Application of UV Ink in Self-adhesive Label Printing

Traditional screen printed adhesive labels are mostly printed with solvent inks. Due to factors such as low printing efficiency, color difference, and relatively unstable quality, it is difficult to undertake large-scale, fast delivery, and high-demand label orders. . With the cooperation of fully automatic multi-color high-speed screen printers and UV screen printing inks, the above problems can be well solved. At present, China's Taiwan and Japan-made automatic label screen printing press, the printing efficiency per minute more than 3,600 prints, the average time of single label printing in the 0.8 ~ 1 S. Due to the use of UV screen printing inks for printing, the printed labels are incomparable to traditional solvent inks regardless of color, brightness, or ink layer fullness. According to incomplete statistics, there are currently more than 60 such production lines in China, and they have printed orders for a number of well-known brands in China. The following is a brief introduction to the application of UV screen printing ink in stickers printing.

1. Printing materials coated paper stickers, PVC stickers, polyester adhesive processing.

2. Screen S-150-165 mesh/cm (380-420 mesh/inch) screen.

3. Squeegee hardness 70-75, polyurethane squeegee.

4. Ink can be selected from Japan, France, Dolby, and Henderson ink coating (Hangzhou) Co., Ltd. and other production of UV-PVC ink.

5. Printing notes

(1) Stir the ink thoroughly before printing.

(2) The viscosity of UV ink is related to the ambient temperature of printing. When the winter temperature is low, the viscosity becomes higher, and when the summer temperature is higher, the viscosity becomes lower. Under normal circumstances (20-30 °C), the ink can be directly printed after being jarred. However, when the temperature is low (ink viscosity increased) or high speed printing, should be added 5% -8% of UV thinner, dilute and print. The higher the printing speed, the lower the ink viscosity should be adjusted. However, it should be noted that if an excessive amount of UV diluent is added, the adhesion and curability of the ink may be easily reduced.

(3) When printing, the angle between the blade and the screen should be adjusted to 70-80. . If the angle is too small, it may cause bleeding. If the angle is too large, the amount of ink may be too small to affect the printing quality.

(4) When printing, the distance between the screen and the printing material should be adjusted to 3 to 5 mm. If the net distance is too low, it may affect the rebound speed of the screen; if the net distance is too high, the leveling property of the ink will be affected and the smoothness of the ink layer will be reduced.

(5) It is worth noting that when there are multiple sets of color printing ~IlN-, attention should be paid to the problem of the superposition of the back color and the front color. When the current color of UV is cured too much, it is likely to cause poor adhesion when the back color is overlaid. Therefore, when multiple color printing is required, the UV light intensity during the preceding color printing must be reduced. In general, when the pre-color ink is cured at 60%-70%, there is no problem of adhesion when printing after-color printing. However, when the current color curing degree is 90% to 100%, the situation that the adhesion of the post-color printing is likely to be unfavorable. This can be solved by turning off part of the UV lamp or increasing the print schedule.

(6) In general, UV-PVC inks are excellent in both physical and chemical resistance. However, if certain labels are applied outdoors, they should be selected for their excellent weather resistance. It should be noted that after the color ink is printed, overprinting the layer to protect the varnish can greatly improve the outdoor weatherability.

Reprinted from screen printing