Author: Wang Shouhong Various technologies are emerging in the printing industry, one of the fastest growing is energy curing technology. It means that the ink or glazing paint is fixed or hardened on the substrate under the irradiation of radiant energy, thereby obtaining a dry imprint. UV light and accelerated high-energy electron beam (EB) are two energy forms of energy curing technology. Accordingly, inks cured with UV light and EB energy are called UV inks and EB inks, respectively. Due to the good drying effect and low pollution, the cost of use has also been significantly reduced in recent years, so it is more and more favored by printing manufacturers. This article will focus on some related issues about EB curing inks. The curing principle of EB ink The drying of the ink film layer of ordinary ink after printing is that the connecting material (solvent, grease) in the ink is absorbed and volatilized by the substrate, and the solid substances (colorant, resin, wax, desiccant, etc.) remain on the substrate surface to form A thin layer of ink. The difference between the drying of general ink and the fixation of energy curing ink is that the chemical composition of the ink / glazing coating is different, and the second is whether the printing workshop needs to be equipped with energy curing equipment. EB ink and ordinary ink drying principle process EB curing is a form of radiation curing. It is a process that uses an electron beam as a radiation source to induce a specially formulated 100% reactive liquid to quickly transform into a solid. The principle is: first, high-energy electrons interact with the paint or ink molecules to decompose them into free radicals; then, the free radicals react with the C = C double bond to form a growth chain; and finally, the growth chain interacts with the rest of the paint or ink The components react to crosslink the cured coating and increase the crosslink density. Due to the high energy of the irradiated electrons, the above reactions are often accompanied by negative reactions such as molecular degradation and molecular ion rearrangement. As a result, the EB cured coating produces a greater degree of branching and a higher crosslink density. EB curing requires special curing equipment. Its working principle is: after the electrons are emitted from a group of linear cathode plates, they are accelerated by a vertical uniform electric field, and a curtain-shaped electron beam is obtained under the accelerator irradiation box. Because the irradiated product is closer to the electric field, its acceleration voltage is not high (less than 500kV), but due to the large output current, the power is higher. The linear cathode gun is far more compact than the scanning device, it is easier to install on the production line and easier to shield. Features of EB curing technology As a new type of curing technology, EB curing has unique advantages compared with traditional curing technology. The curing time of the first EB ink is very short, generally only 1/10 second can be completely dried and fixed on the surface of the substrate. For traditional thermosetting inks and sheet-fed offset inks, the drying time may take a few minutes or even a few It takes only days to dry completely. Therefore, energy-curable inks are used to print offset printing jobs. The delivery time is short, which is comparable to flexo and gravure printing, and greatly improves the productivity of offset printing. The EB energy range required for the second curing is 150 to 300 keV. It reaches the surface of the cured material at a rate close to the speed of light. Not only is it not limited by the color of the coating, but it can also cure the adhesive between the paint inside the paper or other substrate and the opaque substrate (such as aluminum foil). The third EB curing can make coatings, inks and adhesives 100% curing, especially for areas where the curing degree must be 100%, such as food packaging. Thirdly, the printed matter printed with energy curing ink has strong resistance. Because the chemical substances in the ink form a polymer three-dimensional network polymer through the cross-linking reaction, the surface of the ink has strong chemical resistance and friction resistance. The solid content of the fourth EB ink after curing is close to 100%, and usually does not contain VOC (organic volatiles), which strongly shows that the EB ink system is more environmentally friendly than the ordinary ink system. For example, the chemical composition of EB ink is properly prepared, and the odor is much smaller than that of ordinary ink with many oxidized conjunctivas, and the surface of the printed product is clean and free of dirt. Fifth, with the development of technology, the irritating effect of EB curing ink on human skin is getting smaller and smaller, which is similar to that of ordinary ink containing gasoline fraction. The sixth energy consumption is low, the energy consumption of EB curing is 5% of UV curing, and 1% of traditional thermal curing. Easy to operate, easy to control, high accuracy and repeatability, no environmental pollution. The development of EB curing technology and its application in printing At present, EB curing technology is mainly used in flexographic printing, offset printing and glazing in printing. EB ink is a special ink cured with electron beam energy. Printers using EB inks require special rollers, fountain solutions and cleaning agents, because the surface energy of the EB gondola is different from traditional inks. In the early 1970s, the American Ford Xia Company applied EB curing technology to auto parts and instrument coatings for the first time, which created a precedent for the application of EB curing technology in industrial production. During the same period, Album Printing Company used EB curing inks and coatings on packaging materials. Early EB curing technology was limited to the printing or glazing of web materials. This is because on a sheet-fed printing press, the gripper row will