The market potential of radiation-curable inks

In recent years, with the continuous improvement of technology and the increase in market demand, radiation-curing inks have achieved rapid development in Europe. Especially in the packaging field, UV/EB printing inks, typical representatives of radiation curable inks, have been widely used. It has improved the quality of printed products and increased the popularity of commodity brands.

First, the UV/EB ink curing principle

The drying of the ink film after the printing of ordinary ink is that the binder (solvent, grease) in the ink is absorbed and volatilized by the substrate, and the solid material (coloring material, resin, wax, desiccant, etc.) remains on the surface of the substrate. A thin layer of ink. General ink drying and energy curing ink fixation, the difference lies in the ink / coating coating chemical composition is different, followed by whether the printing shop needs to be equipped with energy curing device device. Therefore, it is also called energy-curing ink because it contains some chemical substances that generate free radicals or ionic radicals under the action of UV light or high-energy electron beams, and radicals or ionic radicals are then cross-linked with other substances into a network-like polymer. .

The so-called UV / EB ink, is the use of UV curing or electron beam energy curing ink. Compared with traditional drying inks, it has some unique features: First, UV/EB inks have fast curing speed and high production efficiency. Generally, they can be completely dried and fixed on the surface of the substrate in 1/10 seconds. Second, After the UV ink is printed, the glossiness of the printed product is quite high, and the surface is even and uniform. Third, the printed material obtained by printing with radiation-curing ink has strong resistance; Fourth, UV/ EB inks do not contain organic volatiles (VOCs) and are more environmentally friendly. Fifth, energy-curable inks are less irritating to human skin and are beneficial to the health of workers. The curing process saves energy.

Despite this, UV/EB inks have yet to be widely used in printing. The biggest challenge comes from the technical aspects, including ink manufacturers, equipment manufacturers, and suppliers of chemical materials such as surface additives. development of. Specifically, the problems of UV inks are mainly manifested in issues such as odor, substrate adhesion, high-speed production, and the cost most considered by the printing service providers. In fact, these problems have been affecting the development of UV inks since they were first applied in the printing field in the 1970s, and they still plague the entire industry.

Of course, once the problem is solved, UV inks will replace water-based inks in certain areas and become the most environmentally friendly and durable ink. With the European Union's legislative restrictions on VOCs, the use of solvent-based inks has been restricted. Water-based inks have used this good opportunity to beat a considerable market and become the new darling of the printing industry. However, printers are increasingly dissatisfied with water-based inks because their quality has not yet reached their expectations. At the same time, suppliers in various fields, such as inks, equipment, and raw and auxiliary materials products, have been working together to solve problems related to UV/EB systems. Fortunately, some technologies have also been improved and developed to make radiation curing more efficient and less costly.

Second, the status of radiation curing ink

According to the data, at present, the percentage of radiation-cured inks in the total printing ink is less than 10%, which is mainly due to the difficulties in the promotion and application of offset printing and narrow-width rotary flexo printing. According to data analysis provided by Pira, a British packaging consulting company, in the area of ​​European packaging printing, UV/EB inks account for about 65% of the total offset ink sales, which is equivalent to about half of the total UV/EB ink sales in the entire packaging field.

For UV flexo inks, 80% to 90% are used for packaging printing, most of which are used for label printing. In the printing process of gravure printing, digital printing, and screen printing, the application of UV/EB ink is not satisfactory and the market share is relatively low. However, with the continuous breakthrough of new technologies, especially the improvement of ink adhesion, UV/EB inks have also begun to develop steadily in areas where the original amount was not so good.

In the improvement of ink adhesion, Eltex, a professional company dedicated to static control, has made great contributions. At present, they have successfully developed professional systems to offset the adverse effects of static electricity in print production. For example, by reducing the need for photoinitiators and reducing the inhibition of oxygen on the surface of printed substrates, the effectiveness of UV inks in sheet-fed and web offset press applications is increased and production costs are reduced. The greatest innovation of the Eltex system is that it requires less photoinitiator than many UV systems: its demand is only 1% to 3%, and some systems are up to 10%. It is reported that Eltex also applied innovative curing technology to the field of gravure printing. In this field, this new curing technology ensures that the UV coating of the magazine cover is completed on the gravure printing unit without the need to resort to an off-set thermosetting offset press. At the same time, the speed of UV coating can be coordinated with printing speeds of 420 meters/hour or 25,000 printing/hour.

