Merck is the world's leading manufacturer and supplier of pearlescent pigments. It has accumulated rich experience in pearlescent printing and made active efforts to improve the adaptability of pearlescent pigments to various printing methods, ensuring the reproduction of pearlescent effects from the source. According to Mr. Yan Xin of German Merck China Co., Ltd., technically speaking, pearlescent effect can be achieved through all commonly used printing methods, such as printing, gravure printing, offset printing and flexographic printing. However, the application scope and market share of various printing methods are uneven, and various printing methods also show a trend of change in pearlescent effect reproduction
the particle size of pearlescent pigment is relatively large, and silk printing has a very wide range of adaptability to ink particle size, so it is very suitable to reproduce the pearlescent effect by printing. At the same time, printing can also produce many other special effects, which are deeply favored by packaging users
but in terms of ink drying speed, the working efficiency of pearlescent printing is relatively low, which is not suitable for mass printing. If UV ink is used instead of ordinary ink, although the curing speed can be improved, the high reflectivity of its printing surface has a great negative impact on the expression of the texture of some pearlescent pigments, so attention should be paid to the selection of pearlescent pigments
pearlescent gravure printing
in the field of packaging printing, gravure printing can print spot colors with thick ink, and it is not a problem for pearlescent printing with special effects. Compared with other printing methods, pearlescent gravure printing has been widely used due to its technological maturity. However, the high cost of gravure plate making limits its application in small batch products. How to effectively reduce the production cost is the key problem to be solved in Pearl gravure printing
pearlescent offset printing
offset printing has the advantages of convenient plate making and low cost. Many packaging and printing plants like to use offset proofing when trying new packaging products, especially pearlescent products
however, few users actually use offset printing for pearlescent printing. The reason lies in the thin ink layer and long ink path of offset printing, which are not suitable for the transfer of relatively large particle size and fragile pearlescent pigments, and there are certain difficulties in the dispersion of pigments. These problems often perplex packaging and printing manufacturers, so that Pearl offset printing can not achieve mass production. Therefore, further reducing the particle size of pearlescent pigments and enhancing the wear resistance of pearlescent pigments are the product development direction of pearlescent pigment suppliers
pearlescent flexographic printing
in the field of pearlescent printing, it can be said that gravure printing and printing have little room for development due to the maturity of technology. In recent years, flexographic printing technology has made great progress, and it plays an increasingly important role in pearlescent printing. For example, arranging pearlescent inks in different flexographic printing units according to different color sequences, or using pearlescent pigments with different particle sizes, can reproduce rich effects
at present, the production cost of supporting materials for flexographic printing, such as printing plate and embossing roller, is high, which is the main factor hindering the development of pearlescent flexographic printing. In addition, the uneven quality of inks and the limited operation level of employees will also lead to the unsatisfactory quality of pearlescent flexographic prints
in the interview, Mr. Yan Xin also conveyed another idea to us, that is, pearlescent printing is no longer used alone, but combined with other printing methods or other surface finishing methods to reproduce distinctive effects. For example, new flame-retardant materials make the interior of the cabin ignite more slowly. At drupa 2004 exhibition, some offset printing machine manufacturers launched multi-color offset printing online glazing equipment. The glazing unit adopts flexographic printing method, and the ink is transferred by laser ceramic roller, which greatly optimizes the operating difficulties of pearlescent pigment particle transmission enterprises and increases the reliability of delivery. Moreover, the connection with offset printing process fully improves the flexibility of printed matter decoration. In addition, sheet fed gravure printing combined with offset printing or hot stamping on pearlescent ink layer has also been well used
as a supplier of pearlescent pigments, Mr. Yan believes that the application of new technologies and equipment is very important in the pearlescent printing field, which is self-evident. For example, the emergence of the glazing unit that adopts the ink transfer roller enables the special gloss effect to calmly cooperate with offset printing products; The new Praxair art hole can help the fine printing of coarse-grained pearlescent pigments
users experience that printing methods have their own advantages and disadvantages
in the interview with Mr. Yan Xin, we learned that at present, various main printing methods have been involved in the reproduction of pearlescent effect, and pearlescent printing has become a must for strategists. But how about the actual application? Now let's learn about it through specific cases
case 1: Henan Golden Mango Printing Co., Ltd.
