexographic printing is a relatively environmentally friendly printing method. The ink is non-toxic and tasteless, and meets international environmental requirements. At present, many large multinational companies are becoming more and more strict with the packaging of their products, basically printing product packaging by soft printing. Domestically, pharmaceutical and food companies have become the main source of customers for soft label printing in my country. Second, soft printing has more advantages than other printing methods. For example, high color saturation, great for normalization, spot color representation, combined printing, etc.
However, the printing speed of flexographic printing machines is usually maintained above 100m/min, which is 2 to 3 times that of the most commonly used letterpress printing machines for label printing in my country. In such a fast printing environment, UV curing efficiency becomes the key to printing success or failure. The general infrared drying process cannot meet the requirements. It's a huge baking facility. The long bake road is a printing company's nightmare. Using the UV drying curing process, the ink can be cured within seconds after printing, which greatly improves the productivity. The baking and drying process can be omitted, the drying equipment is simple, and the space is saved, which is completely suitable for the production of high-speed Flexo labels.
2. Low thermal effect
Heat shrinkable film label is a film label printed on plastic film or plastic tube with special ink. When heated (about 70°C) during the labeling process, the shrinkable label will shrink rapidly along the outer contour of the container and stick to the surface of the container. Heat shrinkable film labels mainly include shrink sleeve labels and shrink wrap labels. The shrink sleeve label is a cylindrical label made after printing with a heat shrinkable film as a device. It is convenient to use and is very suitable for special-shaped containers.
As a part of the label market, heat shrinkable film labels are currently growing rapidly, and the mayor/market share continues to expand. The annual growth rate is expected to be around 15%, which is much higher than the general label market of around 5%, with great development potential. It has become a bright spot in the label printing industry. It is expected that the domestic heat shrinkable film market will grow by more than 20% in the next five years.
The production of heat shrinkable film labels is very demanding on process technology. Especially when printing heat shrinkable film, how to adjust the drying temperature is more important. For general water-based and solvent-based inks, if the drying temperature is too high, the material will shrink thermally. If the temperature is too low, the ink will not dry completely, and eventually there will be problems such as adhesion and dirty back, so the process is quite complicated and the rejection rate is high. For UV curing and drying technology, under the action of ultraviolet energy, the polymer material instantly forms a network cross-connection, and the ink is quickly cured without affecting the temperature of the printing material. The unique cooling and hardening system is very suitable for the production of thermal material labels.
Recently, M has launched UV LED inkjet printer. This product completely uses UVLED to dry printing ink, pure UV drying produces little heat, and is also suitable for printing on thermal media such as acrylic plastic.
3. Wide range of substrates
In recent years, the printing volume of global cultural paper has continued to decline, but label packaging printing is still increasing. With the widespread use of label supplies in life, polyethylene (PE) film, polyvinyl chloride (PVC) Special materials such as film, polypropylene (PP) film, metal foil and non-absorbent. The surface of these materials is dense and does not absorb ink. If printing with ordinary solvent-based ink, it requires a certain drying time. Generally, other additives need to be mixed in powder, dryer device or ink. UV ink has no such troubles at all. For example, Ekval's Evona UV inkjet press claims that, in addition to air and water, as long as the printed material can enter the UV inkjet press, it can print directly. Applicable printing materials include paper, film, PE, PET, PP, OPP, BOPP, PVC, Agaric glass, plate, ceramic tile, etc.
4. High solid content
The high solid content of ordinary solvent-based ink is about 40%, and the high solid content of UV ink after curing is close to 100% of that of ordinary ink. The printing ink layer is thick and bright in color, suitable for label printing. By controlling the thickness of the ink layer, the grating effect, embossing effect. Recently, the UV stereo grating ink UV-1278N has been launched in China. It uses the characteristics of high solid content and high solid content of the ink to print the three-dimensional grating film. This ink is colorless and transparent, quickly cured by ultraviolet rays, the cured film does not turn yellow, and has good adhesion , good toughness. Different from the traditional thermoforming agent three-dimensional grating process, the new process adopts the screen printing method to print ink on the "transparent diaphragm" of the packaging machine to directly form the column grating pattern. In addition, the three-dimensional grating ink can be directly printed on the printed matter to form a three-dimensional pattern, and the pattern can also be selectively printed to make a partial three-dimensional painting. Using this ink to print the lenticular diaphragm can greatly reduce the production cost and improve the productivity. The printing equipment can be PVC, PC, PET or transparent plastic films, such as paper, metal, glass, ceramics, etc.
NAMO's VersaUV LED is the world's first UV inkjet printer using safe, low-heat LED lamps, which can not only print yellow, magenta, blue, and black in 5 colors and glosses, but also with excellent print quality. This machine is mainly suitable for one-off packaging printing and short-board label printing, which can perfectly express "very rich special effects", whether it is high-gloss effect or texture effect, and can even reproduce the texture of artificial leather and crocodile skin. difference.
In addition, UV technology is also very popular in the field of film printing. At present, the label industry generally adopts the UV polishing process to replace the surface coating, and the non-film polishing is realized on the wheel conversion label machine. That is to say, the gloss on the UV is evenly applied to the surface of the graphic immediately after printing. For flexographic prints using water-based inks, the polishing process is compared with traditional drying equipment, which requires hot stamping of ordinary ink first, and then printing. The disadvantage is that the printing pattern design is limited. On equipment with UV drying device, you can print first and then perm. After the ink dries quickly, you can perm on the ink. The perm pattern can be arbitrarily designed and is not limited by ink. It is suitable for S advanced label printing.
In short, UV technology does not require a heat source, pure ultraviolet cold hardening, suitable for the production of heat-sensitive labels. Fast curing (cure time of less than a second), high productivity and high process production can reduce the warehouse of raw materials and finished products. The overall curing system of UV technology is a solvent-free system, 100% solvent-free formula, suitable for the production of special effect labels, no VOC volatile organic compounds, and fully adapt to environmental pollution regulations. It is believed that in the near future, technology will become the first choice for more and more label manufacturers.