How to improve the hot stamping quality of hot stamping foil?

As we wall know that temperature,stamping pressure and foiling time are the basic element of hot foil stamping,which will decide if the hot foil stamping is perfect, in addition, the quality of raw materials related to hot stamping must also be guaranteed, such as: the hot stamping suitability of the substrate , The performance of the anodized aluminum material and the quality of the hot stamping plate, etc. If something goes wrong in a certain link, it will definitely affect the final hot stamping effect.

Choose the right substrate. There are many substrates that can be bronzed, usually paper, such as: coated paper, white paper, white cardboard, cloth paper, offset paper, and so on. But not all paper bronzing effects are ideal. If the surface is rough and the paper is loose, such as book paper, poor offset paper, etc., because the anodized aluminum layer cannot adhere to the surface well, the unique metal The gloss cannot be reflected well, and it may even fail to be hot stamped. Therefore, the hot stamping substrate should be made of paper with dense texture, high smoothness and strong surface strength, so that a good hot stamping effect can be obtained, and the unique anodized aluminum The gloss is fully reflected.

Choose the appropriate anodized aluminum model according to the different substrates. The structure of anodized aluminum has 5 layers, namely: polyester film layer, peeling layer, color layer (protective layer), aluminum layer and glue layer. There are many types of anodized aluminum, the common ones are No. 1, No. 2, No. 8, No. 12, No. 15 and so on. In addition to gold, there are dozens of colors, such as silver, blue, brown-red, green, and red. Choosing anodized aluminum should not only choose the right color, but also choose the corresponding model according to the different substrates. Different models have different performances and the range of materials suitable for ironing. Normally, No. 8 is the most used hot stamping for paper products, because No. 8 anodized aluminum has moderate adhesion and good gloss, which is more suitable for hot stamping on general printing paper or glazing paper and varnished cloth. If you are hot stamping on hard plastic, you should choose other corresponding models, such as No. 15 anodized aluminum.

The quality of anodized aluminum is mainly checked by visual inspection and hand feeling, such as checking the color, brightness and trachoma of anodized aluminum. Good quality anodized aluminum requires uniform color, smooth and clean after hot stamping, and no trachoma. The fastness and tightness of the anodized aluminum can generally be checked by rubbing it by hand, or trying to stick the surface layer with transparent tape. If the anodized aluminum does not fall off easily, it indicates that the fastness and tightness are good, and it is more suitable for hot stamping small text patterns, and it is not easy to paste the plate during hot stamping; if the anodized aluminum falls off after being gently rubbed, it indicates that its tightness is poor. It can be used for hot stamping with sparse graphics and text; in addition, pay attention to the broken ends of anodized aluminum, the less the broken ends, the better. It is worth noting that the anodized aluminum must be stored properly. It should be stored in a ventilated and dry place. It cannot be mixed with acids, alkalis, alcohols and other substances. It must be protected from moisture, high temperature, and sun. Otherwise, the aluminum will shorten Period of use.

Make a good hot stamping plate. Hot stamping plates generally include copper plate, zinc plate and resin plate. Relatively speaking, the copper plate is the best, the zinc plate is moderate, and the resin plate is slightly worse. Therefore, for fine hot stamping, copperplate should be used as much as possible. For the hot stamping plate, it is required to have a smooth surface, clear graphics and text lines, smooth edges, and no pitting and burrs. If the surface is slightly uneven or slightly scratched or fluffy, use fine charcoal to gently wipe it to make it smooth. The corrosion of the hot stamping plate should be slightly deeper, at least 0.6mm or more, and the slope should be about 70° to ensure clear hot stamping graphics, reduce the appearance of contiguous and stale plates, and improve the printing resistance rate. The design of hot stamping text, lines and patterns is very particular. The graphics and texts should be as thick as possible, and the density should be reasonable. If it is too small or too thin, it will be easy to miss the strokes; if it is too thick and too dense, it will be easy to paste. Control the hot stamping temperature. The hot-stamping temperature has a great influence on the melting degree of the hot-melt silicone resin peeling layer and the adhesive. The hot-stamping temperature must not be lower than the lower limit of the anodized aluminum temperature resistance range, which is the minimum temperature to ensure the melting of the anodized aluminum adhesive layer.

If the temperature is too low, the melting will not be sufficient, it will cause the hot stamping or the hot stamping is not strong, and the imprint will not be strong, incomplete, lack of strokes or scratches; while the temperature is too high, the melting will be excessive, resulting in adhesion around the imprint The anodized aluminum also melts and falls off to produce a paste. At the same time, the high temperature will oxidize and polymerize the synthetic resin and dye in the color layer, which will cause blistering or fogging in the print, and cause the surface of the aluminum layer and the protective layer to oxidize, which reduces the hot stamping product. Brightness or loss of metallic luster. Generally speaking, the electric heating temperature should be adjusted between 80～180℃. For larger hot stamping area, the electric heating temperature is relatively higher; otherwise, it is lower. The specific situation should be determined according to various factors such as the actual temperature of the printing plate, the type of anodized aluminum, the graphics and text conditions, and the most suitable temperature is usually found through trial ironing. The temperature should be the lowest and clear graphics and text lines can be imprinted. As the standard.

It is necessary to reasonably control the hot stamping pressure. The hot stamping pressure has a great relationship with the adhesion fastness of anodized aluminum. Even if the temperature is right, if the pressure is not enough, the anodized aluminum will not stick firmly to the substrate, or cause color fading, imprinting, etc.; on the contrary, if the pressure is too high, the compression deformation of the liner and the substrate will be too large, resulting in paste The plate or print becomes thicker. Therefore, the hot stamping pressure should be adjusted carefully.

When setting the stamping pressure, the main considerations should be: the properties of anodized aluminum, the stamping temperature, the stamping speed, the substrate, etc. Generally speaking, if the paper is strong, smooth, the ink layer printed is thick, and the hot stamping temperature is high and the speed of the car is slow, the stamping pressure should be lower; on the contrary, it should be higher. In addition, similar to the hot stamping liner, you should also pay attention to it. For smooth paper, such as coated paper and glass paper, it is best to use hard liner paper, so that the print will be clearer; on the contrary, for poor smoothness , For rougher paper, the liner should be softer, especially when the hot stamping area is larger. In addition, the hot stamping pressure must be even. If it is found that the hot stamping cannot be performed locally or tingling occurs during the trial printing, it may be that the pressure here is uneven. You can pad thin paper on the flat plate at the place and make appropriate adjustments.

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