interfere with the X-ray shielding generated by the electron beam device. On the web printing machine, the EB curing device is located at the end of the printing machine, and it is easily fixed above the web material without support. Through continuous efforts of the R & D personnel, this problem has now been solved. EB curing technology has been widely used in the field of sheet paper folding carton, sheet paper commercial printing and so on. Today, high-quality EB curing technology has become the best choice for flexible printing. This is not only because it meets the requirements of environmental protection, but also because of its excellent printing quality and the declining price of EB curing equipment (EB curing equipment has dropped from more than 1 million US dollars to 200,000 US dollars today, There is a further downward trend). The biggest breakthrough of EB ink application is its application in CI (Central Impression Cylinder) label flexo printing machine. In the printing process, the ink achieves wet-wet overprinting without the need to dry after each color is printed. With EB technology, only one EB curing system can be used to instantly and completely dry the substrate, that is, a "dryer" replaces multiple sets of drying devices in traditional printing. In label printing, EB glazing has also been widely used. The main difference between EB varnish and EB ink is that the former contains no pigment. In UV glazing, in order to obtain good gloss, it is often necessary to perform double-layer coating. The first glazing coating unit applies a water-based primer to the substrate. This coating isolates the offset ink and UV varnish to prevent chemical reactions, and simultaneously prints the graphic and non-graphic parts The microscopic unevenness is filled; the second glazing unit is coated with UV varnish to make the printed products get better printing effect. Up to 3 hot air blowers need to be equipped in between to achieve complete drying of the printed matter. EB curing has the outstanding advantage of being able to cure thicker films. EB glazing replaces traditional double-layer to multi-layer structures with "single-layer" films, which greatly saves materials and greatly reduces production costs. According to statistics, only the process of glazing and coating can reduce the production cost by about 10% by using EB glazing. In this field, the most effective progress is the successful development of Sun Bean with low solubility. It is allowed to come in direct contact with food and can be used as an internal coating for food packaging. Today, the product has been widely used, such as coating inside film packaging, multi-layer cloth bags, food boxes, etc. When applying EB glazing, it is necessary to pay attention to the compatibility with ordinary printing inks, because the wax and lubricant in ordinary inks will hinder the wetting of EB varnish. By using EB curing, the coating layer that originally required a few minutes or even a few days to be completely dried can be dried in an instant, realizing a streamlining operation and greatly improving production efficiency. The application of EB curing technology greatly shortens the time from printing, storage, glazing to packaging and transportation, so that the entire process of printing, glazing, packaging and transportation can be completed in one day, which truly meets the high efficiency of today Sex and requirements. The application prospect of EB curing technology in printing field EB ink (varnish) has many advantages, making EB curing technology show strong vitality in the future development. (1) It does not contain VOC, no odor or only a small odor, which reduces the harm to workers' health and no environmental pollution. (2) Good resistance, because the chemical substances in the ink form a polymer three-dimensional network polymer through the cross-linking reaction, the ink film has good chemical resistance and friction resistance. (3) The curing time is short, generally only 0.1 seconds can be completely dried, compared with the traditional printing takes a few minutes or even a few days to completely dry, which greatly improves production efficiency and is conducive to large-scale production. (4) The pigment has a high concentration background, the printed product has a beautiful appearance, and has a strong gloss and a three-dimensional sense. (5) Reduce the cleaning time of the printing machine. Even if the EB ink in the ink fountain is stored overnight, there will be no skinning and hardening, which reduces waste. (6) During curing, there will be no strong heat that causes the substrate to deform. Of course, as a new type of curing technology in development, EB curing technology also has some shortcomings. For example, in recent years, although the price of EB curing equipment has been greatly reduced, its one-time investment is still large; the price of EB ink is still higher than the price of ordinary ink; EB curing is only suitable for the curing of flat coatings. Therefore, the geometry of the cured product is limited; an important characteristic of EB ink is that it has good resistance, but this becomes a factor that makes it difficult to deink and hinder the recycling when recycling waste prints. Therefore, in the aspect of print recovery New research must be done. In short, the application prospects of EB curing technology in the packaging and printing industry are promising. In order to make the EB curing process more convenient and economical, we should actively develop low-cost, compact EB curing equipment, improve the transmission device, so that the product can be rotated and cured, so that radiation curing can be applied to products of various shapes. It can be asserted that EB curing technology will have greater development in the future due to its characteristics of low pollution, low energy consumption and high quality. Workout Bike,Upright Exercise Bike,Cross Trainer Bike,Best Exercise Bike Zhejiang Kingdom Sports Co.,Ltd. , https://www.zjkingdomsports.com