With the improvement of the national economy and the development of the printing and packaging industry, people demand the packaging of products: high-end, exquisite, environmentally friendly, and personalized. In the post-press processing of packaging products, the electro-aluminum hot stamping process is favored by people for its unique surface finishing effect, and has application in high-end packaging such as banknotes, cigarette labels, medicines, and cosmetics. Electro-aluminum hot stamping refers to hot stamping, hot silver stamping and other hot stamping material hot stamping processes. In order to facilitate discussion, the following is the general name of hot stamping aluminum foil stamping. There are two main functions of bronzing: one is surface decoration, which increases the added value of the product. Hobbies and celebrations are the national traditions of our country. The combination of bronzing and embossing techniques is used to highlight its luxury. The second is to give the products higher security performance. The holographic orientation is used to stamp the trademark logo to prevent counterfeiting and brand names. At the same time, bronzing is very capable of representing the individualization of product packaging and is safe and environmentally friendly. Therefore, many high-end packaging has adopted the bronzing process. How to improve the quality of bronzing? This article discusses from the following aspects. High-quality hot stamping is the primary factor that guarantees the quality of stamping. At present, bronzing plates are mainly produced by photographic etching techniques and electronic engraving techniques. The materials are often used for copper plates or zinc plates. Copper plate material is delicate, surface finish, heat transfer effect are better than zinc plate, the use of high-quality copper plate can increase the bronzing graphic gloss and outline definition. The traditional photographic corrosion technology makes the bronzing plate process simple and low cost, mainly used for text, thick lines, general images; for the finer, uneven thickness of text and graphics, etc. need to use the second rotten or electric carving technology. Electric carving production bronzing version can express rich and delicate level changes, greatly expanding the performance of the packaging, the process is conducive to environmental protection, but the electric carving equipment investment is relatively large, the depth of the current sculpture is not ideal, easy to cause hot stamping "glue". Holographic anti-counterfeit stamping production technology requirements are relatively high. Previously, they were mainly produced in Taiwan or abroad, and the plate making cycle was long. It was only used for the packaging of fixed and large-volume products. Second, bronzing equipment "If a worker wants to do good, he must first sharpen his tools." The selection of bronzing equipment is a key factor in determining the quality of bronzing. Sheetfoil hot stamping machine has flat pressing, round flat pressing and round pressing. There are three types of flat pressing machines at present. The main applications are: Shanghai Yahua Printing Machinery Co., Ltd. TYM series die cutting hot stamping two Machine, Tangshan Yuyin Group's TYMl020 automatic bronzing die-cutting machine, Tianjin Hengheng Machinery Industry's MK series automatic bronzing die-cutting machine, the highest bronzing speed is 5000 sheets/hour. STEUER FOLLJET FBRl04 hot stamping machine is represented by round press circle. Using the design concept of offset press, the maximum hot stamping speed can reach 10000 sheets/hour. At present, it is the fastest equipment for international sheet-fed stamping. Round press, round press and flat press Three types of embossing hot stamping machines have their own advantages and disadvantages: Round press round and round press Hot press implementation is line pressure, total pressure is small, easy to complete with relatively small pressure A large area of ​​gilding in the field, smooth movement, and high round-round production efficiency, especially for large quantities of live stamping, but due to the difficulty of copper circular surface processing, higher production costs, heating roller than flat heating is difficult. Flat press operation is flexible and convenient, and it is more suitable for short version products. Domestic bronzing equipment has obvious advantages in terms of performance and price compared with imported gilding equipment. The price of domestic machines is only equivalent to l/5~1/4 of the price of similar foreign products, but the overprint accuracy, stability, and function of imported machines are all high. Obviously better than the domestic machine, but also more durable than the domestic machine, more suitable for fixed bulk high-grade packaging products processing. Therefore, the product type and lot size are the key factors that determine the selection of bronzing equipment. Whether it has high-end stamping equipment such as BOBST has become the preferred condition for customers in the industry. Third, bronzing suitability The so-called bronzing suitability refers to the matching of the type of galvanized aluminum and the factors such as bronzing speed, temperature and pressure. In the case of fixed hardware such as equipment, proper control of bronzing suitability is the most important means to improve bronzing quality. The following analysis of some of the quality issues reflected in the actual operation, in order to scientifically grasp the bronzing nature. 