Application of UV screen printing ink in the most

Application of UV printing ink in self-adhesive label printing

UV printing has environmental protection, high-speed printing and excellent printing effect, and is gradually recognized by the majority of printing manufacturers. Therefore, in recent years, the application of UV ink has also developed rapidly in the field of self-adhesive labels. This paper focuses on the application of uv-pvc printing ink in the field of self-adhesive printing. I would like to discuss with colleagues in this paper

traditional self-adhesive labels are mostly printed with solvent based ink. Due to factors such as low printing efficiency, color difference and relatively unstable quality, it is difficult to undertake label orders with large quantities, fast delivery time and high requirements. The above problems can be well solved through the cooperation of full-automatic multi chromatic high-speed printing machine and UV printing ink. At present, the full-automatic label printing machine produced in Taiwan, China and Japan has a printing efficiency of more than 3600 times per minute, and the average printing time of a single label is 0.8 ~ 1 s. Because UV printing ink is used for printing, the printed labels are incomparable to traditional solvent based inks in terms of color, brightness and fullness of ink layer. According to incomplete statistics, at present, there are more than 60 such production lines in China, and a number of label orders of well-known brands in China have been printed to improve the quality and quantity. The application of UV printing ink in self-adhesive label printing is briefly introduced below

1. printing materials coated paper adhesive, PVC adhesive, treated polyester adhesive

2. Silk s-grade mesh/cm (mesh/inch) silk

3. scraper hardness, polyurethane rubber scraper

4. uv-pvc inks produced by shitiao in Japan, Dolby in France and Henderson ink coatings (Hangzhou) Co., Ltd. can be used

5. printing precautions

(1) the ink should be fully stirred before printing

(2) the viscosity of UV ink is closely related to the ambient temperature of printing. When the temperature is low in winter, the viscosity will become higher, and when the temperature is high in summer, the viscosity will become lower. Generally (℃), the ink can be directly printed after being opened and stirred. However, when the temperature is low (ink viscosity increases) or high-speed printing, 5%-8% UV diluent should be added and diluted before printing. The higher the printing speed, the lower the ink viscosity should be adjusted. However, it should be noted that if the UV diluent is added too much, it is easy to reduce the adhesion and curing of the ink

(3) when printing, the angle between the scraper and the plate should be adjusted to.. The angle is too small, which is easy to cause ink seepage; If the angle is too large, it is easy to cause too little ink and affect the printing quality

(4) when printing, the distance between the plate and the printing material should be adjusted to 3 ~ 5 mm. If the distance is too low, it may affect the springback speed of the version; If the pitch is too high, it will affect the leveling of the ink, causing the smoothness of the ink layer to decrease

(5) it is worth noting that when printing ~iln-, attention should be paid to the superposition of the back color and the front color. If the UV curing of the front color is too complete, it is easy to cause poor adhesion when printing the back color overlay. Therefore, when multi-color printing is required, the U V light intensity of the front color printing must be reduced. Generally speaking, when the curing degree of the front color ink is 60%-70%, the back color is superimposed, so the RTI certification of domestic modified high molecular is still in the low stage, and the printing will not have adhesion problems. When the curing degree of the front color is 90% - 100%, it is easy to cause poor adhesion of the back color printing. It can be solved by turning off some UV tubes or improving the printing progress

(6) generally speaking, uv-pvc inks have excellent physical and chemical resistance, but some labels, such as those used outdoors, should choose inks with excellent weather resistance. It should be noted that after the color ink is printed, a protective varnish is covered and printed, which can greatly improve the outdoor weather resistance

reprinted from: printing technology

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