Basic introduction Chinese name: [bronzing]: mbth: bronzing pinyin: tàng jρn Athena Chu: ?ㄤㄐㄧㄣ definition, basic explanation, citation explanation, basic concept, overview, characteristics, product application, matters needing attention, storage conditions, technology and technical principles. Quoting explanation is also called "bronzing". A printing decoration process. Heat the metal printing plate, paste the foil, and imprint gold words or patterns on the printed matter. Xu Chi's "Seeking the Peak": "He stood up, opened the suitcase under the window and took out a stack of four hardcover books gilded with red silk." Selected Novels, No.2, 198 1: "He took out two work permits from his coat pocket, broke the gold-plated red plastic skin and glanced at it." The basic concepts are summarized as follows: book cover bronzing, gift box bronzing, tobacco and alcohol clothing trademark and packaging box bronzing, greeting cards, invitations, pens bronzing, etc. There are many colors and patterns, and the special edition can be customized according to specific requirements. The base materials of hot stamping are ordinary paper, printing paper with gold and silver ink, plastics (PE, PP, PVC, ABS and other engineering plastics, etc. ), leather, wood and other special materials. Galvanized aluminum hot stamping foil mainly uses heat and pressure to transfer patterns or characters to the surface of hot stamping materials. In order to complete this process, a bronzing machine and a bronzing template (such as zinc plate, copper plate, silicone offset printing plate, etc.) are needed. ) engraved with special words or patterns need to be heated to the required temperature, transfer the required pressure and maintain the corresponding time. Features: clear and beautiful patterns, bright colors, wear resistance and weather resistance. In the printed cigarette labels, the application of bronzing technology accounts for more than 85%. In graphic design, bronzing can make the finishing point and highlight the design theme, especially for trademarks and registered names. The product should be 1. Ordinary gold and laser gold bronzing. It can be used for hot stamping on most products, including gold cards, silver cards, laser cards and glass cards, and is widely used. Related products 2. Positioning holographic bronzing. Holographic laser positioning anodized aluminum is a special technological application in design, with corresponding anti-counterfeiting patterns, which can greatly improve the anti-counterfeiting ability and quality of products. This kind of anodic alumina is generally produced in China. Compared with imported goods, the price is cheaper, but the bronzing performance is slightly worse. The location of anodized by holographic laser is closely related to the control of hot stamping temperature, hot stamping pressure, vehicle speed and even hot stamping model. 3. Special application of anodic oxidation in the process. Printing after ironing is a new idea for cigarette label design and printing industry. The application of this process has high requirements for anodic alumina. 4. gilding directly on the surface of UV varnish. The process itself has very high requirements for UV varnish and bronzing anodized aluminum. Pay attention to control the oil quantity when applying varnish, and try to ensure that the varnish coating of the whole batch of products is relatively stable, and the oil layer should be thin and flat. For anodized aluminum used for bronzing, it requires high temperature resistance, good adhesion and good adaptability to varnish bronzing (the resin type used in varnish matches the hot melt adhesive used in anodized aluminum bronzing). In all products, this process is applied in a small range. In addition, the bronzing of anodized aluminum on gold, silver ink and matte oil also has high requirements for bronzing surface and bronzing anodized aluminum. If the ink particles on the bronzing surface are large or the surface is rough, it will directly affect the normal bronzing. Note: 1. It is necessary to select the appropriate hot stamping foil according to the different varieties of the object to be ironed. When hot stamping, we must master the coordination of temperature, pressure and hot stamping speed, which is different according to the different hot stamping materials and hot stamping areas. 2. When cutting, we should master the speed and direction of turning tool. 3. The electrochemical aluminum foil for hot stamping should be made of paper, ink (especially black ink), kerosene, compound glue and other materials, and the hot stamping parts must be kept dry to avoid oxidation or damage to the bronzing layer. 4. The general packaging is: 64CM× 120M, with one box for each 10 roll; The width is 64CM, the length is 120M or 360m or other special specifications (1.5m, the width is 1000m or the length is 3000m). 5. When stored, it should be placed upright, pressure-proof, moisture-proof, heat-proof and sun-proof, and placed in a cool and ventilated place. Storage conditions (1) Temperature 5℃-20℃ (2) Humidity 30-70% (3) Vertical storage (4) Avoid direct sunlight. Cloth bronzing technology has developed rapidly in China, but it was really put into large-scale industrial production after 2000. With the rapid development of science and technology, the bronzing process of cloth is becoming more and more mature. Because the overall effect of bronzing cloth is elegant and trendy, it is more and more loved by many beauty lovers. With the continuous development and update of bronzing technology, cloth bronzing has been subdivided into different industries. Taking bronzing equipment and bronzing methods as examples, there are two common bronzing equipment: (1) rotary cloth bronzing:
