The hottest UV technology will become the first ch

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UV technology will become the first choice for more and more label printing enterprises

the demand for UV printing is rising all over the world, especially in Europe, the United States and Latin America. According to European equipment manufacturers, the annual growth rate of UV models will reach 7%, that of UV drying devices will be 10%, and that of UV inks and varnishes will reach 14%. According to the statistics of the largest ink manufacturer in the United States, the consumption of UV inks and varnishes in the local market will increase by about 15% every year, which is almost 10 times the annual growth rate of ink consumables in the traditional offset printing market

the application fields of UV technology are also expanding, such as label, plastic, multi-functional sheet fed and tape printing. Especially in the field of label printing, UV printing reflects an unprecedented growth trend. UV technology is used in high-speed flexographic labels, shrink sleeve packaging, thermoformed sleeve special label printing, etc. This paper will focus on the great promotion of UV technology to label printing from four aspects: high-speed curing, low thermal effect, wide substrate and high solid content

1. High speed curing

flexographic printing process has been introduced into China for less than 20 years, and the time for domestic printing enterprises to use flexographic printing to print labels is relatively short. Even in the 21st century, letterpress printing is still mostly used in domestic label printing, and the use of flexographic printing is still in the preliminary stage. However, for developed countries such as Europe and the United States, their label printing market has been very mature. More than 90% of labels are printed by flexographic printing. In China, although the flexographic printing process is still young in label printing, this label flexographic printing method has a strong momentum. According to industry statistics, the current label market in China is rising rapidly at a rate of about 30% every year. The expansion of the label market has also contributed to the rise of the label printing industry

flexographic printing has become the mainstream process of label printing mainly in two aspects: first, flexographic printing, as a relatively environmentally friendly printing method, the ink is non-toxic and tasteless, which meets the international environmental protection requirements. At present, many large multinational companies are increasingly strict with product packaging, and basically have adopted flexographic printing to print product packaging. For China, pharmaceutical and food enterprises have become the main source of customers for label flexo printing; Second, flexographic printing has more advantages than other printing methods in label printing, such as higher color saturation, very suitable for standardization, outstanding spot color performance, more convenient to realize combined printing, etc

however, the printing speed of flexographic printing machine can usually be maintained at more than 100m/min, which is times that of the relief printing machine most commonly used in label printing in China. In such a high-speed printing environment, UV curing efficiency has become the key to the success or failure of printing. Ordinary infrared drying technology is far from meeting the requirements. The huge baking equipment and lengthy baking path are simply a nightmare for printing enterprises. Using UV drying and curing process, the ink can be cured within a few seconds after printing, which significantly improves the production efficiency, and can also omit the baking and drying process. Moreover, the drying equipment is simple, saves space, and is completely suitable for the production of high-speed flexo labels

2. Low thermal effect

heat shrinkable film label is a kind of film label printed on plastic film or plastic pipe with special ink. In the process of labeling, when heated (about 70 ℃), the shrinkable label will quickly shrink along the outer contour of the container and cling to the surface of the container. Heat shrinkable film labels mainly include shrink sleeve label and shrink surrounding label. Shrink sleeve label is a cylindrical label made of heat shrinkable film as the base material and printed. It has the characteristics of convenient use and is extremely suitable for special-shaped containers

heat shrinkable film label is a part of the label market, which is currently in rapid growth, and its market share is expanding. It is estimated that the annual growth rate is about 15%, which is much higher than the annual growth rate of about 5% of the ordinary label market. It has great development potential and has become a highlight of the label printing industry. It is predicted 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 has high requirements for process technology, especially when printing heat shrinkable films, how to control the drying temperature is very important. For ordinary water-based and solvent based inks, if the drying temperature is too high, the material will shrink; If the temperature is too low, the ink is not dried thoroughly enough, resulting in problems such as adhesion and dirt on the back. Advanced textile materials, therefore, the process is quite complex and the scrap rate is high. As for the UV curing and drying technology, under the action of UV energy, the ink makes polymer materials form cross-linking instantly, and the ink solidifies rapidly, which has no effect on the temperature of printing materials. The unique cold curing system is very suitable for the production of thermal material labels

recently, Mimaki company released a desktop UV LED inkjet printer uJf 3042, which completely uses UV led to dry the printing ink. Pure UV drying hardly generates any heat, and it is even suitable for printing on thermal media such as acrylic plastic