1. Hot stamping is not true or hot stamping is not true This is related to the surface characteristics of the print, the nature of the electro-aluminum, the hot stamping temperature and pressure and other factors. 1 The surface of the print is dusted too much or the surface contains additives such as a releasant and a bright paste, which will hinder the adsorption of the aluminum foil and the paper. The solution: surface powder removal or solution in the printing process. 2 The improper use of anodized aluminum directly affects the fastness of hot stamping. According to the size of the bronzing area, the characteristics of the stamped material should be considered in consideration of what type of galvanized aluminum is selected. Domestic aluminum products are mainly peacock brand series produced by Shanghai Shenyong Hot Stamping Material Co., Ltd., and imported aluminum products are mainly PMK and LK series from Germany KURZ, Japan's A, K and H series, and KOLON's SP series from South Korea. . According to our practice and testing, the matching of the electro-aluminum is mainly based on the following classifications: Bronzing on general products (generally black) Electro-aluminum on type 88-l, KURZ PM; cigarettes, cosmetics and other dark ink printed matter (including printing Gold- and silver-and-silver-based foils are type 88-2; foils, cosmetic packaging, and other fine-grained stamped foils are 88-3, 88-4, PM288, etc.; suitable for OPP or PET laminated papers. And there are UV ink paperboard, glazing paper and other products hot stamping electroformed aluminum 88-4 type, K series, LK series, and SP series. 3 The correct match between the hot stamping equipment and the hot stamping time and the stamping temperature is not grasped, which affects the fastness of the stamping and the sharpness of the graphic outline. Due to the different equipment and hot stamping materials, the hot pressing time and hot stamping temperature are not the same. For example, a high-speed circular press has a fast speed and the embossing line contacts. The hot stamping temperature is higher than that of a round press or a flat press. Under normal circumstances, round press hot stamping temperature is 190 °C ~ 20 °C, round flattening about 130 °C ~ 150 °C, flattening about 100 °C ~ 20 °C. Of course, hot pressing time, hot stamping temperature and production efficiency are also largely constrained by the transferability of the electro-aluminum. 2. Pull back Reverse pulling refers to that after the hot stamping, the electro-aluminum pulls the printing ink or the printing oil on the printing. The main reason is that the ink on the surface of the printed product is not dry or the post-processing of the surface of the printed product is improperly processed, which results in the ink on the surface of the printed product, the UV oil and the surface of the paper are not firmly bonded together. Solution: After the prints are dried and then hot gold. In addition, it is possible to use electro-aluminum with low electro-aluminum separation and excellent heat transfer. 3. Paste plate and electrochromic discoloration after hot stamping The paste version is mainly caused by the poor production of the hot stamping version, the looseness of the installed aluminum foil, or the incorrect foiling of the aluminum foil. After the stamping, the discoloration of the electro-aluminum is mainly due to the high stamping temperature. In addition, the wrinkling of the aluminum foil is also likely to cause discoloration due to uneven color stamping, which can be solved by appropriately lowering the temperature. For the round-flattening model, fans can be installed at the foil feeding place to keep the foils from floating, avoiding the aluminum foil touching the hot stamping and scorching before the stamping. 4. The improper arrangement of the process destroys the luster of the surface of the electro-aluminum, and the outline of the graphic is confusing. In the bronzing process that requires lamination, people often worry that the gold foil will be easily wiped off and then hot stamped and then laminated. This can easily lead to: 1 The film (especially the matt film) will destroy the luster of the surface of the electrodeposited aluminum. It is not appropriate to use water-soluble glue to cover the film. Otherwise, the surface of the electrodeposited aluminum will be blackened, and the powder will easily stick to the edges of the picture and cause the phenomenon of hair crazing. 2 After the bronzing, the dent is caused by the pressure, and the glue is not easy to penetrate the surface of the galvanized aluminum, which can easily cause separation of the OPP from the bronzing office and affect the product quality. The correct process is to apply foil and then hot stamping, choose the matching of aluminum and OPP.
First, bronzing version
At present, there are several units that can be produced in Shanxi Yuncheng, Beijing and Shanghai.
In short, there are many factors that affect the quality of bronzing. Making high-quality bronzing plates and correctly grasping bronzing suitability are the key to improving the quality of bronzing.
Source of information: China Yinguang