Application of Vacuum Aluminized Paper Printing and Its Ink (I)

Abstract: This article starts with the characteristics and process design points of vacuum aluminum-plated paper, and focuses on the application of various printing methods to substrate adaptability.

Keywords: vacuum aluminum coated paper, adhesion fastness, burst, ink slice

Aluminizing materials For the marking of cigarettes, it has both the metallic luster of composite foil jams and PET-coated cardboard, and the plasticity of white cardboard. Composite aluminum foil paperboard, also known as 裱 aluminum paperboard, is a direct use of aluminum foil and paperboard composite; PET coated paperboard, is the use of aluminum foil and cardboard composite.

First, the characteristics of vacuum aluminum paperboard

Vacuum aluminum-plated paper, or aluminum-sprayed paper, aluminized paper, and vapor-deposited paper, is a new type of green packaging material that has been applied more and more widely in the packing industry since the 1980s. Some experts predict that at the beginning of the 21st century, vacuum aluminum spray paper will become the darling of China's packaging industry.

The reason why it is called green material is that it adopts the method of vacuum aluminum plating. It only covers a layer of 0.25-0.3 micron (μm) thin and tightly shining aluminum layer on the surface of the cardboard, which is only a composite cardboard aluminum foil layer. One percent. As a result, it has both a metallic feel and a biodegradable, recyclable environmental property.

Vacuum aluminum-plated paper according to its production process can be divided into direct evaporation and transfer evaporation method. The direct method, also called paper surface aluminum plating, is to place the paper directly on the vacuum aluminum plating machine for aluminum plating. This method is limited to the aluminum spraying of thin paper, and the loose structure of the aluminized layer and the paper surface fibers are kissed and the surface will be presented. Fine holes, the smoothness is also relatively poor. Transfer method, that is, film surface aluminum plating, is to place the PET film in the vacuum aluminum plating machine after aluminizing, and then compound the glue with the paper, and then strip the PET film, and the aluminized layer is transferred to the paper jam surface through the adhesive effect. Made from.

Compared with the direct method, the advantages of the transfer method are: it can produce paper or paperboard of any thickness; fully utilizes the flatness of the PET film to make the paper metal luster brighter; it can produce rainbow holographic laser anti-counterfeiting and other arbitrary pattern texts as required. Aluminum paper products.

Second, the aluminum plating paperboard process design points

Vacuum aluminum-plated prints have poor wear resistance, low gloss, easy-to-break material, and easy-to-dark white crease lines. This can directly lead to bad markings, poor material stiffness, and poor printing inks. crack.

For this reason, in addition to selecting strong material suppliers, in the section of process design, try to avoid weaknesses by following the characteristics of aluminum-plated paper.

1, pattern text to avoid the use of a large area of ​​opaque ink for the background color, more exposed with the bottom effect, highlighting the unique metallic luster aluminum paper color.

2. When offset dot images are used, the area is preferably small, avoiding large-area four-color overprinting, and spot color printing is used to increase color saturation.

3. Select the color as much as possible to highlight the metal color and the gloss of the aluminized paper, and use less special spot colors. Choosing inks should also be printed with as good transparency as possible.

4. Pay attention to the effect of the metallic luster of the aluminized paper on the ink color effect. Different paper jam backgrounds will have different color effects. If printed on the aluminum layer transparent yellow, golden yellow.

5, small text and lines to avoid overprinting, so as not to reveal the bottom or color, increase overprinting difficulties, increase scrap rate.

6, try not to print a large-area spot color block at the crease line to prevent dew or crease lines, to make up for the lack of material folding.

In short, know more about the printing performance of aluminum-plated paper, the requirements of post-printing processing technology and the customer's packaging process on the machine, fully consider the printing particularity of aluminum-plated paper, and use the extreme colors together, starting from the actual situation is the eternal truth.

