Application of the hottest pad printing on plastic

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The application of pad printing on plastic bottle caps

bottle caps have two types: one is plug-in, the other is circular rotary. The plug-in bottle cap generally does not need to be installed repeatedly, and its shape is relatively complex. It mainly completes some functional actions, such as spray. At present, it is mainly used in plastic bottle packaging of some shower gels, hair care products and pesticides. Circular rotating bottle caps are common and widely used. In addition to protecting the products in the bottle from the impact of the environment, this kind of bottle cap also plays the function of transmitting some important information (such as products with exquisite workmanship). For example, vertical bags with the shape of nearly subtracting two curved spaces are no longer popular, such as the plastic bottle caps of tea drinks of uni President Group and Baudelaire packaging products. Therefore, the decoration of the bottle cap cannot be underestimated. This paper discusses the printing of words or trademarks on the surface of rotating bottle caps. Pad printing is the preferred printing method for plastic bottle caps. When customers receive orders for bottle cap printing, the first thing they think of is the pad printing process. Pad printing technology is a unique printing method developed with the silk printing technology, which is similar to the rubber stamp in our daily life. Pad printing adopts the relatively independent position relationship between the printing plate and the substrate. No matter how strange the shape of the substrate is, it can complete the task excellently. This makes the so-called "universal printing" printing difficult to complete many tasks, and finally chose the pad printing process. Its production capacity and equipment are small. Printing plastic bottle caps by pad printing process has several advantages that other printing processes cannot. (1) It is convenient to change varieties and simple to make plates. (2) Less investment. Compared with other printing equipment, pad printing equipment has the least investment. (3) Strong adaptability. The shape of pad printing rubber head can be changed at will, which greatly enhances the adaptability of pad printing technology to the shape of substrate, and is suitable for bottle cap printing with different appearance and size. According to our investigation, the diameter of about 80% of bottle caps will not be greater than 40mm. That is to say, the area of a steel plate is 100mm × 100mm pad printing machine can complete the printing of bottle caps with moisture absorption rate of 8% - 12% and about 80%. Elements of pad printing of plastic bottle caps

1 Ink in plastic bottle cap pad printing, the choice of ink is very important. The bottle caps are basically made of PP and PE materials, and the selected ink must match the type of printing material. When selecting ink, the following two points should be paid attention to. (1) Some inks are added with hardener, which improves the adhesion effect, but increases the difficulty of operation. Therefore, unless the customer has special requirements, it is recommended not to use this method. (2) It is better to choose pad printing ink rather than printing ink. Printing ink has better leveling property, while pad printing ink has better colloidal property; The drying speed of printing ink is relatively slow, and the drying speed of pad printing ink is faster. Although solvent ink can be used for pad printing, its effect is not as good as special pad printing ink. If you need to use UV ink, you should not choose UV printing ink, because the transferability of UV printing ink is too poor. If UV printing ink must be used, a certain amount of gelatinizer should be added to it. 2. At present, the selection of rubber head is generally ignored in China, but in pad printing, the selection of rubber head should be very strict. In bottle cap pad printing, circular rubber head is widely used. When selecting the rubber head, you need to pay attention to the following two points. (1) In the printing process of eye tone image, the hardness and shape of the rubber head selected for yellow, magenta and cyan should be exactly the same, and the hardness of the rubber head selected for black can be slightly higher. (2) Choose a rubber head with good film removal performance, which draws on the essence of some formulas of offset blanket, and can improve the printing quality of PP and PE surfaces. 3. For bottle cap manufacturers who attach importance to pad printing quality, resin intaglio is a wise choice. This kind of printing plate is made of nylon polymer, which does not need corrosion process and is conducive to quality management. At present, resin gravure is widely used in pad printing machines produced in Europe and America. 4. Cost the printing area of bottle cap is very small, so some people think that there is no need to worry about its cost. However, with the intensification of market competition, we should pay attention to reducing costs. This is why many manufacturers use pad printing instead of flexographic printing when printing bottle caps. At present, the price of the cheapest monochrome pad printing machine is about 10000 yuan, including steel plate, fixture and rubber head. With this configuration, the cost of monochrome printing of bottle caps is generally not higher than 1 cent. If the full-automatic pad printing machine is used, the printing volume is less than 500000, and the cost is roughly the same. If the printing volume exceeds 500000, the cost will be reduced

development trend of pad printing of plastic bottle caps

1 Online production at present, in the domestic market, the most commonly used model is the single machine operated pad printing machine. The operator must place the products one by one, and then remove them after printing, so the production efficiency is extremely low. The full-automatic bottle cap pad printing machine integrates flame treatment, pad printing and drying, and has the functions of automatic feeding and unloading. It is mainly used in the production of bottle caps in large enterprises, which can greatly improve the production efficiency. If it is connected with the bottle cap production line, the production efficiency will be higher. The specific process of the on-line production of the full-automatic bottle cap pad printing machine and the bottle cap production line is as follows: after the bottle cap transmitted from the bottle cap production line arrives at the pad printing machine, the sensor detects the existence of the bottle cap and sends out instructions, the flame treatment device automatically ignites, carries out surface treatment on the bottle cap, then the bottle cap enters the printing station for printing, carries out drying treatment after printing, and the dried bottle cap is automatically sent to the conveyor belt. 2. Multi color printing with the improvement of people's requirements for added value of products, more and more multi-color printing is used for bottle cap decoration. One method is to use multiple monochrome pad printing machines to connect production, one machine printing one color, through color superposition to achieve. Although this process takes up more manpower when using logic pen and oscilloscope to detect signals, its overprint accuracy is higher than that of domestic rotary disc multicolor pad printing machine. Another method is to use multi-color pad printing machine. This method will undoubtedly improve the production efficiency, because a machine only needs one person to operate, and many bottle caps can be placed at one time. However, according to the samples printed by most manufacturers at present, the overprint accuracy of multi-color pad printing machine is still not very ideal, which is related to the manufacturing accuracy of multi-color pad printing machine itself. Pad printing in Europe and the United States, UV pad printing process has entered a mature period, but in China is basically still blank. UV pad printing process of bottle cap has many advantages: first of all, UV ink has strong resistance to repeated use, and the printed graphics and texts on the bottle cap will not be eroded by sweat and grease on the fingers. Secondly, UV ink basically will not have a negative impact on the environment and operators. At present, printing bottle caps with UV pad printing ink faces two major problems. One is the poor adhesion of the ink, which is not as good as solvent based ink. In Europe, Marabu TPC UV pad printing ink is the first, but this kind of ink is rare in the domestic market. Second, the high cost of UV ink will increase the cost of bottle cap decoration printing, which is not conducive to its promotion

reprinted from: Printing Technology

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