The Application of UV Screen Printing Ink Label Printing

1 printing material: coated paper stickers, PVC stickers, processed polyester stickers.

2. Mesh: S-class 150~165 mesh/cm (380~420 mesh/inch) screen.

3. Scraper: hardness 70 ~ 75, polyurethane squeegee.

4. Ink: UV-PVC inks available from Japan Ten, France Dolby, and Henderson Ink Coatings (Hangzhou) Co., Ltd. can be used.

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 mixing. However, when the temperature is low (ink viscosity increased) or high-speed printing, should be added 5% to 8% of UV thinner, dilute after printing. The higher the printing speed, the lower the ink viscosity should be. However, it should be noted that if an excessive amount of the UV diluent is added, the adhesion and curability of the ink may be easily reduced.

(3) When printing, the angle of the blade and the screen is adjusted to 70-80°. If the angle is too small, ink bleeding is likely to occur. If the angle is too large, the amount of ink is too small to affect the printing quality.

(4) When printing, the distance between screen plate and printing material should be adjusted to 3~5mm. If the network distance is too low, it may affect the co-elastic speed of the screen. If the network 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 multi-color printing, attention should be paid to the problem of the superposition of the back color and the front color. The current color UV curing is too thorough, it is easy to cause after the color overlay printing, the phenomenon of poor adhesion. 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% to 70%, there is no problem of adhesion when printing after-color printing. However, when the current color curing degree is 90% to 100%, it is likely to cause poor adhesion of the after-color printing. 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 some labels are used outdoors, they should be selected for their excellent weather resistance. It should be noted that after the color ink is printed, a layer of protective varnish is overprinted, which can greatly improve the outdoor weather resistance.

Source: Shenzhen Printing Network