Both the stamping plate and the bottom die release plate are cylindrical, and there is linear contact between the two cylindrical rollers. The bottom die relief plate is generally made of silicone material with moderate hardness. This bronzing machine is suitable for bronzing the whole narrow roll of cloth strips. Its advantages are high speed and high output. Usually, the gilding paper it uses has its own gilding glue besides the metal coating on the back. As long as the gold paper is selected properly and the performance of the bronzing machine is debugged accurately, the fastness of the cloth after bronzing is basically ok. However, this method also has a disadvantage. Because the cloth has some tension more or less, during the whole roll of cloth bronzing, both the cloth and the bronzing paper move at the same time. When doing multi-color bronzing, the accuracy of color matching is not well controlled. At this time, we can only settle for the second best, first do a good job of monochrome bronzing, and achieve the ultimate. (2) flat cloth bronzing:
Common bronzing machines are: pneumatic bronzing machine or manual bronzing machine, and the main components are composed of upper and lower metal plates. When doing cloth bronzing, the aluminum plate at the top usually heats up and moves down. The pressure and time to be considered when bronzing depend on the height of the adhesive layer of the printed pattern and the temperature that the cloth can withstand. In most cases, the temperature is 140 ~ 160, the pressure is above 5kg, and the time is 10 second (reference value). The temperature is too low, and the hot stamping fastness is not ideal; On the contrary, after the cloth is bronzed, the cloth surface turns red (white cloth turns yellow) and becomes discolored. Too low pressure will affect the fastness; Too high, the pattern of three-dimensional gilding paste collapses, losing the three-dimensional effect. When using this method to do cloth bronzing, there is a premise: add bronzing glue to the screen, print the pattern you need on the surface of the cloth in advance, and then go into the bronzing machine to do cloth bronzing after it is completely dried. After bronzing, let it cool completely, tear off the waste gold foil → check → repair → package, and complete the bronzing process of the whole cloth. There are many technical points in cloth bronzing process, and it is unlikely that it can be simply summarized in just a few pages and articles. To achieve good bronzing fastness and feel, it is necessary to accumulate certain technical content and operating experience. Only by constantly exploring and making progress can we open up fertile soil and oasis for cloth bronzing. Cloth bronzing technology is not the best, only better! Process principle The bronzing process is to transfer the aluminum layer in anodized aluminum to the surface of the substrate by using the principle of hot pressing transfer, forming a special metal effect. Because the main material used in bronzing is anodized aluminum foil, bronzing is also called anodized hot stamping. Electrochemical aluminum foil is usually composed of multilayer materials, and the substrate is often P E, followed by separation coating, color coating, metal coating (aluminum plating) and glue coating. The basic process of bronzing is that under pressure, that is, anodic aluminum oxide is pressed by the hot stamping plate and the substrate, the hot-melt silicone layer and adhesive on anodic aluminum oxide are melted by heating, and the viscosity of the heated silicone decreases, while the viscosity of the special heat-sensitive adhesive increases after heating and melting, so that the aluminum layer is peeled off from the anodic aluminum oxide base film and transferred to the substrate at the same time. With the removal of pressure, the adhesive quickly cooled and solidified, and the aluminum layer was firmly attached to the substrate, completing the hot stamping process. There are two main functions of bronzing: first, surface decoration can improve the added value of products. The combination of bronzing and embossing technology and other processing methods can show a strong decorative effect of the product. The second is to give the product higher anti-counterfeiting performance, such as using holographic positioning to imprint the trademark logo. After bronzing, the product has clear pattern, beautiful