3 wide range of substrates

in recent years, the total amount of cultural paper printing in the world has been declining, but label packaging and printing is still growing, and label supplies are everywhere in life. With the wide application of labels, more and more printing materials are used, such as polyethylene (PE) film, polyvinyl chloride (PVC) film, polypropylene (PP) film, metal foil and non absorbent special materials. The surface of these materials is dense and does not absorb ink. If ordinary solvent based ink is used for printing, it needs a certain drying time. Usually, it also needs to use powder spraying, drying rack device or add other additives to the ink, and UV ink has no such trouble at all. For example, Agfa's aibona UV inkjet printer claims that in addition to air and water, as long as the printed material can be put into the UV inkjet printer, it can be directly sprayed. Applicable objects such as paper, film, PE, pet, PP, OPP, BOPP, PVC, acrylic glass, wood, ceramic tiles, etc

4 high solid content

the solid content of general solvent ink is about 40%, while the solid content of UV ink after curing is close to 100% times that of general ink. The printing ink layer is thick and bright, which is very suitable for label printing. At the same time, grating effect and relief effect can be achieved by controlling the thickness of the ink layer

UV solid grating ink UV 1278n is the latest one launched in China, which is used to print solid grating films by taking advantage of the high solid content of the ink. The ink is colorless and transparent, and UV light cures quickly. The cured film is not flooded with waste plastic. It becomes an environmental friendly 3D printing material, which is highly promoted, with good adhesion fastness and toughness. Different from the traditional process of preparing solid gratings by hot pressing, the new process uses silk printing method to print ink on the packaging machine 'target'=_ Blank> a cylindrical grating pattern is directly formed on the transparent diaphragm; The three-dimensional grating ink can also be directly printed on the printed matter to form a three-dimensional pattern, and the pattern can also be selectively printed to make the local three-dimensional. The three-dimensional effect of the printed pattern is shown by the R & D team of Mingxinda group, which adopts internationally advanced extrusion and injection molding equipment, which is not comparable to the hot pressed grating plate, opening up a new method for three-dimensional printing, "Wardle explained. Printing grating film with this ink can greatly reduce the production cost and improve the production efficiency. The printing substrate can be transparent plastic film, such as PVC, PC, pet, paper, metal, glass, ceramics, etc

versa UV LED launched by Roland company is the world's first UV inkjet printer using safe low heat LED lamps. It can not only print five colors of yellow, magenta, black and white and polish oil, but also has outstanding printing quality. The machine is mainly suitable for one-time packaging printing and short label printing, and can perfectly display a very rich special effect, whether it is the highlight effect or the texture effect can be presented one by one, and even reproduce the texture difference between artificial leather and crocodile skin

in addition, UV technology is also popular in the printing of self-adhesive labels. At present, UV glazing technology has been widely used in the label industry to replace the surface coating. The glazing of self-adhesive labels is carried out on the rotary label machine, that is, a layer of UV glazing oil is evenly coated on the surface of the text immediately after printing. For flexographic prints using water-based ink, glazing process is an essential process. Compared with traditional drying equipment, on equipment without UV drying, using ordinary ink needs to be bronzed before printing, and the disadvantage is that the design of printing pattern is limited. On the equipment with UV drying device, it can be printed first and then bronzed. After the ink dries quickly, it can be bronzed on the ink. The bronzing pattern is designed arbitrarily, which is not limited by the ink, and is suitable for the printing of high-grade labels

5 summary

in a word, UV technology does not need heat source and belongs to pure UV cold curing, which is suitable for the production of heat sensitive labels; And it can cure quickly (the curing time can be less than 1 second), and high productivity and high process output can reduce the storage of raw materials and finished products; UV technology the whole curing system is a solvent-free system, with 100% solvent-free formula, which is suitable for the production of special labels, and there are no VOC volatile organic substances, and it fully meets the requirements of environmental pollution regulations. It is believed that in the near future, technology will become the first choice for more and more label manufacturers

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