Hot stamping refers to the process of hot stamping electrochemical aluminum foil onto the surface of the substrate under a certain temperature and pressure. The images and texts printed by hot stamping of electrochemical aluminum present a strong metallic luster, with bright colors and never fade. In particular, gold and silver hot stamping embellishes the surface of printed materials with its magnificent, exquisite and elegant decoration, enhances the artistry of printed materials, and plays a propaganda effect of highlighting the theme; its brightness greatly exceeds that of gold and silver printing, making the product feel high-end and giving people a beautiful enjoyment. At the same time, because hot stamping aluminum has excellent physical and chemical properties and plays a role in protecting printed products, hot stamping technology is widely used in high-end and exquisite packaging decoration trademarks, calendars and book covers and other printed materials; secondly, hot stamping of electrochemical aluminum has a very wide range, from general book covers, trademark patterns, publicity advertisements, plastic products to daily necessities, from paper to leather, cotton cloth, etc.; thirdly, hot stamping is a dry processing method, and the workpiece can be immediately packaged and transported after hot stamping. Therefore, hot stamping technology is widely used, and the scope of hot stamping is still expanding.
Hot stamping process
Since the quality, specifications, and models of electrochemical aluminum foil will affect the quality of hot stamping, the scientific and reasonable selection of electrochemical aluminum foil is a prerequisite for improving the quality of hot stamping process.
Process flow
Hot stamping preparation → plate mounting → plate padding → determination of hot stamping process parameters → trial hot stamping → sample signing → formal hot stamping.
Hot stamping principle
The process mainly uses the principle of hot pressure transfer. Under the action of combined pressure, the electrochemical aluminum contacts the hot stamping plate and the substrate. Due to the heating of the electric heating plate, the hot stamping plate has a certain amount of heat. The electrochemical aluminum is heated to melt the hot-melt dyeing resin layer and adhesive, and the adhesion of the dyeing resin layer decreases. The viscosity of the special heat-sensitive adhesive increases after melting. The aluminum layer is peeled off from the electrochemical aluminum base film and transferred to the substrate. As the pressure is removed, the adhesive quickly cools and solidifies, and the aluminum layer is firmly attached to the substrate to complete a hot stamping process.
From the composition and hot stamping mechanism of electroplated aluminum, in order to obtain the ideal hot stamping effect, the electroplated aluminum foil used for hot stamping must meet the following requirements: the bottom layer is evenly coated, without obvious color difference, color stripes and color spots; the base glue coating is even, smooth, white and free of impurities, without obvious stripes, sand spots and oxidation; good gloss; strong firmness; high clarity; correct model.
Determining factors
The perfect hot stamping effect mainly depends on the level of mutual coordination between temperature, pressure and hot stamping speed. Therefore, to control the quality of hot stamping, the reasonable hot stamping temperature, hot stamping pressure and hot stamping speed should be mastered. In this way, good conditions are created for hot stamping, and the quality of hot stamping can be guaranteed in the end.
Folding temperature
Temperature has a very important influence on hot stamping. The temperature must be controlled within the corresponding range to melt the dyeing resin layer and adhesive moderately to ensure the good transfer of the aluminum layer.
If the temperature is too high and the melting is excessive, the electroplated aluminum around the hot stamping image will also melt and fall off, resulting in a paste plate. At the same time, the high temperature will also cause chemical changes in the electroplated aluminum dyeing resin and the aluminum layer, reducing the brightness of the hot stamping product and losing its metallic luster, and even causing the imprint to appear foggy or bubbling; but if the temperature is too low and the melting is insufficient, it will also cause the hot stamping to fail or not be strong, the imprint is not strong, easy to fall off, or the pen is missing and the imprint is flowery.
Folding environment
The machine should be installed in a dry, ventilated, well-lit place that is convenient for operation.
Folding pressure
The hot stamping transfer of the aluminum layer must be completed by pressure, and the size of the hot stamping pressure affects the adhesion of the electroplated aluminum. Even if the temperature is appropriate, if the pressure is insufficient, the electroplated aluminum cannot be transferred well to the substrate, which will cause problems such as weak imprints and flowery plates; on the contrary, if the pressure is too high, the compression deformation of the pad and the substrate is too large, and the imprint will be coarse, or even sticky and paste the plate. Usually, the hot stamping pressure should be appropriately reduced to achieve the principle of no fading and good adhesion.
Adjusting the hot stamping pressure requires a combination of factors such as the substrate, hot stamping temperature, vehicle speed, and the electroplated aluminum itself. Generally speaking, when the paper is strong and smooth, the printed ink layer is thick, and the hot stamping temperature is high and the vehicle speed is slow, the hot stamping pressure should be smaller, otherwise it should be larger. The hot stamping pressure must be uniform. If it is found that the hot stamping is not done or there are spots in some parts, it is likely that the pressure here is too small. A layer of thin paper should be placed on the flat plate at that place to balance the pressure. The hot stamping pad also has a great influence on the pressure. The hard pad can make the print beautiful and is suitable for strong and smooth paper, such as coated paper and glass cardboard; while the soft pad is the opposite, the print is rough and is suitable for hot stamping of a large area, especially for uneven surfaces, poor flatness and smoothness, and rougher paper. At the same time, the installation of the hot stamping foil should not be too tight or too loose. If it is too tight, the handwriting will be missing and broken; if it is too loose, the handwriting will be unclear and the plate will be smudged.
Folding speed
The hot stamping speed actually reflects the contact time between the substrate and the hot stamping foil during hot stamping, which directly affects the fastness of hot stamping. If the hot stamping speed is too fast, it will cause the hot stamping to fail or the imprint to be blurred; if the hot stamping speed is too slow, it will affect both the hot stamping quality and the production efficiency. Speed, pressure, and temperature restrict each other during the hot stamping process, and its process parameters are always determined in the order of hot stamping speed, pressure, and temperature. First determine the hot stamping speed. In general, it is treated as a constant and not easily changed, and then the hot stamping pressure and hot stamping temperature that are suitable for it are found, which can simplify the operation procedure and make it easier to control the hot stamping quality. In addition, during the hot stamping process, it is also necessary to consider whether the substrate, hot stamping plate, hot stamping machine, fixture, and pad are suitable. Finally, the environmental conditions should be studied, including indoor temperature and humidity, substrate temperature, and indoor air cleanliness (dust content). In short, the hot stamping process is a complex process technology. Only by grasping the above issues during the hot stamping process can a satisfactory hot stamping effect be obtained.
Precautions
1. Small hot stamping machines must select suitable hot stamping foils according to the different types of objects to be stamped. When hot stamping, the temperature, pressure and hot stamping speed must be coordinated well, and they vary according to the hot stamping materials and hot stamping areas.
2. The speed and direction of the lathe tool should be mastered when cutting.
3. The electrochemical aluminum hot stamping foil should use paper, ink (especially black ink), kerosene, and composite glue with suitable properties. The hot stamping parts must be kept dry to avoid oxidation or damage to the hot stamping layer.
4. The general packaging is: 64CM×120M per roll, 10 rolls per box; the width can be customized to 64CM, the length is 120M or 360m large rolls or other special specifications.
5. When storing, it should be placed upright, pressure-proof, moisture-proof, heat-proof, and sun-proof, and placed in a cool and ventilated place
Post time: Jun-01-2024