appearance, bright color, wear resistance and weather resistance. At present, the bronzing process on printed cigarette labels accounts for more than 85%. In graphic design, bronzing can make the finishing point and highlight the design theme, which is especially suitable for the decoration of trademarks and registered names. Overview of technical development In recent years, with the improvement of the processing level of bronzing materials and bronzing plates and the use of new machinery and equipment, domestic bronzing technology has also made some new developments. High-speed hot stamping, three-dimensional hot stamping, holographic positioning hot stamping and post-hot stamping printing have been widely used in the production of cigarette packs. Three-dimensional bronzing Three-dimensional bronzing: Three-dimensional bronzing technology is a composite technology combining bronzing technology and embossing technology. It is a technological process that bronzing and embossing graphics and texts are made into female die intaglio and male mold relief with matching up and down by using corrosion or engraving technology, and the bronzing and concave-convex embossing processes are realized at one time. This process completes bronzing and embossing at the same time, which reduces the waste products caused by processing procedures and overprinting and improves production efficiency and product quality. Because the product effect formed by three-dimensional bronzing is a relief-like three-dimensional pattern, it can no longer be printed on it, so the process design of printing first and then ironing must be adopted, and because of its high precision and high quality requirements, it is not suitable for cold stamping process. Three-dimensional bronzing equipment usually has two types: flat pressing and round pressing, and round pressing is not suitable for three-dimensional bronzing. Rotary hot stamping is usually used for online processing of web. Because the circular pressing is in line contact, the bubble phenomenon that may exist in flat pressing can be completely avoided, with high speed and good quality. However, because both the hot stamping plate and the bottom die relief plate are round, the processing is difficult and the cost is high, and the heat transfer effect of the round hot stamping plate is not very ideal, so it is not widely used, and it is mostly used in some products with large long-term output and high quality, such as cigarette packs, wine packs, health care products and so on. Due to the popular soft packaging form of high-grade cigarettes, the mature post-press processing technology originally applied to white cardboard has also been transferred to soft paper. Embossing and positioning ironing of soft paper is a process of combining stamping and embossing. The product has the characteristics of full bronzing, fine graphics and text, beautiful appearance and no embossing skew. However, this process is technically difficult, and the precision requirements for hot stamping plates, holographic films and bronzing machines are particularly high, and all operating indicators are very strict. Because of this, it is difficult to be imitated and has a high degree of anti-counterfeiting. Hologram bronzing Hologram bronzing: The laser hologram is made by spatial frequency coding according to the principle of laser interference. Laser hologram is widely used in the field of anti-counterfeiting because of its good color, obvious layering, realistic image, good optical conversion effect and high information technology content. The latest optical variable pattern technology is obviously different from the widely used holograms (three-dimensional holograms), and some holograms have the function of machine recognition. The mechanism of holographic hot stamping is that the hot melt adhesive layer and separation layer on the holographic hot stamping material are heated and melted by the hot stamping die heated on the hot stamping equipment, and the holographic grating stripes of the information layer of the hot stamping material are separated from the PET substrate under a certain pressure, so that the aluminum foil information layer and the hot stamping surface are bonded into a whole to achieve perfect combination. Holographic hot stamping mainly includes ordinary hot stamping and positioning hot stamping. Among them, special edition holographic positioning hot stamping has frequently appeared on high-grade cigarette cases in recent two years. It means that the hologram of a specific part of the holographic anti-counterfeiting hot stamping anodized is accurately hot stamped on the specific position of the cigarette pack by photoelectric identification on the hot stamping equipment. Holographic positioning ironing technology is very difficult, which requires not only the printing factory to be equipped with high-performance and high-precision special positioning ironing equipment, but also high-quality special positioning bronzing anodized aluminum, and the production process must be strictly controlled