Self-adhesive labels are a material widely used in many aspects such as life and work. There are also various stamping processes for self-adhesive labels. This article summarizes the use of self-adhesive labels in different mechanical platforms. The characteristics of adhesive hot stamping and self-adhesive hot stamping are first and then hot stamping. It includes a variety of hot stamping processes: cold hot stamping, round hot stamping, flat hot stamping, process characteristics and adaptable methods.
1． Hot stamping method
According to the processing method of self-adhesive labels, the hot stamping method is divided into sheet-fed hot stamping and web-fed hot stamping. Sheet-fed hot stamping is the same as the traditional hot stamping process and is processed on a special hot stamping machine. Web foil stamping is completed on a label linkage machine and is the most widely used processing method. At present, there are several methods for hot stamping roll materials:
① Flat stamping on label machines
Whether the letterpress label printing machine is a flat or round flat type equipment, due to the The web is fed intermittently, so all hot stamping uses flat pressing. Generally, the hot stamping station is an independent unit. There are also some models that use one unit for hot stamping and die cutting, which can be used separately.
②Multi-station flat stamping
Some models have two-station hot stamping units, such as Japan’s Shiki SMHC-45-MWL label machine, one of which is close to The printing plate is used to complete the horizontal hot stamping, and the other unit is an independent unit to complete the longitudinal hot stamping. This model can perform two-color hot stamping at the same time.
③ Flat stamping on the processing machine
The processing machine is specially designed for processing printed roll labels and labels that do not require printing. Hot stamping is a function of the processing machine. The hot stamping device on the processing machine generally adopts the flat pressing method, and its working principle is the same as the above-mentioned label machine.
④Circular hot stamping on a rotary machine
The hot stamping plate used in circular hot stamping is in the shape of a roller. During hot stamping, it is in rolling contact with the impression roller to achieve hot stamping. Round press round hot stamping is suitable for use on rotary label machines that continuously feed paper, but it has certain requirements for paper feeding speed, which means it has an impact on printing speed. But compared with flat pressing and hot stamping, the efficiency is greatly improved. The manufacturing cost of round press round hot stamping roller is high, so it is only suitable for long version hot stamping.
⑤Cold foil stamping on a rotary machine
This is a new foil stamping process that no longer uses a heated metal printing plate, but uses a printing adhesive to make the metal foil Transfer to achieve hot stamping. The process flow is: first print a UV pressure-sensitive adhesive on the location where the printed product needs to be hot stamped, dry the adhesive through a UV drying device, then use a special metal foil to compound the pressure-sensitive adhesive, and then peel off the metal foil, so the metal The part of the foil that needs to be transferred is transferred to the surface of the printed matter to achieve cold foil stamping. The cold foil stamping process has low cost, saves energy, and has high production efficiency. It can use existing equipment components without adding additional devices. It is a promising new process.
2. Hot stamping first and then hot stamping
The hot stamping of self-adhesive adhesive can also be divided into first hot stamping and last hot stamping. First hot stamping means hot stamping on the label machine first, and then printing; and later hot stamping means printing first and then hot stamping last. . The key to hot stamping first and hot stamping later is the drying of the ink. There are two situations in the relationship between hot stamping patterns and printed patterns: juxtaposition and overprinting. Due to the different inks used, label printing requires two processes: first hot stamping and last hot stamping.
①First hot stamping process
When printing labels with ordinary ink on a label machine with intermittent paper feeding and hot stamping components installed in front, the first hot stamping process is used because the ink used is oxidized. In the polymerization drying type, it takes a certain amount of time for the ink layer to dry completely after printing, so the hot stamping pattern must avoid the ink. The best way to avoid ink is to pre-foil the web material and then print it.
The first hot stamping process requires that the printing pattern and the hot stamping pattern are separated (parallel), because the surface of anodized aluminum is smooth, does not contain ink, and cannot be printed. Hot stamping first can prevent ink from smearing and ensure the quality of label printing.
②Post-hot stamping process
The post-hot stamping process is applied to the label machine where the hot stamping parts are installed on the back door, and UV ink is used for printing. The web material is first printed and passes through a UV drying device to instantly dry the ink, and then hot stamping is applied to the surface of the material or ink after the ink has dried.
Since the ink has dried, the hot stamping pattern and the printed pattern can be printed side by side or overlapping without ink smearing.
Of the two hot stamping methods, post-hot stamping is the more ideal method. It also brings convenience to label pattern design and expands the application range of hot stamping patterns. However, due to the limitations of equipment functions, the cost of label printing is relatively high. The hot stamping process is suitable for processing small labels with simple patterns. It has low cost and wide application range. It is a commonly used method in small and medium-sized printing factories.
The difference between hot stamping methods
Hot stamping, as an important metal effect surface decoration method, is an effective way to enhance the visual effect of trademarks, cartons, labels and other products, and is widely used. . The two main hot stamping methods, hot stamping and cold stamping, each have their own advantages and disadvantages. In practical applications, the appropriate hot stamping method should be selected according to specific circumstances, mainly based on cost and quality considerations. Advantages of thermal stamping technology (1) Good quality, high precision, clear and sharp edges of the stamped image. (2) The surface has high gloss and the hot stamping pattern is bright and smooth. (3) There is a wide range of hot stamping foil options, such as different colors or different gloss effects, as well as hot stamping foils suitable for different substrates. (4) Three-dimensional hot stamping can be performed. Advantages of cold stamping technology (1) There is no need to purchase expensive specialized stamping equipment. (2) Ordinary flexographic plates can be used, and there is no need to make metal hot stamping plates. The plate making speed is fast, the cycle is short, and the production cost of hot stamping plates is low. (3) The hot stamping speed is fast, up to 450fpm. (4) No heating device is required, saving energy. In actual production, should we choose hot stamping technology or cold stamping technology? The answer is: it should depend on the specific circumstances. Using thermal stamping technology can achieve the best stamping quality and effect, but the cost is higher. Although the quality of cold stamping is also good, it is inferior to hot stamping, but the cost is lower.