With the improvement of people's brand awareness, beer manufacturers increasingly focus on the image of beer packaging, not only on the body standard, but also in the beer bottle cap seal cap and so on. The material of the beer cap and the body mark is different. The body mark is generally printed on synthetic paper, and the cap label is printed using pure aluminum foil. Therefore, the cap label has a much higher requirement on the printing process and post-press processing than the body mark. In addition, for beer manufacturers, in addition to requiring a beautiful cap, but also requires easy labeling operation, and to achieve water resistance, antifreeze and other requirements. To meet the requirements of both beer manufacturers and printing manufacturers, the choice of gravure printing ink for beer caps is crucial. Here is a simple analysis of how to choose beer cap gravure printing inks.

Basic ink performance requirements and test methods

1. Printing ink adhesion fastness requirements If the ink adhesion is not fast enough, the printing plant may fade after printing, cutting and labeling at the brewery. Therefore, the adhesion fastness is an index that should be considered first when selecting an ink. The method for detecting the adhesion fastness is usually after the printing of the ink on the aluminum foil substrate, sticking with a tape, if it does not fade, it is qualified, otherwise it is unqualified.

2. The glossiness and vividness of printing inks Although the aluminum foil itself has a metallic mirror effect, if the ink with good gloss and vividness can be used, the printed pattern will be more vivid and more beautiful. As beer manufacturers, they certainly hope that their packaging will give people a sense of luxury, so the ink has enough gloss and vividness is of utmost importance.

3. The smoothness of the printing ink requires that if the label is not smooth enough, labeling will reduce the work efficiency due to sticking together, but it should not be too slippery; otherwise, the knife edge slippage will occur during the cut after printing, and even appear. The phenomenon that the production date and lot number cannot be printed. Therefore, the smoothness of printing ink should be appropriate.

The usual method for checking the smoothness is to place two 20cm×20cm unembossed prints with full-printed ink on each other, align them face-to-face, and fix one of them at 30° angle and 45° angle respectively. Test: At a 30° angle, if the print slides down, it indicates that the degree of smoothness of the ink is too high; at a 45° angle, if the print does not slide down, it indicates that the smoothness of the ink is insufficient. That is, it is required that the print cannot slide down at an angle of 30°, but it can slide down at an angle of 45°.

4. The water resistance and anti-freeze requirements of printing inks In summer, people usually drink beer after chilling and feel refreshed. Therefore, printing inks are required to be resistant to water and do not fade at low temperatures. The usual detection method is to freeze the prints in the freezer for 8 hours or soak them in ice water for 8 hours. Rub them by hand. If they do not fade, they are acceptable products.

Ink selection and use

1. The choice of beer cap gravure printing ink

Beer cap standard gravure printing ink, according to the characteristics can be divided into light oil, transparent ink, translucent ink. It depends on the packaging requirements.

(1) If the printed part is required to have the light reflection effect of the metal surface, the transparent ink should be used, but this type of ink is more expensive.
(2) If the prints are required to have bright colors, semi-transparent inks are generally available; if you want to get more vivid colors, you can first print a layer of varnish or white ink on the aluminum foil substrate and then print the translucent ink. Use a layer of varnish after printing the translucent ink. In contrast, the former will get more vivid colors.
(3) Some labels have only a small part of the pattern. Most of them are bare aluminum foils. At this time, a layer of varnish must be printed, otherwise the labels will be fragile and will not be easily cut.

2. The use of beer cap gravure printing ink

After selecting the desired ink type, the following methods are usually used for printing.

(1) Control of ink printing viscosity

The control of printing viscosity of ink is usually adjusted according to the printing speed of the printing machine. The speed is fast, and the viscosity is lowered. When the speed is slow, the viscosity is increased. The following principle is generally followed (viscosity test conditions: using a 3# test cup test at room temperature 25°C).
1 When the printing speed is 30~80 meters/minute, the ink viscosity is controlled at 16~22s.
2 When the printing speed is 80~120 meters/minute, the ink viscosity is controlled at 12~16s.
3 When the printing speed is 120~150 m/min, the ink viscosity is controlled at 9~12s.
It is worth noting that, in the printing process, to control the range of printing ink viscosity, it is necessary to add the solvent to the ink from time to time.

(2) Preparation of dilution solvent

Diluted solvents are classified into three types: quick-drying, medium-drying, and slow-drying, depending on the rate of volatilization.
1 For benzene-soluble inks, the usual diluent solvent is as follows.
Fast drying type: Toluene.. Isopropyl drunk.. Ethyl acetate=5..3..2.
In the dry type: Toluene.. Isopropanol: Butyl acetate = 6..3..1.
Slow-drying type: xylene: n-butanol: butyl acetate = 5:3..2.
2 For alcohol-soluble inks, the usual diluent solvent is as follows.
Fast drying type: Ethanol: Ethyl acetate=5..5.
In the dry type: isopropanol: butyl acetate = 6..4.
Slow-drying type: n-butanol: butyl acetate = 5:5.

Dilution solvents are usually selected according to the printing speed. Fast-drying diluents are used for fast printing, and slow-drying diluents are used for slow printing speeds. Diluted with the required resin precipitation, thereby destroying the ink, which is the basis for ensuring the printing effect.

(3) Control of ink color

Aluminum foil substrate is different from other materials. As long as the color of the ink is slightly different, the color difference printed on the aluminum foil substrate will be very obvious, so the control of the color concentration is very critical. When reducing the color density during the printing process, dilution solvents should not be used blindly. They should be used with diluting agents because the dilution solvent will significantly reduce the viscosity of the ink, while the diluting agent will only dilute the ink and will not reduce the ink. Viscosity. Therefore, the adjustment of the color density is usually a combination of diluting agent and diluent solvent. For spot color inks, it is advisable to use spot colors prepared by ink manufacturers, which can reduce ink color differences.

In addition, printing manufacturers should accumulate their own printing experience data, adjust their own printing technology parameters according to different printing conditions, in order to ensure that the best printing effect can be achieved.