Application of the hottest UV curing in flexograph

2022-08-08
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Application of UV curing in flexographic printing III

III. curing process of UV coating

UV coating is initiated by photoinitiators after UV radiation to produce free radicals or ions, which cross-linked with the double bonds in oligomer unsaturated monomers to form monomer genes, thereby initiating polymerization, cross-linking and grafting reactions, so that the resin < UV coating, ink Adhesives, etc.> change from liquid to solid in a few seconds (this change process is called "UV curing"), and the complete curing process ended a day ago

uv flexo printing ink has excellent physical and chemical properties. The process of UV curing and drying is the photochemical reaction of UV ink, that is, from linear structure to shape structure, so it has many excellent physical and chemical properties, such as water resistance, alcohol resistance, wear resistance, aging resistance, which are inferior to other types of ink. UV flexographic ink has good printing applicability, high printing quality, no change in physical properties in the printing process, no volatile solvent, stable viscosity, not easy to paste and stack plates, strong inking force, high dot definition, good tone reproducibility, bright ink color, firm adhesion, suitable for fine product printing

at present, there is still a process for the promotion and application of UV printing technology in China. On the one hand, it is a further understanding of UV flexo printing technology; On the other hand, the equipment, light source, supporting equipment and process technology should be improved and perfected together. This requires the cooperation of equipment manufacturers, ink companies and light source companies to achieve perfect printing curing effect. For example, UV light source: UV flexo printing implements peak staggering production in industrial enterprises, and each color group needs to be equipped with UV light source. UV flexo printing inks of different colors have different abilities to absorb UV rays. For example, yellow and magenta have strong absorption abilities, which are easier to cure and dry, while blue and black have weak absorption abilities of UV rays, which are harder to dry, which are cured at the back and the power is increased. The power of UV lamp can be allocated according to different colors, so as to ensure the reasonable drying of UV inks of various colors, and at the same time, it can also save the source of what can be expected. Pay attention to the aging of UV lamp, and replace the UV lamp in time to prevent incomplete curing and adhesion

the service life of UV lamp is 1000 hours, and frequent startup will significantly shorten the service life of lamp

IV. suggestions on the application of UV curing device in flexographic printing

1 The complete UV curing device shall be divided into three parts: light box, power control and cooling device

2. The appearance of the lamp tube should be small and complete, and ensure that the cooling air can flow smoothly

3. The power of the light source is high, and the power can be converted into full power, half power or 75% power

4. The fan is controlled by the electrical box, and there should be 6 ~ 8 minutes of delayed air cooling after turning off the light to cool the lamp

5. The main switches are equipped with indicator lights, and the main electrical components are protected

6. Quartz heat insulation sheet can be installed on the lamp tube for curing of thermal sensitive materials

at present, the number of flexo printing machines and rotary machines equipped with UV ink curing systems in foreign countries is increasing, and the existing labeling machines are also constantly refitting UV ink curing systems. It has become a development trend to replace water-based ink and solvent based ink with UV ink, which has been widely used in soft concave machines. Undoubtedly, the development prospect of UV flexo printing technology is very good. The promotion and application of domestic UV flexo printing technology needs to be based on our national conditions and product needs, and also needs to be matched and improved by domestic equipment manufacturers to improve the cost performance of products and the stability and durability of equipment. With the increasingly stringent requirements of environmental protection and quality, but the workbench is relatively large, it is believed that in the near future, the domestic UV device technology will also have a greater development

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