Flexible packaging and flexo

One person in the industry said that flexographic printing has grown into an adult in foreign countries, and in China is still a baby. This metaphor is very appropriate! Indeed, China's flexo printing is still in its infancy, but she has shown a strong vitality. We believe: Flexo printing will be very useful in flexible packaging

1 Application status of flexo printing in flexible packaging

According to statistics from related departments, at present, there are nearly 240 production lines (including 170 import lines) for flexographic printing machines (including narrow-width and wide-width) imported from abroad by domestic packaging and printing companies and for domestically developed and developed narrow-width flexographic printing machines. 70 domestic lines). These production lines are distributed throughout the country, with more production lines in Shanghai, Beijing, Zhejiang, Guangdong, Shaanxi, and Yunnan. In China, 8 domestic printer manufacturing plants have begun to produce narrow-width unit type flexographic printing presses. In 2001, the output value of packaging printing in China was roughly 50 billion yuan. The market share of flexo printing has risen from 3% in previous years to 7%. According to the situation of China's printing industry equipment and the characteristics of flexographic printing, the development goal of flexo printing in 2010 was that the proportion of flexographic output in all package printing output values ​​rose to 15%.

In recent years, flexo printing has made progress in China mainly in the following aspects:

1) Flexo printing can basically meet the needs of packaging and printing. After many years of production practice, flexo has its own position in the packaging and printing market in China, and its market share is gradually increasing, but the proportion of plastic flexible packaging flexo printing using satellite flexo printing machines is still very small. In addition, companies in Shanghai, Beijing and some international multinational corporations have realized that flexo printing uses ink and ink printing, and the printed products are not polluted, which is conducive to health and environmental protection. The quality of products will win the recognition of customers. Therefore, like Nestle, Johnson & Johnson, and mystery Brand-name companies such as KFC have adopted flexo printing. Some procurement managers of foreign companies, for the consideration of flexo printing as green printing, must submit the orders to companies that have flexographic equipment. Facts have proved that the flexo process not only meets the needs of packaging in terms of quality, but also cooperates with mechanized packaging to increase production efficiency and reduce production costs.

2) In recent years, the quality of flexographic products in China has improved significantly.

3) Most companies have been able to master the flexographic process technology, and their operational proficiency is gradually improving. Flexo printing process and operation technology are completely different from gravure printing. Most flexible packaging manufacturers in China that previously used flexographic printing equipment used gravure printing equipment. Therefore, the characteristics of flexo printing were difficult to grasp in the initial stages of production of each factory, and they appeared in production. Some quality problems caused a lot of waste products.

4) Some companies have achieved better economic benefits. These flexo companies have one common feature: adequate living resources, stable product quality, high equipment utilization, and good economic returns. For example: Shandong Xinhua, Shanghai Printing Eight Factory, etc.

5) Domestic flexographic presses and supporting materials have been developed. Due to the rapid development of flexographic technology in China, it has led to the development and production of domestic equipment such as flexographic printing presses, anilox rollers, plates, and inks. So far, there are 10 domestic manufacturers that can produce flexo presses: Xi'an Black Bull, Shaanxi Beiren, Shanxi Taihang, and Shanghai Ziguang.

2 Advantages of Flexo Printing in Flexible Packaging

The difference between flexographic printing and other printing methods lies in its unique characteristics. First, the use of a soft polymer resin plate (such as the Cyrel plate produced by DuPont Co., Ltd.) reduces the cost of platemaking and shortens the platemaking cycle. , And due to the increase in the level of plate manufacturing and plate making technology, cable screen version can now reach the level of 175 lines, enough to meet the needs of general packaging and printing; Second, the use of anilox roller transfer ink, because the anilox roller is the transfer roller of the ink It is also an ink metering roller that realizes the same short ink path as the gravure printing, and can accurately supply the ink according to the process requirements. At present, the metal-ceramic anilox roller laser-engraved can reach the level of 1600 lines, for the precise control of ink color and The thickness of the ink layer provides a favorable means; Third, the small pressure printing, both to reduce the vibration and wear on the machine, but also reduces the wear on the plate, but also expand the scope of the print media, in particular, is conducive to the printing of flexible materials Fourth, in addition to printing, the narrow-format flexographic printing press can also complete a large number of post-press processing, making the flexographic printing press a production line integrating printing and post-press processing. Comparison between flexo and gravure is shown in Table 1.

The advantages of using flexible printing in flexible packaging mainly include:

1) The ink layer is thick and the ink is uniform.

2) Widely use non-toxic water-based ink printing. Flexo Ink is the only non-toxic ink approved by the US Food and Drug Association in all printing methods. As a result, flexographic printing is also known as green printing and is widely used in food and pharmaceutical packaging, which is not comparable to other printing methods such as gravure printing. The investment is significantly lower than the same size gravure press.

3) Wide range of printable media. The flexo printing machine can print paper, and can also print aluminum foil, plastic film, self-adhesive film, cellophane, etc. The types of substrates are more than gravure printing.

4) The equipment has a comprehensive processing capability. Almost all narrow-width unit type flexographic printing presses can perform post-printing processing on the same device, such as reverse printing, coating, laminating, die cutting, cross cutting, slitting, and punching.

5) Low production costs and high economic returns. Comparing with gravure printing, which is commonly used in flexible packaging, the plate making cycle is short and the plate making cost is low: less ink consumption than gravure printing; less power consumption; faster printing speed; the highest printing speed of the flexo printing machine can reach 600m/min; The rate is lower than the gravure printing; it occupies less production site; and the comprehensive processing ability is strong, and it can be formed at one time, which saves the labor of the subsequent process; and it avoids the waste of the turnover between processes, so the comprehensive production cost is low.

