Holographic transfer film production and processing technology

The so-called holographic transfer technology refers to the use of the peelability of chemical coatings, the aluminum layer with a rainbow holographic effect deposited on the film and molded into the surface of the paper, the formation of metallized holographic paper production technology. Because holographic transfer products have rainbow interference stripes, high metallic luster, and are biodegradable and easy to handle, they can meet the requirements of green environmental protection, and thus become newer and alternative products for hot foil and film products, and have broad market prospects. In recent years, the domestic holographic transfer material technology has been continuously developed and the transfer project has been launched. However, due to the corresponding defects in the performance of holographic transfer products, there are still some concerns in the use of major smokers, so no large-scale use of holographic transfer has been formed. The situation of packaging products. Of course, manufacturers of holographic transfer films are constantly researching and improving the performance of their products, and strive to achieve user-friendly green packaging effects as soon as possible.

Regardless of the production process, product performance and use, the holographic transfer process and chemical coating components are the key technologies for holographic transfer production. The maturity of the process technology, the use of raw and auxiliary materials, etc., are slightly inappropriate. The surface of the printed product will have poor adhesion of aluminum layers, cracks, burst color at die-cut creases, and poor ink adhesion. In October 2002, our company introduced an Italian CERUTTI 960 gravure printing machine, which can directly connect BOPP or PET transfer film and paper to compound, dry, peel, print and on-line UV varnish. The production process using traditional transfer paper for printing processing effectively avoids the above problems in the printing surface of the transfer packaging product, and can open the transverse layout seam (positioning printing) of the holographic transfer film.

Holographic Transfer Film Introduction

There are many kinds of holographic transfer films, and holographic transfer films with different prices and different types should be selected according to different product structures, peeling effects, drying effects, ventilation volume of drying channels, drying path length, and printing speed. Commonly used OPP, PET holographic transfer film structure shown in Figure 1, Figure 2, the base film performance shown in Table 1.

Holographic transfer film production and processing technology

Holographic transfer production and processing processes are numerous and the process is more complicated. The complete process flow is shown in Figure 3.

For most holographic transfer film manufacturers, the product is a substrate for printing. Processes to be completed include: dosing, coating, molding, aluminum plating, compounding, and stripping, slitting, and rewinding. The processes to be completed for the connection, compounding, transfer, and printing of an integrated device include: composite (holographic transfer film and paper), peeling (aluminum layer transfer is separated from the base film on the surface of the paper), varnish, and printing, eliminating the need for purchase. The process of transferring paper and then printing effectively reduces the cost of paper.

1. Batching process

The resin and the solvent are mixed and stirred according to the formula ratio, and then the corresponding amount of the dye is added according to the desired color for color toning, and finally a colored or colorless coating liquid (abbreviated as color paste) having a certain viscosity and solid content is formed. Coating.

2. Coating process

The coating solution was evenly coated on a PET or BOPP base film using a coating apparatus (coating machine) to form a uniform and dense coating layer for separating the aluminum layer from the base film at the time of peeling. In order to obtain a dense coating, it is necessary to control several process standards at the time of coating: 1 viscosity of the coating liquid; 2 dry coating amount; 3 coating effect; and 4 coating peelability. In addition, the coating speed should be adapted to the oven length of the coating equipment, the hot air temperature, and the coating solvent to ensure that the coating is fully leveled and that the solvent is volatilized as much as possible (to avoid residual odor).

3. Molding process

The formation of holographic transfer products is inseparable from the molding process. Molding is the process of embossing the embossed pattern on the nickel plate onto the coating or aluminum layer by using the thermal properties of the chemical coating, including hard pressure and soft pressure. In order to obtain a clear, bright holographic pattern, it is necessary to control the molding temperature, pressure, speed and other process parameters. Especially in the molding process, the indoor air must be ensured to be clean because the base film itself has strong electrostatic adsorption. If the base film adsorbs dust and then the mold is pressed, the surface of the holographic transfer film after aluminizing will remain. Rainbow highlights.