Third, the application of aluminum paper ink

1. Offset screen printing

The aluminum layer ink of vacuum aluminum-plated paper has poor ink adsorption, especially when the offset printing is performed, the process of ink penetration, polymerization, oxidation, conjunctiva, and drying on the vacuum aluminum-plated paper is longer. Due to poor adhesion, sometimes the ink breaks at the folds. UV offset printing inks can be tested for POP inks, and the viscosity of the inks should also be noted.

Offset and screen printing should be based on the ink drying speed to determine the boot speed, offset water control can not prevail dirty version. Many vacuum aluminum coated paper manufacturers often back coat water for the purpose of facilitating final drying, but do not perform backwater treatment before providing them to the printing company, making the aluminum coated paper easy to curl during the printing process. The surface of the aluminized paper itself has a certain amount of fine holes, and water can penetrate into the paper, which shows the importance of water control.

For the fastness of the ink, there are mainly two cases. First, the printed ink after the printing pulls off the ink to be printed first; second, the firmness of the ink layer on the surface of the paper after printing is not easy to pull off. For the solution, the former suggests increasing the UV curing intensity between the color groups or using a wet and wet overprint to complete the curing process at the delivery site at one time; the latter uses a high-toughness UV curing ink and adds a special varnish to the ink. Adjust its viscosity.

For the problem of color explosion, the general solution is: First, before the UV printing, water-based light oil rendering; Second, the use of special color blocks to increase the thickness of the ink layer twice to increase the folding endurance; Third, try to choose high toughness Ink.

2, gravure

From the adaptability of aluminized paper and gravure printing, today's requirements for ink are mainly focused on solving the problem of ink adhesion and burst color.

To achieve good adhesion between the aluminized paper and the gravure ink, the medium between the two, varnish is the key, it can not erode the plating layer, but also have a good affinity, but also does not affect the follow-up The leveling of printing. Insiders pointed out that the use of 300-mesh anilox roll in the aluminized paper, and then coated with a uniform water-based varnish, so that the paper surface tension increased to 38 dyne or more, can achieve the desired effect, the initial solution to the problem of gravure ink adhesion.

Once the aluminized paper is not properly controlled, it is easy to explode, which is related to the paper itself, PET film, glue, glue, ink, temperature control operation and other factors. In the case of inks, the ink binder consists of a resin and a solvent. The resin has the ability to contain and release pigments, and the solvent acts to disperse and dissolve. Different resin and solvent types and different deuterium ratios can determine ink transferability, drying properties, ink layer fastness and other performance indicators. General gravure inks are composed of two or three kinds of resins and two or three kinds of corresponding additives with pigments and mixed solvents.

According to the characteristics of aluminized paper, increase the proportion of flexible resin in the ink and the corresponding solvent, and the high degree of fineness of the pigment particles to adjust the standard, from the original 20-25 microns to 3-6 microns, if the choice of pigment color ink , can perform a quick sanding process on the color paste to refine the soft particles that are difficult to filter in the original color paste and optimize the processing without changing the characteristics of high transparency and high gloss. effect.

In addition, it is necessary to properly adjust the viscosity of the ink, improve the binding force and anti-explosion ability of the resin and the pigment.

The hue, saturation, and transparency of the ink are particularly important for the coloring effect of the aluminized paper. Normally, the fineness of the pigment sanding is achieved three to four times, but it is easy to darken the color of the paint. Thickness appears. To solve this problem, there are also important tips. The use of pigment color chips such as Zhuhai Fangdia Ink Co., Ltd., also called ink slicing, pre-dispersed pigments can bring the color of the pigment itself to its peak state due to its special production process. The translucent effect is also a powerful weapon that guarantees metallic luster on pure aluminum foil and aluminized paper products. It does not affect the unique effects of the aluminized laser paper, but also makes the ink transfer smoothly to meet the needs of overprinting, stacking flexibility, abrasion resistance, heat resistance, resistance to post-processing operations.