The hot stamping process is to use the principle of hot press transfer to transfer the aluminum layer in the anodized aluminum to the surface of the substrate to form a special metal effect, because the main material used in hot stamping is anodized aluminum foil, so hot stamping is also called anodized aluminum hot stamping.
(1) Process introduction
Anodized aluminum foil is usually composed of multiple layers of material, with the substrate often PE, followed by a separating coating, a color coating, a metallic coating (aluminized), and a glue coating.
In the printing industry, it is commonly used to stamp anodized aluminum foil on paper, which is called hot stamping, which is a general term for a process. Hot stamping does not mean that it is golden. There are many kinds of hot stamping paper materials, including gold, silver, laser gold, laser silver, black, red, green and so on.
(2) Process application
1. Ordinary gold and laser gold hot stamping. It can be used for most products, including gold cards, silver cards, laser cards and hot stamping on glass cards, and its application is more common.
2 Positioning holographic bronzing. Holographic laser positioning anodized aluminum is a special process application in design, with corresponding anti-counterfeiting patterns, which can greatly improve the anti-counterfeiting ability of the product, and at the same time improve the grade of the product. This kind of anodized aluminum is generally produced domestically, and compared with foreign imports, it is cheaper, but the hot stamping performance is slightly worse. Holographic laser positioning anodized aluminum has a great relationship with the control of hot stamping temperature, hot stamping pressure and vehicle speed, and even hot stamping models.
3 Special application of anodized aluminum in the process. Ironing before printing is a new idea in the cigarette label design and printing industry. The application of the process has high requirements for anodized aluminum, in addition to achieving the requirements of accurate hot stamping position, smooth and bright surface, pressure balance, uniformity, no blistering, no pasting, etc., special attention should be paid to the edge of the hot stamping pattern can not have obvious indentation, and the hot stamping anodized aluminum should have good adhesion on the hot stamping surface, as well as no obvious scratches and scratches. As we all know, the bronzing process is actually a process in which the paper is heated and pressurized. For white cards and glass cards, special attention should be paid to the protection of semi-finished products, and various unfavorable factors of paper deformation should be minimized in the production process, so as to greatly help the smooth progress of the hot stamping process and the improvement of product qualification rate.
(3) Types of fabric bronzing processes
Cloth bronzing technology has developed rapidly in China, but it has been put into mass production since 2000. With the rapid development of science and technology, the fabric bronzing process is becoming more and more mature, because the overall effect of the cloth after its bronzing appears graceful and trendy, has won more and more beauty lovers love.
With the continuous development and updating of bronzing technology, cloth bronzing has a subdivision of the industry, taking bronzing equipment and bronzing methods as an example, there are generally two kinds of common bronzing equipment:
1) Round pressing round cloth bronzing:
The hot stamping plate and the bottom die punch are both cylindrical, and there is a linear contact between the two cylindrical rollers, and the bottom die punch is generally made of silicone material with moderate hardness. This hot stamping machine is suitable for making a whole roll of narrow roll cloth strip bronzing. The benefits: high speed and high yield. The bronzing paper used, under normal circumstances, in addition to the metal coating on the back, also comes with a bronzing adhesive, as long as the gold foil paper is selected properly, and the performance of the hot stamping machine is accurately debugged, and the fastness of the cloth strip after the bronzing is basically OK.
But this thing, there is also a shortcoming, because the cloth more or less has some tension, in the process of doing the whole roll of cloth strip bronzing process, the cloth strip and the bronzing paper are moving at the same time, when doing multi-color bronzing, it is not easy to control the accuracy of the color register, at this time, you can only retreat to the second, first do a good job of monochrome bronzing, do better.
2) Flat flat cloth bronzing:
The more common hot stamping machine is: pneumatic hot stamping machine or manual hot stamping machine, the main components are composed of two metal plates. When making fabric bronzing, generally, the aluminum plate above is heated and moves downward. The pressure and time that need to be considered when bronzing depends on the height of the glue layer of the printed pattern and the temperature that the fabric can withstand. In most cases, the temperature is between 140° and 160°, the pressure is more than 5kg, and the time is 10 seconds (reference value). The temperature is too low, and the gold fastness is not ideal;On the contrary, after the cloth is bronzing, the cloth surface is reddish (or white cloth is yellow) and discolored. If the pressure is too low, the fastness will be affected;If it is too high, the pattern of the three-dimensional bronzing paste will collapse and lose its three-dimensional effect.
When using this method to make fabric bronzing, there is a premise: add bronzing glue with the screen plate, print the pattern you need on the surface of the fabric in advance, and then enter the hot stamping machine to do fabric hot stamping after it is completely dry. After the bronzing is done, it is set aside to cool completely, and the waste gold foil is torn off to inspect and repair the packaging, and the entire fabric bronzing process is completed.