In recent years, with the improvement of appearance design and quality requirements of product packaging, printing technology and packaging technology have made great progress, and the post-press processing technology has achieved a booming development. However, As part of the process, the changes in these years are even greater. New technology, new technology and the combination of a variety of technologies continue to emerge, so that the packaging and printing by stamping in the gloss, three-dimensional, metallic, security performance have achieved good results, especially the current application of more and more A wide range of three-dimensional hot stamping technology, so that the packaging of goods look beautiful, magnificent and full of personality. At present, the technology is mainly used for greeting cards, bookmarks, trademarks, tobacco and alcohol packaging and a variety of high-end packaging.
Stereo gold stamping process requirements:
(1) electrochemical foil
Aluminum foil generally consists of 4 to 5 layers of different materials, such as: base film (polyester film), peel layer, the coloring layer (silver aluminum oxide without coloring layer), aluminum, adhesive layer.
The main roles of all levels are:
1. basement layer mainly from the role of supporting other layers.
2. The role of the peel layer is to separate the aluminum foil layer from the base layer, which determines the transfer of the aluminum layer.
3. The main role of the coloring layer is to display the color of aluminum and the protection of the underlying. Common colors are: gold, silver, reddish brown, light blue, black, red, green, etc., of which gold and silver are the two most commonly used.
4. aluminum layer is the role of metal luster.
5. role of adhesive layer is played from the role of hot stamping materials.
Adhesive layer composed of different adhesive materials, its adhesive is also different. In order to adapt to the different surface properties of different hot stamping materials, the aluminum foil will adopt different adhesive layers to form different types of aluminum.
The speed and quality of the stamping are mainly affected by the peel-off and adhesive layers. If these coatings are not sensitive to heat, the speed of the stamping will be reduced accordingly. Previously, due to the heat transfer rate constraints, the lower flat-speed stamping, are less than 5000 / hour, but at present some of the world's leading supplier of aluminum to make its production of aluminum is sufficient to meet the industry's hot India speed requirements, the Swiss Bobst hot stamping machine has achieved a speed of 7500 copies / hour. As a result of three-dimensional bronzing embossing pattern, temperature, speed and pressure control and ordinary bronzing are different, so the requirements of hot stamping foil and general bronzing are also different, the choice of hot stamping foil should use three-dimensional bronzing dedicated Hot stamping foil, but can not be used as ordinary hot stamping foil three-dimensional bronzing, or stamping will produce poor quality or other unexpected phenomena.
(2) temperature, pressure, speed
Temperature, pressure and speed hot stamping technology is the three major elements, and only control the relationship between the three in order to control the quality of hot stamping, three-dimensional bronzing the same. Because the three-dimensional bronzing is a complete bronzing and embossing, the temperature requirements are higher, the ordinary bronzing temperature as long as 70 ℃ ~ 90 ℃, while the three-dimensional bronzing is about 150 ℃ to complete. If the temperature is too low, it may appear that the aluminum oxide adhesive layer and the peel layer can not be sufficiently melted, and the aluminum foil can not be completely transferred when the temperature is too high, resulting in no hot stamping or a bare bottom. The temperature is too high, there will be excessive deformation of the paper, paste and paste, and illegible, and even the phenomenon of discoloration of aluminum, but also may be due to excessive temperature so that the hot plate too much, but not accurate and the end Die with, resulting in poor printing phenomenon. Therefore, the temperature control is the first of three major elements.
Hot stamping pressure refers to the moment of hot stamping version of the surface pressure. In the hot stamping process, the fused aluminum oxide adhesive layer is pressed to complete the transfer of aluminum, so the pressure of the size and uniformity of a direct impact on the quality of hot stamping. In addition to the three-dimensional gold foil transfer to the surface of the printed aluminum foil, but also with a huge pressure in the hot stamping parts of the three-dimensional relief pattern, so the pressure is greater than ordinary bronzing, which also requires the strength of hot foil to be better, To be able to withstand strong pressure squeeze. Of course, this does not mean that the greater the pressure, the better, must be appropriate, too much pressure can not get exquisite designs. Excessive pressure may crush hot foil, or even crush the bottom mold and to be hot printed products; and the pressure is too small, it may produce incomplete transfer of hot foil or hot stamping, embossed three-dimensional embossed reach Quality requirements. So stress control is equally crucial.
Hot stamping speed is actually hot stamping contact with the time of the aluminum, aluminum that is the heating time. Hot stamping speed, short heating time, hot stamping temperature decreased rapidly, causing the temperature is too low, hot stamping fastness will be affected; hot stamping slow, long heating time, hot stamping temperature slow down, hot stamping fastness, However, if the control is not good, it will cause the stamping temperature is too high fault. Therefore, the appropriate speed of hot stamping is also a guarantee of high quality stamping effect.
Stamping and embossed stamping technology are traditional post-press processing technology, packaging and decoration is an indispensable process, and now combined with the use of the two, not only reduces the production process and improve production efficiency in the quality of the product packaging, Decoration effects and security features have been greatly improved. So this technology now shows a strong momentum of development, with all aspects of maturity, it will gradually replace the original stamping and embossing two processes to form a three-dimensional gold pattern process. Three-dimensional gilding process will be printed in the field of packaging and decoration is very promising decorating techniques.