Process characteristics of aluminum foil offset printing

Aluminum foil printing is a special printing process in packaging and decorating printing. It has the same features as general paper printing, but also has its differences. Because the surface of the aluminum foil is aluminum metal, it has flashes that are not possible with ordinary paper, and it also has a certain effect of isolating air, moisture, heat insulation, and corrosion resistance. After being compounded with polyethylene, polypropylene and other films, aluminum foil has become a new type of material for packaging and decorating products, and its use has become wider and wider, especially in the production of alcohol, cosmetics and other packaging.

In recent years, more and more printing methods using aluminum foil offset printing technology. Among them, most use offset printing UV printing. However, offset UV printing requires dedicated UV offset presses, UV inks, blankets, etc. In addition, special UV lamps are also required, which consumes a lot of power, and therefore have a high cost. Therefore, the use of ordinary offset printing presses and ordinary ink to print aluminum foil has become a topic that we must solve.

The aluminum foil paper has a good visual effect against the background of metallic luster, plus fine network lines, rich colors and color blocks, and its packaging and decorating products are favored. However, since the surface of the aluminum foil is relatively smooth, ink absorption is poor, and therefore, it is necessary to solve the problem of dryness of the ink and the fastness of the print. The aluminum foil paper adopts ordinary offset printing methods and general ink printing methods. It has passed numerous trials and achieved good results in our company, which has been recognized and welcomed by users. In order to ensure the printing effect, the following points must be noted:

1. Understand the properties and characteristics of aluminum foil.

At present, aluminum foil on the market generally has two kinds of rolls and flat sheets. According to the production method, its types include:

Vacuum aluminum spray paper—spray aluminum on paper to create a metallic feel. The smoothness and gloss of the paper are inferior to those of other aluminum foils, but the ink absorption during printing is better and the drying speed is also faster.

Aluminum paper jam—0.006-0.016mm thick aluminum foil and cardboard composite paper. The surface has a strong metallic feel and a higher gloss than aluminum spray paper, but the ink absorption and drying properties of the print are inferior to those of the sprayed aluminum paper.

PET coated aluminum paper - PET film by vacuum aluminum and paper composite paper. The metal feel is particularly strong and the gloss is high, but the printing ink absorption is relatively poor and the drying speed is slow.

Aluminum foil is generally 99.9% pure aluminum, after high-temperature melting, rolling into 0.006-0.016mm thin slices, can also be made into very fine powder particles spray coating. After the above methods and the combination of bottom paper, made of aluminum foil. However, the bottom sheet must be of good quality and smooth surface, otherwise it will affect the flatness and gloss of aluminum foil. The aluminum foil itself is silver, but it can be dyed and colored to meet the needs of various hue packaging and decorating products. Aluminum foil is generally made of high-gloss glare, can also be made of low gloss matte, according to the needs of packaging products and use.

2. According to the characteristics of aluminum foil packaging and decorating design and plate making.

For foil foil offset printing to achieve good results, the characteristics of the foil itself must be taken into account in the design and plate making, and the sparkling metallic brilliance should be revealed as much as possible. The design of the design should not choose a large block, strong hiding power; design should use good transparency ink printing, such as aluminum foil printed with transparent yellow can be turned into gold, in order to take full advantage of the aluminum foil's own luster, make it bright Metallic glory. According to the design pattern, it is also possible to combine certain special printing processes such as embossing and embossing, hot stamping, and the like so as to make the aluminum foil print more artistic. This artistic effect is unmatched by other papers. In addition, the plate-making should fully consider the effect of printing, generally should not stack too much ink, especially in the field full version of the larger block surface, aluminum foil printing is much more difficult than ordinary paper, in the dark part of the pattern is easy to stick dirty And scratch, can use non-color structure of the plate method.

3. Grasp the process of offset printing.

1 aluminum foil offset printing must use high-quality ink, requiring high ink color, good transferability, fast drying and good print fastness. It is best to use special inks, such as Shanghai-made POP inks.

2 Strictly control the acidity value of the fountain solution and the moisture of the printing plate layout. The fountain solution plays an important role in the drying of aluminum foil offset printing. Therefore, the pH and conductivity of the fountain solution must be strictly controlled during printing. To make measurements, speak with the data and keep the plate layout water to a minimum. This minimizes the emulsification value of the ink.

3 ink layer should be uniform, the amount of ink should not be too large to avoid sticking and scratching. In the preparation of spot color inks, dark color printing should be used.

4 The speed should not be too fast and should be maintained at an appropriate speed.

5 printing products should not be stacked too high, piles of paper is too easy to cause the back of the printed product is dirty. In the printing can be the right amount of powder or infrared drying.

6 Strictly control printing pressure, the pressure of imported multi-color offset press is generally controlled at 0.08-0.10mm