How to improve the quality of hot stamping aluminum

Anodized aluminum stamping, also known as hot flashing aluminum and anodized aluminum printing, is one of the biggest features of a special printing process that does not require the use of a rubber roller for inking, and uses a vertical flattening printing press for hot stamping. Corrosion of the zinc plate and copper plates from the corrosion of the powder or engraving of the copper plates. Using a polyvinyl alcohol glue or other adhesives, the zinc plate and the copper plate (15 mm thick) are adhesively attached and fixed on the electric plate of the printing plate platform, and the temperature is controlled at 70-. Between 150°C, each time the stamping is performed, the tube of electro-aluminum is rotated by the gear control shaft roller to move a certain distance according to the length of the platen, leaving the unfinished electro-aluminum left for the next stamping. The color of the anodized aluminum is mainly gold. In addition, there are dozens of colors such as red, green, silver, prison, orange, navy blue, and so on. It is full of colorful, colorful, can be hot stamping all kinds of packaging and decoration, high standards, tobacco, wine decoration, books and magazine covers, calendars, toothbrushes, plastics, linoleum, paint paper, wood products, wooden chopsticks, wooden fans, crafts and so on.
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Electro-aluminum hot stamping is characterized by brilliant gold products and beautiful color. It plays a role in embellishing commodity packaging and decorating. It is favored by people. Rich and elegant decoration is irreplaceable by other printing methods, and it has low cost, wide application scope and simple procedures. . Electrochemical aluminum stamping must grasp the relationship between temperature, time, and pressure.
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I. Composition, quality, and storage of electrochemical aluminum

Electrochemical aluminum foil is generally composed of five layers of different materials.

 The first layer is the base film layer, which mainly plays the role of connection and support. It is composed of nylon filament film of 0012~0020mm thickness. 

The second layer is a shedding layer that acts as a barrier. Its main component is a hot-melt silicone resin that melts and falls off on heating. 

The third layer is a colored layer, which determines the color of the electrodeposited aluminum. It consists of a heat-resistant transparent synthetic resin (butanol-modified melamine resin and maleic anhydride anhydride resin) and a dye dissolved in an organic solvent (acetone, ethyl acetate). After the coloration, it is coated on the surface of the shedding layer, and the silver color of the silver and the anodized aluminum is the same, and the silver color is the true color of the anodized aluminum, so the silvered anodized aluminum does not have this layer.

The fourth layer is an aluminized layer, which plays a role in increasing the gloss. The gaseous aluminum uniformly adheres to the surface of the colored layer under vacuum conditions. 

The fifth layer is the hot melt film, which consists of a hot melt adhesive. The different uses and models of galvanized aluminum foil are determined by this layer. 

The use of electro-aluminum is divided into hot stamping paper, lacquer, paint, plastic, and wood. 

Electrochemical aluminum quality standards: 1 uniform coloring, no visible color flower after hot stamping; 2 good brightness, color close to the standard sample;

3 tight structure, do not fall off powder. 

The quality standards of the galvanized aluminum primer: 1 The coating is uniform, smooth, white, and free from visible streaks; 2 The trachoma should be as small as possible, and the primer layer should be slightly dark, but it must not affect the quality of bronzing and the brightness of the color. 3 The brightness of the aluminum foil is good, and the hot stamping color does not change at a high temperature of 100°C. Fastness, durability, firmness, firmness, no powder, high definition, No. 4 and No. 5 hot stamping, graphic lines are not missing, and the writing is clear. 

The shelf life of anodized aluminum should not exceed two years. During storage, precautions should be taken to prevent heat, pressure, moisture, and direct sunlight. In particular, anodized aluminum should be protected against moisture. Each volume of anodized aluminum should be sealed with plastic to prevent the moisture in the air from corroding the anodized aluminum. After the tide is reached, the gold powder is detached very badly and cannot be used. 

Second, the relationship between printing pressure, temperature and hot stamping

    We all understand that hot stamping anodized aluminum must have two prerequisite pressures and temperatures.  Printing pressure is too small to meet the needs of the aluminum foil to adhere to the substrate. It is often easy to make hot stamping aluminum foil or hot stamping, but the printing pressure is too large, and it is easy to make the stamping and writing of the aluminum foil. Image stencil with dirty, thick, distortion, pressure, high temperature, so that zinc plate, copper plate printing rate is low. When the hot stamping temperature is low, the exfoliation layer and the hot melt film layer are not completely melted, and the hot stamping characters, lines, image imprints, or hot stamping may not be produced; however, if the temperature is too high, it will cause hot melt. The film layer is over-range melted, and the surface of the aluminized layer and the colored layer is oxidized, pasted and foamed, and the hot stamping product loses its metallic luster. The electro-aluminum hot stamping can only make the hot-melt adhesive in the hot-melt film work under the appropriate pressure and temperature, so that the electro-aluminum foil can better adhere to the printed paper, plastic, and linoleum. On the other hand, pressure and temperature have mutual influence and mutual restraint, but this relationship can only work within a certain range. For example, if the temperature is too low, even if the pressure of the printing hot stamping is large, it will be of no avail. On the contrary, if the temperature is high, the hot stamping pressure will not be sufficient. In addition, the time must be taken into consideration when stamping. The hot stamping time is slow, and the aluminum foil is heated for a long time, which makes it easy to paste the plate; the hot stamping time is short, the speed is fast, and the time for the aluminum foil to heat is also short, and the problem of hot stamping is not easy to occur. Therefore, we must adjust the pressure, temperature, and time for the aluminum foil hot stamping and make the three products take into account. 