to produce qualified cigarette packs. Cold stamping technology Cold stamping technology: Cold stamping technology is the first new technical achievement applied in the printing industry in Europe and America in recent years, which is to complete the transfer of electrochemical aluminum foil under cold pressure. Special anodized aluminum is used for cold stamping, and the back is not coated with glue. When printing, the glue is directly coated on the position that needs decoration. During transfer printing, anodic aluminum oxide is attached to the surface of printed matter under the action of adhesive. The cold stamping process prints UV ink first. After drying, the special UV curing adhesive is printed on the part of the ink surface that needs bronzing; Then the moisture in the adhesive is evaporated by UV drying device to form a thin pressure-sensitive adhesive layer with high viscosity. Then, under the action of a pair of metal rollers, the aluminum foil contacts the adhesive and is pressed into a whole. Because of the strong adhesion between the adhesive and the aluminum foil, when the waste is discharged, the part of the aluminum foil that contacts the adhesive remains on the surface of the printed matter and blends with the printed matter, while the other parts of the aluminum foil are discharged like traditional bronzing, thus completing the first part of the bronzing process. Because the aluminum foil pattern transferred to the printed matter floats on the surface of the printed matter and has poor firmness, it is necessary to polish or cover the surface of the printed matter to protect the aluminum foil pattern. Compared with the traditional bronzing process, the cold bronzing process is fast and energy-saving: the material has a wide range of applications and can be used for cold bronzing on thermal paper and some film materials. Replacing the expensive metal plate roller with ordinary flexographic plate greatly reduces the production cost and cycle of bronzing plate, and also reduces the pollution in the process of metal plate corrosion. The cold stamping process is limited by adhesive, metal foil and other conditions, but there are also some shortcomings, such as: after cold stamping, the printed matter must be glazed or covered with film to protect the stamping pattern, which increases the cost and complexity of the process. Cold stamping process is not suitable for PVC, PE and other film materials with shrinkage characteristics. Due to the poor leveling of UV glue and the poor surface finish after drying, the brightness of the metal foil transferred on it is poor, and the diffuse reflection phenomenon appears, and the effect is not as good as that of the traditional hot stamping process. The key technologies of cold stamping process are UV glue and special anodized metal foil, which have broad development prospects. Hot stamping first and then printing: In recent years, some printing houses have introduced a new process of hot stamping anodized first and then printing patterns on anodized, which can make the theme of cigarette packets more lively. Printing after ironing is a new idea for cigarette label design and printing industry. The application of this process requires high anodized, and the key of the process is that anodized hot stamping must be firm, and anodized must never be pulled down by ink when printing. Reverse drawing not only affects the quality of cigarette packets, but also causes anodic aluminum oxide to quickly accumulate on the blanket, resulting in the loss of image dots and the inability to print local images. With the operation of the machine, anodic alumina powder will be transferred to the ink roller system, which will accelerate the wear of the ink roller. Therefore, according to the characteristics of printing paper, this process should choose appropriate anodized to ensure that anodized can firmly adhere to the paper surface. In production, in addition to the requirements of accurate stamping position, smooth and bright surface, uniform pressure, no foaming, no paste and so on. In addition, it is especially required that there should be no obvious indentation on the edge of stamping pattern, and the adhesion of anodized aluminum on the stamping surface should be good, and there should be no obvious scratches and scratches. As we all know, the bronzing process is actually a process in which paper is heated and pressed. For white cards and glass cards, special attention should be paid to the protection of semi-finished products, and various unfavorable factors of paper deformation should be reduced as much as possible in the production process, which is of great help to the smooth progress of stamping process and the improvement of product qualification rate. Micro-embossing technology Micro-embossing technology: This technology uses micro-embossing board to press out all kinds of fine lines on the graphic part of aluminum foil paper, and the products obtained have the effects of bronzing and embossing, and the metal texture is very strong. At present, although various new