4. Aluminizing process

Using aluminizing equipment (aluminizing machine), a uniform layer of aluminum is sprayed on the surface of the molded layer to form a holographic glossy surface effect with a rainbow metal effect. The technical indicators that need to be controlled are: (1) The thickness of the aluminum layer should be guaranteed at 300-350 A; (2) The integrity of the aluminum layer can not be scratched, large bright holes, or missing plating.

5. Complex process

The process of bonding the holographic transfer film and the backing paper with an adhesive (water-based glue, environmental protection). Since paper can be breathable, a wet compounding method is generally used, that is, the glue is first applied, and then is pressed and then dried by a pressure roller. The type of adhesive used will affect the quality of the final product to a certain extent; the sizing method can use three-roll sizing, and can also use anilox roller sizing. In addition, the oven temperature and the mechanical operating speed determine the dry conditions of the product. The technical indicators that need to be controlled are: 1Comprehensive fastness; 2Surface flatness; 3 Peel integrity.

6. Stripping process

The base film is separated from the paper so that only the adhesive, aluminum layer and coating remain on the surface of the paper, but there is a gleaming metallic luster and the desired color and holographic pattern; the peeled-down PET or BOPP base film can be renewed The reuse of coating greatly reduces the production cost. The quality of the stripping process depends largely on the previous process such as coating preparation, coating, and compounding. The factors that need to be controlled during stripping are: 1) tightness of the winding, 2) regularity of winding, 3) surface abrasion, and 4) Recovery film recycling management.

Holographic Transfer Product Performance

Compared with foil-clad and film-covered products, the performance of holographic transfer products can meet or exceed the latter two. The following is a brief introduction.

1. The brightness of the product

Clad foil (general aluminum foil, no base film) is divided into two kinds: positive and negative. Film products are often used as bright products (base film on the surface). In holographic transfer products, the brightness of bright light transfer products cannot reach the brightness of bright aluminum plated composite products (a polyester paper jam), but the brightness of holographic composite products has been achieved; and the gloss and matt effect of the matt transfer products are similar. Al foil reversal products are basically the same.

2. Printability

As a printing substrate, good printability is particularly important. For holographic transfer paper, this performance depends to a large extent on the resin composition of the transfer coating. Good printability includes ink leveling effect and adhesion. At present, holographic transfer products can basically meet the requirements of printability.

3. Explosion phenomenon

After the holographic transfer product is printed, after the post-processing such as die-cutting indentation, for a period of time, the ink layer and the transfer layer at the indentation will have relatively slight cracks and can transmit light. This phenomenon is unique to transfer products. Composite products do not exhibit this phenomenon because the surface of the composite product has a base film. After die-cutting, the surface has very strong flexibility. There is a slight explosion of color in all the transferred products, but the flexibility of the pulp fiber of the bottom paper has a great influence on the degree of color burst.

4. High temperature resistance

Since the printing process is such as hot stamping, or in the OPP heat-sealing stage of cigarette packaging, high temperature is required, the surface resin of the product to be transferred can withstand high temperatures of 120 to 150° C., and can not discolor within 0.5 seconds. Hair flower, the current transfer of products can basically meet the requirements.

5. Folding resistance

After the holographic transfer paper is repeatedly folded several times, the transfer layer will not be damaged, which mainly depends on the film forming properties of the adhesive after drying. The current transfer of products can basically meet this requirement.

The exquisite and beautiful green packaging gives people the enjoyment of the United States. The development of society and the progress of mankind also have higher requirements for environmental protection. Green holographic transfer technology, combined with sophisticated advanced production processes, reflects the current market demand. To be in line with international standards and be responsible for the physical and mental health of mankind, we must start from now and shoulder this sacred mission of serving human health. To update products, introduce new technologies, and create miracles.

Reprinted from: Printing Technology