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High-grade packaging on the three-dimensional hot process requirements
- May 11, 2018 -

In recent years, with the improvement of the appearance and quality requirements of products, printing technology and packaging technology have made great progress, and post-press processing technology has achieved vigorous development, while hot stamping of aluminum foil has been used as post-press processing. As part of this, the changes in recent years have been even greater. The continuous emergence of new technologies, new processes and the combination of multiple technologies has enabled the printed products to achieve good results in terms of glossiness, three-dimensionality, metallic sensation, and anti-counterfeiting performance after hot stamping, especially for the current applications. A wide range of three-dimensional hot stamping technology makes the packaging of goods appear high-end fine, magnificent and full of personality. At present, the technology is mainly used for greeting cards, bookmarks, trademarks, tobacco and wine packaging and various high-grade packaging boxes.

Three-dimensional hot stamping process requirements:

(1) Electrochemical aluminum foil

Electrochemical aluminum foil generally consists of 4 to 5 layers of different materials, such as: base film layer (polyester film), peeling layer, colored layer (silvered aluminum without color layer), aluminized layer, adhesive layer.

The main role of each layer is:

1 The base film layer mainly serves to support other layers.

2 The role of the peeling layer is to separate the electro-aluminum foil layer from the base layer, which determines the transferability of the electro-aluminum layer.

3 The main role of the color layer is to display the color of the aluminum and protect the underlying layer. The common colors are gold, silver, brownish red, light blue, black, red, green, among which gold and silver are the two most commonly used.

4 The role of the aluminized layer is to show metallic luster.

5 The function of the adhesive layer is to act as a bonding hot stamping material.

The adhesive materials that make up the adhesive layer differ in their adhesive properties. In order to adapt to the different surface properties of different stamping materials, different bonding layers are used for the electroformed aluminum, thus constituting different types of electro-aluminum.

Hot stamping speed and quality are mainly affected by the peeling layer and the adhesive layer. If these coatings are not sensitive to heat, the hot stamping speed will be reduced accordingly. In the past, due to the limitation of heat transfer speed, the flat stamping and hot stamping speeds were low, reaching less than 5,000 sheets per hour. However, some of the world’s leading suppliers of anodized aluminum have produced enough aluminum products to meet the industry’s demand for hot stamping. Printing speed requirements

(2) Temperature, pressure, speed

Temperature, pressure and speed are the three major elements of hot stamping technology. Only by controlling the relationship between the three can control the quality of hot stamping. The same applies to three-dimensional stamping. Since the three-dimensional bronzing is a complete bronzing and embossing stamping, the temperature requirements are even higher. The normal bronzing temperature is only 70°C to 90°C, while the three-dimensional bronzing can be completed at about 150°C. If the temperature is too low, the adhesive layer and the peeling layer of the galvanized aluminum may not be fully melted, and the galvanized aluminum foil may not be completely transferred during hot stamping, resulting in that the hot stamp is not on the exposed or exposed bottom. If the temperature is too high, the paper will be deformed too much, the image will be confusing, the writing will be unclear, and even the phenomenon of anodized aluminum will change. At the same time, the hot stamping plate may swell too much due to the high temperature, and it may not be accurate. Mold fit, resulting in bad hot stamping. Therefore, the temperature control is the first of three major factors.