bronzing processes emerge in endlessly, the traditional anodic oxidation hot bronzing technology, as an important process in post-press processing, has not been ignored because of its unique decorative effect and mature process operation, but has attracted more attention and favor. The traditional hot-pressed anodic oxidation foil mainly uses heat and pressure to transfer patterns or characters to the surface of hot stamping materials. To complete this process, you need a bronzing machine, a template engraved with special words or patterns, the temperature required for heating, the pressure required for transfer printing and the corresponding time. It should be noted that when hot stamping different materials, it is necessary to choose the appropriate model of anodized and the appropriate temperature, pressure and hot stamping time to achieve the ideal hot stamping effect. Hot stamping plate: high-quality hot stamping plate is the primary factor to ensure the quality of hot stamping. At present, the production of bronzing plate mainly adopts photographic etching process and electronic engraving technology, and the material is mostly copper plate or zinc plate. Copper plate is fine in material, and its surface smoothness and heat transfer effect are better than zinc plate. The use of high-quality copper plate can improve the gloss and outline clarity of bronzing graphics and texts. The traditional photo etching technology is simple in process, low in cost and short in service life, and is mainly used for bronzing characters, thick lines and general images. For bronzing plates with fine and uneven graphic thickness, secondary etching or electronic engraving technology is needed. The bronzing plate made by electric carving can show rich and delicate level changes, which greatly expands the performance ability of packaging. This process is beneficial to environmental protection, but the investment of electric engraving equipment is large, and the current engraving depth is not ideal, which is easy to cause bronzing "paste version", but its printing resistance is high, which is suitable for long-version live parts of cigarette packs. Holographic anti-counterfeiting bronzing plate has high technical requirements and long plate-making cycle, and is only used for packaging fixed and mass products. Adaptability The so-called bronzing adaptability refers to the selection of anodized model and the matching of bronzing speed, temperature and pressure. Under the condition of fixed equipment and other hardware, mastering stamping suitability correctly is the most important means to improve stamping quality. The technological process of hot stamping is: preparing hot stamping plates, adjusting the technological parameters of hot stamping, trying hot stamping, signing samples and officially hot stamping. It can be seen from the process of bronzing that the three basic elements of bronzing are: temperature, pressure and hot stamping time. In order to obtain the ideal hot stamping effect, we must master the process parameters such as hot stamping temperature, hot stamping pressure and hot stamping speed, and match them reasonably. In addition, the quality of raw materials related to bronzing must also be guaranteed, such as the adaptability of hot stamping base materials, the performance of anodized materials, and the quality of hot stamping plates. If something goes wrong, it will definitely affect the final hot stamping effect. Equipment bronzing equipment: the choice of bronzing equipment is the key factor to determine the bronzing quality. Sheet-fed bronzing machine has three types: flat press, round press and round press. At present, the most widely used is the flat press. Three kinds of stamping machines have their own advantages and disadvantages. Rotary stamping realizes line pressure, and the total pressure is small. It can easily complete large-area hot stamping with relatively small pressure and run smoothly. Rotary pressing has high production efficiency and is suitable for bronzing large quantities of live parts. Because it is difficult to process the round surface of copper plate and the production cost is high, the heating roller is also more difficult than the plane heating. The flattening operation is flexible and convenient, which is more suitable for short version products. Compared with imported bronzing equipment, domestic bronzing equipment has obvious advantages in performance and price, but the overprinter accuracy, stability and function of imported machines are obviously better than domestic machines, and they are also more durable than domestic machines, which is more suitable for processing high-grade packaging products in fixed batches. The problem paste and anodized discolored paste after hot stamping are mainly caused by poor production of hot stamping plate, loose installation of anodized or incorrect anodized film. The discoloration of anodized aluminum after hot stamping is mainly caused by high hot stamping temperature. In addition, the wrinkling of anodized aluminum is easy to cause uneven