How to use waterproof varnish in cartons

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How to use carton waterproof varnish

1, light source: UV irradiation light source generally adopts high-pressure mercury lamp or metal halide lamp (electrodeless lamp is preferred), and the power of light source also requires stability. The output power of high-pressure mercury lamp is generally 80 ~ 120w/cm to ensure that the curing speed of the coating is less than 0.5s

2, paper coating is not suitable for processing paper that is easy to penetrate, because the low molecular materials in the coating are easy to penetrate into the paper, causing the paper to darken or even soak. In this case, Only accelerate ink "> printing speed, and increase the number of light tubes. In order to prevent penetration, you can first coat the bottom layer with an infrared base to avoid penetration when coating.

3, ink: you need to pay attention to the combination of paint and ink, and apply a layer of primer first if necessary.

4, coating thickness: after the polishing coating is irradiated by ultraviolet light, the photoinitiator is triggered, which will produce free radicals or ions, which will interact with the prepolymer Or the double bonds in unsaturated monomers react to form monomer groups. These monomer groups will generate polymer solid polymers through chain reaction, and complete the drying of glazing coatings. Our footprint process is also spread at home and abroad. The use of new materials in the coating layer is an inevitable trend of development. Under the irradiation of the same power light source, the drying time is relatively long, which will affect the drying of the glazing oil on the one hand, and reduce the water content of the paper on the other hand, which will make the paper brittle and fragile, and affect the wear resistance of the oil layer

5, diluent: Generally speaking, special diluent is required for glazing oil, and the dilution amount is controlled at about 1:0.5 to 1:1. Too much will affect the glazing effect (depending on the amount of film)

6, poor gloss: if the paper quality is poor or the surface is rough, and the oil absorption is large, you should use a higher level of paper; If the coating is uneven or the polish is diluted too thin and the viscosity is too low, the polish machine should be adjusted and the viscosity of the Polish should be increased; Poor adhesion, crystallization of printing ink layer or improper use of ink additives and antiskid agents should improve the printing process, and no or less ink additives should be used; The viscosity of glazing oil is too low, so it should be adjusted to ensure the correct online glazing machine and improve the viscosity of glazing oil

7, the glazing layer is white: the crosslinking density is low. Diluent is not used properly. Because alcohol solvent volatilizes quickly in summer, diluent should be replaced or ester diluent should be used

8, the coating layer is yellowish: the polish coating is too thick, and the viscosity is only 0.93 g/cubic centimeter, so the viscosity should be reduced; When the Polish expires (the service life is generally 6 months), it should be stopped

9, adhesion (not fully dried): if the coating is too thick, the viscosity should be reduced; If the lamp power is insufficient or aging, replace the UV lamp to reach the rated power

10, poor smoothness: the coating roller of the glazing machine is damaged or the viscosity of the glazing oil is high. Replace or regrind the roller to reduce the viscosity of the glazing oil

11, safe production: some imported polish is irritant to the skin. In addition, it is non-volatile. When it is attached to the skin and clothes, it may enter the skin with sweat and cause inflammation if it is hot in summer. Therefore, if the skin is stained with Polish during the production process, it should be cleaned with soap and water as soon as possible and clothes should be changed in time. In addition, attention should also be paid to the temperature and humidity control of the environment and the hot stamping property of paper prints after UV varnishing

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