UV glazing materials and process indicators (5)

5 Oxygen less cure faster

Oxygen has a strong absorption of ultraviolet rays, and nitrogen filling the coating surface will accelerate the curing speed.

The selection of the specific curing time is related to the following aspects:

According to the characteristics of the coating machine, such as screen printing machine, the printing speed is about 600 to 2000 pieces/hour, and the uv gloss oil is coated with a 350 mesh screen, and the power density of 80W/cm lamp can meet the requirement. Four-color offset press printing uv offset printing ink, with three power density 80w/cm lamp, printing speed of 7000 / h. Flexo printing machine, gravure printing machine coating uv light oil, the number of lines is 165 lines anilox roller, with a 120w/cm lamp tube, curing speed of 80w/min. Generally choose to cure faster than the coating speed.

According to the print material temperature resistance. The non-temperature resistant material has a faster curing speed so as to avoid deformation of the material, such as a plastic film, and the coating is cured just after the surface is exposed to light, but the temperature does not reach below and the light is left, so that the material base layer is not deformed. White paper is easy to dehydrate, and it also needs to be cured quickly.

Eight, uv coating oil viscosity adjustment

The uv gloss oil content is generally required to be between 92% and 98%, with few solvents. From the formula to solve the problem of improper viscosity, the high viscosity is easy to achieve, only adding tackifiers, on the contrary is more difficult. The viscosity can also be adjusted by changing the ambient temperature. Generally, the roller and the storage tank are heated to 55 degrees to reduce the viscosity. Another method is to add a diluent, but this approach is not ideal, the thinner hinders the curing, affects the brightness of the film, and the intermediate does not participate in the curing, and is ultimately wasted causing environmental pollution.

Nine, the general uv coating thickness:

Film thickness is related to the following aspects:

1. It is related to the gloss and density of the paper surface. Paper bright, high density, non-permeability need thinner film thickness instead.

2. It is related to the customer's requirements. If you only need to cover the ink, you must be thin. If you want a three-dimensional effect, you need to be thicker.

3. With the polishing machine. It cannot be too thick with an offset press or a convex printer, because the pressure is large, and coating with a three-roller coating machine is not possible because the pressure is small, and the coating can be quantitatively adjusted with a gravure printer or a flexo printer. .

4. It depends on the running speed of the coating machine. Such as flexo, gravure printing machine when the speed is high, oil thin, anilox roller mesh high coating film is thin. If a low mesh is used, the viscous oil cures without leveling and the glazing layer is spot-like and not a film.

Adjust the film thickness according to the above factors. General copper paper surface ink is 1 ~ 4g / square meter, film thickness 1 ~ 4 microns; white version of paper surface with ink 3 ~ 12g / square meter, thickness 3 ~ 12 microns.

Ten, uv polishing of fuel consumption

The amount of uv light oil can be determined based on the following factors:

1. Polishing machine structure. For example, the most simple three-roller coating machine, because the roller pressure is small, no uniform ink roller, so the coating amount of varnish is relatively large, and often the coating amount far exceeds the required amount, and the general coating amount is more than 6g/m2. The use of anilox roller coating, the coating amount of 2g/m2 or less. The amount of enamel coating machine coating 2 ~ 8g/m2. The amount of coating on the screen machine can hit 50g/m2. General local three-dimensional art glazing, glazing film thickness of about 0.5mm, three-dimensional touch by hand. Glue and convex printing machine coating gloss 1 ~ 3g/m2.

2. Paper surface brightness. UV glazing should be said to be the icing on the cake, but it is only applicable to paper with high surface brightness or materials with poor surface absorbability to varnish. If the surface of the material is rough, immediately after the varnish is applied, it will seep into the lower layer, and a bright film will not be formed on the surface, so there is no sense of glossing. The material on the paper surface is only coated paper and white paper can be coated with uv oil. The copper card (glass card) has a very good effect with an oil content of 2 to 3 g/m2. In general, coated paper is coated with about 3 to 5 g/m2 of oil, and white paper is coated with about 5 to 12 g/m2 of oil. (Finish)