Henan Golden Mango Printing Co., Ltd. used gravure printing to finish the cigarette label with pearlescent effect. According to Mr. Tang Qingchao, the cigarette label box and small box products printed by Golden Mango company with pearlescent ink mainly include Shahe (pearlescent) small box, Golden Mango (pearlescent) small box and Luoyan (pearlescent) small box. The surface of these cigarette labels printed by pearlescent printing has pearl like luster or metal like luster, which especially attracts the attention of the public
Mr. Tang Qingchao still remembers the original intention of using pearl ink printing, He said: "At that time, the competition in the cigarette label printing market was quite fierce, and we couldn't attract customers without special surface finishing effect. On the one hand, pearlescent ink was non-toxic and free of heavy metals. On the other hand, it could also improve the grade and ornamental of cigarette packaging and increase the added value of products, so our company decided to introduce pearlescent printing. After introducing pearlescent printing, our company received a considerable number of orders, which greatly increased the economic efficiency." Benefits "
however, it is not as simple as expected to carry out pearl gravure printing, and there are still some problems in production. Mr. Tang summarized and analyzed some common problems in production
first, pearlescent powder is easy to precipitate. The size of pearlescent powder that can be soaked in solvent for a long time (at least 3 hours) should be used later according to the shape and foundation drawing rules. The pearlescent ink in the ink bucket should be frequently stirred during the printing process
second, pinholes and small bubbles appear on the surface of printed matter. There are two main reasons for this phenomenon: on the one hand, there is water or particles in the diluent, and on the other hand, there is diluent powder mass when the diluent is mixed with pearl polishing powder. This kind of powder mass will break and fall off after the printing ink layer is dried, forming a small pinhole phenomenon. When the above problems occur, they can be checked according to the actual situation
third, stripes appear on the surface of printed matter, especially when printing large-area pearlescent effect, which is manifested in longitudinal stripes on the surface of printed matter. This is due to the low viscosity of pearlescent ink and uneven mixing of pearlescent powder and ink. In view of this situation, it is necessary to reduce the amount of solvent added in the ink or select a plate cylinder with an appropriate depth of shape carving or diamond carving when the machine is normally turned on, and the doctor blade should be checked frequently and replaced in time. In addition, blocking is one of the common faults in gravure printing, and it is no exception when printing pearlescent ink. For this, pearlescent powder with appropriate particle size should be selected; Reduce the oven temperature or increase the printing speed
even if there are problems, Golden Mango company still tasted the benefits of pearlescent printing, and they are more enthusiastic about pearlescent printing. Mr. Tang said that in the future, on the one hand, the company should print corresponding products with pearlescent ink according to the requirements of customers; On the other hand, they will independently design high-end products printed with pearlescent ink and recommend them to customers; At the same time, they will pay close attention to the new technology of pearlescent printing and apply it to product design and production in time
case 2: Yunnan Wanhong Color Printing Co., Ltd.
the "Redwood" and blue "Dongdu" of Jiangsu Xuzhou cigarette factory are the main products of Yunnan Wanhong Color Printing Co., Ltd. According to Mr. jiangzhihui of the company, at that time, Xuzhou cigarette factory launched the new product blue "Dongdu". In order to improve the market competitiveness of blue "Dongdu" products, Xuzhou cigarette factory requires that pearlescent ink must be used for printing, which not only looks beautiful, but also increases the anti-counterfeiting performance of cigarette labels. In order to meet the requirements of customers, Wanhong decided to use a flexographic printing machine to print pearlescent ink after investigating the market. The result, of course, is to improve the added value of the product and the role of the flexographic printing machine as desired by customers
for pearlescent flexographic printing, Mr. Jiang commented, "The use of flexible printing pearlescent ink can obtain a good pearlescent effect, increase the texture of cigarette labels, and the flexible printing has a wide range of adaptability to the granularity of pearlescent pigments. Through the organic combination of the careful design of the company's designers and the sense of printing quality, a new color space can be reconstructed on the surface of plain and plain paper, film and other substrates, so that the packaging products show a special pearlescent effect". However, in order to obtain the desired effect, we must select the appropriate corrugation roller and ink, and carefully adjust it according to the printing substrate and printing speed in the printing process, so as to control the viscosity and drying speed of pearlescent ink. Mr. Jiang believes that under normal circumstances, it is appropriate to control the ink viscosity at 50 ~ 60s (4 chaen cup, 25 ℃); When printing coated paper and film, the appropriate viscosity is 20 ~ 30s (4 chaen cup, 25 ℃), and the printing speed is 120m/min. The slower the printing speed is, the higher the ink viscosity should be
after the pearlescent printing of blue "Dongdu" cigarette label with flexible edition, the technicians of Wanhong company did not stop the pace of development. They also boldly used offset printing machines to catch up with the blue "Dongdu" flexographic pearlescent printing samples, but the effect was always bad
in this regard, Mr. Jiang believes that offset printing is less mature than gravure printing and flexographic printing in terms of pearlescent printing, because the viscosity of offset printing ink is relatively high, and pearlescent pigment is particles ground out of shells, which is difficult to dissolve, resulting in pearlescent pigment and offset printing ink difficult to mix, even if mixed together, the distribution of pearlescent pigment is uneven. As we all know, the pearlescent effect of printed matter is directly related to the particle size of pearlescent pigment. The larger the particle size of pearlescent pigment is, the more obvious the pearlescent effect is. 1. How to solve the problem of sensor displacement by electronic universal experimental machine is, which also means a greater challenge for offset printing
in addition, Mr. Jiang also compared the cost of pearlescent offset printing with that of pearlescent flexographic printing. Mr. Jiang holds different views on people's view that the cost of pearlescent offset printing is low. He said, "UV ink is used for offset printing pearlescent ink, and the price is high. 1kg costs about 200 yuan, which is not cheaper than flexible water-based ink; although the plate making of pearlescent offset printing is cheap, the flexible version used by our company is made by our own company, and it is not very expensive. Of course, except for making laser version outside"
as for the later introduction of gravure printing equipment for pearlescent printing, it is because the "Redwood" cigarette label has further requirements for the fineness of pearlescent effect
case 3: Zhejiang Meinong silk printing Co., Ltd
Copyright © 2011 JIN SHI