Due to the obvious advantages of the overall light effect and anti-counterfeiting performance of the hologram film, the hologram film has become a standard packaging in the fields of tobacco and alcohol, cosmetics, high-grade food and so on. In the hologram film packaging market, processes and materials have also been introduced, such as coating hologram film process, hologram transfer printing to hologram positioning printing and other developments, the material has also changed from plate seam hologram film to plate seam hologram film. Although the process and materials are constantly updated, the hologram film is still inseparable from the following processes in the production process: hologram molding plate, hologram printing, coating, slitting, transfer, aging and other processes. After finishing the film, several key steps are highlighted.
Hologram molding plate
It is one of the core links in the production of hologram film, the casting level of the plate determines the production quality of the hologram film, the casting hologram molding plate is completely different from the plate making in the printing process, the requirements are different, the hologram molding plate is made of special metal sheet by special electroforming, the plate material has strong hardness and flexibility, and can not be deformed under high temperature baking. And under the magnifying glass can not see any small defects in the layout. Therefore, the casting quality requirements of the hologram molding plate are very demanding. Plate material is also very expensive, so the use of very careful, in the erase plate, maintenance can not have any small collision, there can be no oil, water splash on the hologram molded plate, responsible will lead to product scrap.
Coating technology
Generally there are two kinds of hologram film materials, the distribution is BOPP and BOPET. BOPP can directly press hologram graphics on it, and BOPET is not, if you want to press hologram graphics on the BOPET base film, you must first apply a very thin special coating on the PET base film, and then press hologram graphics. In the process of coating special coatings, it is necessary to ensure the appropriate viscosity, and at the same time, there are high requirements for the coating environment, such as sealing, dust-free, constant temperature, constant humidity and so on.
Press hologram graphics
The principle of hologram printing is that the hologram die plate is directly pressed on the film substrate or special paint at high temperature to form uneven and varying light refraction points. After illumination, the diffuse reflection of different wavelengths of light will make the hologram film show rainbow light.
When pressing hologram graphics, it is necessary to master the three elements of temperature, speed and tension, if the control of these three elements is not accurate enough, it will produce serious color difference, black spots, white spots, water patterns, folds, clouds, pitting and other problems, and sometimes there will be hologram graphics and light column deformation and tension instability and other quality defects. These defects will bring great trouble to the post-printing, and even make the hologram film unable to be put into printing production.
Vacuum spraying
After the hologram image is finished, if the metal effect is to be achieved, it is necessary to spray a layer of metal foil on the hologram image. The vacuum aluminum plating machine is mainly used to atomize different metal wires through a strong current in a vacuum container and cover the hologram film. Plating process can be aluminum plating, chromium plating, nickel plating, copper plating, iron plating, can be plated matte plain surface, bright mirror and other effects, vacuum spraying effect depends on the metal material used.
Vacuum spraying process operation is very difficult, taking vacuum aluminum plating as an example, affected by voltage, current, vacuum degree, material purity and other factors, aluminum plating process may cause aluminum discoloration. Quality defects such as splashing, dropping aluminum, black spots, spots, and bubbles will affect the quality of the final hologram film, which is easy to cause poor transfer and a large number of aluminum drops.
After the vacuum spraying process, in order to ensure the smooth post-processing, the surface treatment of the metal foil must be carried out to improve the printability. There are two main treatment methods: coating varnish (paint) and corona treatment, which can be selected according to the different surface properties of the metal foil.
In addition to the above ordinary hologram pressing film technology, hologram holographic anti-counterfeiting positioning hologram molding technology is also a relatively new high-tech pressing film technology, different from the ordinary hologram film production process, when pressing the positioning hologram film, it is necessary to calculate the position of the holographic anti-counterfeiting hologram printing before plate making, implant the anti-counterfeiting pattern into the specific position of the hologram stamping plate, and then carry out hologram positioning molding. In this way, when the hologram holographic positioning hologram film is transferred, the anti-counterfeiting hologram pattern can be transferred to the same position on the printed surface.