stacking and discoloration of hot stamping, which can be solved by lowering the temperature appropriately. For the circular flattening machine, a fan can be installed at the foil feeding place to keep the foil floating, so as to prevent anodized from contacting the bronzing plate and burning before hot stamping. The surface gloss of anodized aluminum is damaged, and the outline of graphics and text is weak: for bronzing that needs film covering treatment, the gold foil is bronzed first and then coated for fear of being easily worn off. This is easy to cause the film layer (especially the matte film layer) to destroy the surface luster of anodized aluminum, and it is not suitable to use water-soluble glue to cover the film, otherwise it will cause the surface of anodized aluminum to be black, and it is easy to cause the gold powder to stick to the edge of the picture and text and cause weakness. After bronzing, it is depressed under pressure, and the glue is not easy to penetrate into the anodized surface, which is easy to cause the separation of 0PP from the paper at the bronzing place and affect the product quality. The correct process is to cover the film before bronzing, and choose anodized matching OPP. In a word, there are many factors that affect the quality of bronzing. Making high-quality bronzing plates and mastering bronzing suitability correctly are the keys to improve bronzing quality. The production of cigarette packets is different from other publications, which has its own unique printing processing requirements, high quality, decoration, anti-counterfeiting and other requirements, and it is printed in large quantities. Before production, enterprises should carefully read the construction sheet, do the daily maintenance of the machine, master the performance of electrochemical aluminum foil, and be familiar with the relationship between temperature, pressure and speed. Only in this way can the stamping quality of cigarette packets be guaranteed. Troubleshooting hot stamping is not up or not true: this is related to the surface characteristics of printed parts, the properties of anodized, hot stamping temperature and pressure. ① Excessive powder spraying on the surface of printed parts, wet ink or additives such as adhesive remover and varnish on the surface will hinder the adsorption of anodic alumina and paper. It can be used to remove powder from the surface of printed matter or dissolve it in the printing process. ② Improper selection of anodized will also directly affect the bronzing fastness. We should consider what type of anodized to choose according to the size of bronzing area and the characteristics of hot stamping materials. There are many models of anodized materials in the market, all of which have different substrates and the most suitable hot stamping range. They are mainly distinguished by the degree of adhesion and peeling during use. When the operator chooses anodized material with poor fastness and sealing for hot stamping, the hot stamping pattern on the cigarette case will appear false hot stamping and gold dropping. When selecting anodized aluminum, we can mainly refer to the following categories: 88-I type for common products, PM type for KURZ: 88-2 type for printed materials with strong ink colors such as cigarette packs and cosmetics (including printed gold and silver); Anodized materials such as 88-3, 88-4 and PM288 are used for fine stroke hot stamping of cigarette labels and cosmetic packaging, and 88-4, K series, LK series and SP series are used for UV ink hot stamping of paperboard and glazing paper. ③ The matching of bronzing equipment, hot stamping time and hot stamping temperature is incorrect, which affects the fastness of hot stamping and the clarity of graphic outline. Due to the different equipment and hot stamping materials, the hot stamping time and temperature are also different. For example, the high-speed rotary printing machine is fast, the nip contact, and the hot stamping temperature will be higher than that of circular flattening or flattening. In general, the temperature of circular pressing is 190% ~ 220℃, the temperature of circular flattening is about 130℃ ~ 150℃, and the flattening temperature is about 100℃ ~ 120℃. Of course, hot stamping time, hot stamping temperature and production efficiency are also largely restricted by the transfer performance of anodized. Also pay attention to check whether the pressure is balanced. If some pictures and texts are not hot-stamped, check whether the hot stamping plate is damaged. Reverse drawing: reverse drawing refers to drawing away ink or varnish after anodized hot stamping. The main reason is that the ink on the surface of printed matter is not dry or the UV post-treatment on the surface of printed matter is improper, which leads to the weak combination of ink and UV oil on the surface of printed matter and the paper surface. You should wait until the printed matter is dry before bronzing. In addition, anodic oxidation materials with low separation force and good thermal transfer performance can be selected.