Publication printing is a potential area of ​​development for radiation-curable inks, as the glazing production of magazines (especially covers) and booklets is a trend. In addition, the application of new curing technologies in packaging and other fields has also increased the ability of UV inks to withstand harsh environmental conditions. This has been welcomed and paid attention to in the field of gravure printing, especially in packaging gravure, UV ink has obtained further development and wider application. At present, many brand owners are recommending that the printing service provider use UV inks for packaging printing production to obtain a powerful visual impact effect, which in turn helps the brand's marketing and construction.

Third, the huge market potential of radiation curing ink

In recent years, the electronic industry and digital technology have developed rapidly, and the demand for radiation-cured materials has further expanded. At present, the use of UV/EB curing inks still has some limitations, mainly because the price is quite different from traditional inks. Therefore, the application of UV/EB printing ink is also mainly concentrated in high value-added production areas or high-efficiency application fields such as inkjet printing, flexo printing, and high-grade packaging printing.

In the field of digital printing, UV inks have only received limited development. Recently, the continuous development and improvement of technologies have made radiation-curable ink increasingly widely used in inkjet printing. The greatest advantage of UV inks in digital printing is that its stability is relatively good. It can only be dried and cured under the irradiation of UV light. This can effectively avoid jamming the print head and thus extend the actual life of the print head. But the downside is that many factors will lead to a decrease in the speed of printing, such as the limitations of the ink supply itself, and the speed at which a large amount of ink passes through the print head. In addition, the characteristics of digital printing itself have also somewhat delayed the development of radiation-curable inks in its field. The most prominent problem is that the composition of printer ink is limited by the printing equipment manufacturers, which greatly affects the customization of the customers. The supply and development of inks and other required inks.

In order to better meet market demands and promote the development of UV/EB inks in the field of digital printing, many well-known manufacturers have already developed new products as their important plans, and have launched corresponding innovative technologies and products. One of the world's largest manufacturers and suppliers of screen printing inks and prepress products, the United States's Sericol Corporation has introduced UV-curable ink Uvijet series for inkjet printing. This series of inks can be used for a variety of substrates, including paper and cardboard, as well as various polymers such as PVC, polycarbonate, polypropylene, and polyethylene.

In the field of screen printing, equipment suppliers have also developed special screen systems to make the use of UV inks more efficient. This ensures that UV inks can play an outstanding role in the reproduction of fine four-color images on CDs and DVD discs. . The technical improvement of UV screen printing inks for CD and DVD disc printing has effectively promoted its market share in screen printing inks. According to statistics, the proportion of UV screen printing inks has been higher than 25%, and its annual growth rate is as high as 5%-10%.

Fourth, there are still problems with radiation curing ink

At present, the biggest problem for radiation-cured inks is that the two requirements for high-speed printing and firm adhesion to the printed substrate cannot be solved at the same time. The preferred solution to overcome poor adhesion of UV products is to increase the viscosity of radiation-curable inks, but higher viscosity means lower printing speeds. An ink with a relatively high molecular weight does not easily shrink under irradiation with UV light, which is a major cause of poor adhesion, and it is also not easy to eliminate the odor. In fact, inks with higher molecular weights usually contain acrylic binders, have higher temperature resistance, and can effectively promote curing. In actual production, the ink suppliers have not actively tried to provide highly viscous inks because the printing service providers seeking high-speed printing have become accustomed to using low-viscosity inks.

At present, various excipients provided for improving the adhesion of UV/EB ink also have certain disadvantages. For example, some products contain certain solvents that do not normally work well with UV/EB inks. In addition, ink manufacturers cannot ask printers to invest in additional equipment to eliminate these solvents to meet the European Union's requirements for organic volatile compounds. Provisions.

In short; only better to solve the problem of adhesion, UV / EB ink can occupy a certain market in the printing ink. Compared to water-based inks, UV/EB inks have many obvious advantages, especially its high temperature resistance. We have reason to believe that the application of UV/EB inks will be more extensive once the adhesion is more effectively improved and resolved, especially in the laminated composite processing field.

Source of information: pack.cn