Three, electro-aluminum hot stamping should pay attention to a few points

1 Aluminum hot stamping plate Under normal circumstances, with copper plate, zinc plate, resin plate and other plates, text, lines, patterns, four sides to keep clean and smooth, without dirty, no shortage of strokes, zinc, copper plate To be as deep as possible, the edge of the corroded zinc plate is even and smooth, with a slope of about 70°. Do not cause pitting. The photo resist is not degummed and requires leveling. The use of copper stamping hot stamping is best, followed by zinc, in order to avoid paste, in the design of hot stamping text, lines, patterns, bold letters or thick strokes, patterns easily paste version, the computer output should be reduced fine processing, hot stamping The lines are too thin and too small for easy hot stamping. Strokes need to be bold. When designing, consider the pressure of hot stamping and the effect of temperature on hot stamping. 
When faced with copper plate, zinc plate surface degumming, hard material scratches, and pen breaks, when bronzing is not smooth and clean, you can use fine charcoal to grind the surface, but you can't grind it too long, too deep to make the text, Lines, graphics, thickening, deformation of the drawbacks. 

2 There are many reasons why hot stamping is not possible. 1 The base ink layer is thick, and after multi-color overprinting, the ink is thick and bright. 2 During the printing process, various printing failures such as chalking and crystallization will directly affect the quality of the hot stamping of the aluminum foil. The imprinting powder means that after the imprint is dried, it can be gently rubbed to remove the ink pigment particles. Blot crystallization refers to the fact that the ink is drying too fast so that the next trace of ink is not overprinted and vitrification occurs on the surface. The reason for this is the excessive addition of dry oil, excessively thick ink layer, uneven printing pressure, and the like. Electro-aluminum adhesives do not adhere to the ink layer. 3 The ink layer contains wax material, which will affect the disadvantages of hot stamping. If the underneath ink of hot stamping is added with auxiliary materials such as de-bonding agent, bright lacquer, and bright oil, it contains liquid. Paraffin waxes and anodized aluminum hot melt adhesives are difficult to bond with wax-like substances even when pressure is applied at high temperatures. 4 Insufficient hot stamping pressure and low temperature. 5 Electro-aluminum models are not correct, or the quality is faulty.

3 The most common fault in hot stamping is gluing. When you encounter such problems, you must analyze and treat them differently. It is the temperature problem to reduce the temperature, the pressure is too much, to adjust the pressure, there are quality problems in the aluminum, it is promptly replaced, the plate is high temperature extrusion deformation, change the paste, wear must be exchanged.
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4  bronzing below the background color, the background color should not be too thick, too much ink overprint, the ink should not be added oil, kerosene non-drying oils, to avoid the underlying ink layer too much oil, hot stamping problems , In this case, you can wipe it with absolute alcohol, or wipe it with a damp cloth and wipe it with magnesium carbonate to wipe away the wax and crystallized layer. 

5. If the writing is heavy on the 5th hot stamping, slightly paste version, the temperature should be properly lowered, and at the same time pay attention to less empty and reduce the unnecessary stop in the middle, otherwise it is easy to increase the heat of the hot plate, to stop the electricity, heat temperature Adjust to 20 ~ 30 °C, or pull the switch off, because the electric temperature is too high, it is easy to burn the kraft paper and pad on the platform. 

6 hot stamping plastic skin, notebooks, phone books and other products, often not the phenomenon of hot stamping, this is due to the increase in plasticizer plastic, plastic surface attached to a layer of oil, or wax layer, Very smooth and smooth, so it is best to use absolute alcohol wipe, hot stamping edges, in order to adapt to plastic bronzing, plastic manufacturers improve the production of imitation sheepskin, imitation cloth and other varieties of plastic, are conducive to hot stamping.
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7 hardcover book cover, back cover, and data compilation, due to the hardcover lock binding bound book cover, are using lacquer cloth as the printing material, fiber cloth coated with a layer of paint of various colors, called paint cloth, first To get a good size material from the paper cutter, because the cloth is soft and rolled, and it has certain shrinkage characteristics, the depth of corrosion of the copper plate and zinc plate must be as deep as possible. The text is best not to use boldface, lines, There must be a certain gap between the patterns, so as to avoid hot stamping paste, grasp the temperature and pressure, and bronzing time, lacquer cloth is soft and curly, hot stamping place should be accurate, rules, to avoid the emergence of dipping material, not Correct, gilt with dirty places, can be wiped clean with cotton wool deodorizer, you can also use a knife to gently scrape dirt.