6) Under production investment. Because of the relatively simple structure of the flexographic printing press, the equipment investment is significantly lower than the same size gravure press.

In summary, most products printed by gravure printing can use flexographic printing, and can reach or approach the quality level of gravure printing. On the other hand, some of the products printed by flexographic printing machines cannot be printed by gravure printing. In terms of cost of use, the flexographic printing method is much lower than the gravure printing method. Undoubtedly, the use of flexible printing for flexible packaging printing production is a wise choice for low input and high output.

3 The “bottleneck” encountered by flexo printing in the flexible packaging industry

In previous years, there were two very extreme views. A: The flexographic version is so good that it will replace the gravure in the future and it will even replace offset printing. Second: The flexographic version is too bad to print only a very small product. Both of these arguments are biased. In order for China's flexo printing to achieve a healthy and rapid development in the flexible packaging industry, we must solve the following problems in the development of flexographic and gravure printing from the understanding and practice.

1) Insufficient living resources of some companies

Flexo printing is suitable for batch production and continuous production of printed products. If the amount of printing is small, the quality of printing is not stable, which will lead to increased costs and waste. At present, there are still some flexible packaging companies engaged in flexo printing production in China. Due to insufficient living resources, insufficient production tasks, and inefficient use of equipment, they are underemployed and “wait for the rice”.

2) Unreasonable equipment selection

In the introduction of flexo printing equipment, the first consideration should be given to the objects to be printed by the flexo printer, and the structure and performance of the flexo printer should be fully understood to ensure that the equipment configuration is reasonable and meets the flexo printing requirements. In the previous period, some companies only considered the price factor when choosing a flexographic printer, and ignored the rationality of the configuration. As a result, due to incomplete configuration, some printed products could not be printed.

3) Poor supply channels for auxiliary materials

Most of China's flexographic printing auxiliary materials (except ink and wash) are imported from abroad, such as plates, double-sided adhesives, squeegees, etc., not only are expensive, but also have a long supply period, fewer domestic sales agents, and incomplete varieties of specifications. There is no room for the user to choose. This is the key to the development of flexo printing. The types of domestically-made flexo inks are relatively complete. There are both ink and ink suitable for various types of printing materials, and the latest anti-counterfeiting inks, which should be said to have developed rapidly. The requirements for fineness, fluidity, viscosity, and other properties of inks and inks vary with different substrates. Therefore, the development of corresponding inks for specific printing materials and different printing processes is to improve the quality of flexographic products, reduce the rate of rejects, and broaden flexo printing. The important way of the market. At present, high-quality fine-water gold and silver inks and uv inks are almost dependent on imports, and the prices are high.

4) Flexo printing process is not well understood

Most flexible packaging companies are familiar with the gravure process, but are unfamiliar with the flexo process. After introducing the flexo printing process, the internal structure and management of the enterprise must be adjusted accordingly. The common faults of flexo printing are poor ink, dry printing, stencil printing, edge defects, improper pressure, graphic deformation, and dimensional displacement. To solve these problems, in addition to the equipment and material factors, attention must be paid to the anilox roller. The relationship between the matching, the pressure of the anilox roll and the printing plate, the pressure of the printing plate and the impression cylinder, the viscosity of the ink and the speed of the machine, etc., it is difficult to print a good product without a set of data and operating procedures. The current flexo printing industry should not only have its own printing experts, but also experts in platemaking and ink painting.

5) Problem of flexo platemaking process

The flexographic version is mainly divided into two categories: base and non-base. The thickness of the base material plate is about 0.95ram, and the thickness of the non-base material plate is 1.7ram, 2.28ram, 3.94mm, 7ram, and the like, respectively. At the time of plate making, back exposure is performed first, and then main exposure is performed. The length of the exposure time varies depending on the pattern level and the climate. The unsensitized part of the photoreceptor can be removed by rinsing and then dried by de-bonding. A piece of printing plate can be taken with lJ in only 2 hours. The recent use of flexo CTP tapes with the 1J version enables high-quality, high-efficiency digital imaging and direct printing (see Printworld 2004, Issue 3).

6) Technical training issues

The technology, processes, equipment, and equipment of the flexographic printing are a whole and they are closely related to each other. At present, some flexible packaging flexographic equipment is not functioning properly and product quality is not stable. Except for insufficient living resources and unreasonable supporting factors, one of the most important reasons is the flexographic printing from product design, plate making, printing to postpress processing. The entire process is not yet fully understood. Therefore, flexo companies should strengthen technical training.

4 Conclusion

Soft packaging is one of the main branches of packaging, and it is also the industry that has the most disputes in terms of flexo and intaglio in the world and the greatest difference in development. In this area, the United States uses about 70% to 80% of the flexographic printing, Europeans 35% to 40%, and Asia (including Japan and South Korea) accounts for 8% to 15%. The proportion is lower. The biggest problem in the promotion of flexographic technology in our country is in the field of flexible packaging.

From this, we come to the following conclusions:

1) To see the relationship between flexographic and gravure printing differently, the comparison between flexo and gravure is relative. In the field of flexible packaging, it is still gravure to dominate the world. But in the future, flexographic printing methods with many advantages will surely make great strides.

2) Flexo and gravure are in the areas of comparison or competition, mainly coexistence and complementarity, not the relationship of "who replaces who?" Flexo and gravure are constantly improving technology and overcoming their own deficiencies. The development of flexo printing in the field of flexible packaging is a longer-term process.

3) The market share of flexo and gravure varies from country to country. The core driving force for the development of these two technologies is the market. Flexo has a good future for development in China.