Label printing and ink (on)

Abstract: This article describes the market development of label printing, and gives a brief overview of the printing performance of various labels and the corresponding inks. Focuses on the in-depth exploration of UV inks used in adhesive products.

Keywords: Label Printing, Stickers, UV Ink

Labels can be said to be a bright spot in the printing industry in recent years. In particular, self-adhesive labels have formed a complete industrial chain in China, and the position of label printing in the market has gradually been valued by people.

For now, the biggest problem with label printing is the small-lot demand for label printing, the trend of multiple varieties, and environmental protection issues. In fact, these problems have not only occurred in the label printing industry, but also a common topic facing the printing industry. However, the label industry must respond accordingly. Some printing companies have proposed the following solutions for the requirements of small batches and multiple varieties: the introduction of printing machines that are easy to change versions; and the establishment of an in-plant management system from order receipt, printing to delivery. The introduction of computer control equipment in the pre-press and post-printing process is a proper method for adjusting the time.

First, the status of the label printing market

According to many printing industry insiders, at present, the domestic label market has the following characteristics: Paper labels are still the mainstream of labels, but the growth of film labels is very rapid. For example, mid- to high-end day-to-day products use film labels. The reason is that Film labels have excellent water and moisture resistance, high temperature resistance, abrasion resistance, and tear resistance.

In contrast, shrink labels have the fastest growth among various types of labels. The materials and forms used in the labels have also become increasingly diversified, and more and more label products have been printed in a roll. The application of flexographic printing technology has gradually increased, and many flexographic printing presses have adopted combination printing methods to install rotary screen printing units, hot stamping or cold stamping units. Small batch orders, quick change jobs, and fast delivery have become the main requirements for end users. As a high-tech new product, RFID tags have functions such as product tracking and control, which also indicates that the label printing has entered the digital printing field.

The main label types and application areas, we can refer to the following table. A brief overview of the current mainstream labels on the market will follow.

1, stickers.

Self-adhesive labels, also called self-adhesive labels, timely stickers, sticky notes, etc., are composite materials made of paper, film or special materials, coated with adhesive on the back, and coated with silicon protective paper as the backing paper. After printing and die-cutting, it becomes a finished product label. The application requires only peeling from the bottom paper, and can be applied to the surface of various substrates with a single press, and labeling machines can also be used to automatically label the product on the production line.

In China's label market, self-adhesive labels occupy a dominant position, and its annual growth rate is about 20%. However, compared with developed countries, there are still many opportunities for growth and development. Our self-adhesive label industry has its own characteristics, that is, there are many small and medium-sized factories and specialized large-scale printing factories; there are many primary equipments in printing factories and there are few high-end equipments; the development of sticker market is unbalanced, and the coastal areas are developed. The area is developing and backward areas are relatively backward.

2, shrink labels.

The shrink label market is experiencing rapid growth and its market share continues to expand, far exceeding the annual growth rate of the general label market. The main application area of ​​shrink labels is the beverage industry. In addition, the growth momentum in the food, health care and personal care products industries is also very strong. The adaptability of shrink labels is very strong and can be used on plastic, wood, paper, metal, glass, ceramics and other packaging containers.

The commonly used film materials for shrink labels are mainly PVC, PE, PET, OPP, etc. They have their own characteristics in terms of shrinkage characteristics, environmental protection, etc., and they must be comprehensively considered when selecting a product. For example, PET materials are environmentally friendly and play an important role in the European market where recycling is highly valued. From the point of view of the printing process, the shrink label is still mainly gravure printing, and the market share of flexographic printing is relatively small. In addition, offset printing and digital printing also have a range of applications to meet the specific needs of customers.

3, in-mold label.

The structure of the in-mold label is different from that of the commonly used adhesive label, and its back surface has a layer of solid adhesive, and the adhesive melts at a certain temperature and sticks together with the surface of the container to be attached. The in-mold label was first used in injection-molded containers and later developed into blow-molded containers. It is widely used in packaging of various plastic materials such as HDPE, PP, and PET.

In North America, in-mold labels are mainly used for blow-molded containers. In Europe, they are mostly used for injection-molded containers. The proportion of in-mold labels used in container labels is 12% to 15%, and they are mainly used in care products, daily chemicals, and cosmetics. Food, beverages, lubricants, pharmaceuticals and other industries. In China, the introduction of in-mold labels into large-scale development is a matter of recent years, but the development rate is quite alarming. Currently, it is mainly concentrated in the lubricants and daily chemical industries.

4, RFID tags.

RFID tags are developed on the basis of electronic technology. It has a huge amount of information stored, and it is flexible and non-contact reading and writing, and has a strong adaptability to the environment. According to the professional analysis and forecast of the global RFID tag application market, by 2009, the global RFID market will increase from 2 billion U.S. dollars in 2003 to 10 billion U.S. dollars.

At the same time, the field of application of RFID tags continues to expand, rapidly infiltrating into various fields. RFID tags in the logistics and warehousing, manufacturing, commercial retail, commodity anti-counterfeiting, transportation, military and other fields of national defense and other fields of experimental and practical applications are gradually starting. If RFID technology can be closely linked with the electronic supply chain, it is likely to replace the bar code scanning technology. In the long run, beyond the logistics field, for example, product-level RFID tags can be used for anti-counterfeiting of medical supplies, air baggage, and library management.

The RFID tag market in China started relatively late and there is a considerable gap between the application and foreign countries. The most direct issue of RFID tag frequency has been basically determined in many parts of the country, but China has not yet approved it. Moreover, there are many problems in the domestic market, such as weak basic R&D strength, insufficient participation in standardization, and a mostly wait-and-see attitude among domestic companies.

Currently, there are three major obstacles to the entire RFID technology: standard barriers, cost barriers, and technical barriers. The standard barrier refers to the need to apply RFID, it must develop a unified, open technical standards, but at the same time there are multiple standards on the market, and many other countries and regions are developing appropriate standards for themselves; cost barriers refer to The application field has always been very sensitive to the increase in cost. How to promote the application, the cost can also be said to be the dominant factor; technical barriers, such as the readability of RFID tags, model matching, and data processing, are thorny issues that need to be solved.

4, digital labels.

In the past few years, the label market has undergone significant changes. Markets and consumers need smaller batches of products, shorter delivery times, and greater personalization. Traditional printing is difficult to meet this demand in terms of time and cost. As a complement to traditional printing methods, digital printing has higher flexibility and better cost-effectiveness. It can also realize variable data printing and printed labels. Batch backlogs in warehouses no longer occur. Moreover, with the gradual improvement of the performance of digital printing presses, the range of printing materials used has become increasingly widespread, and digital printing has also been applied more and more in the field of packaging and printing. Digital printing technology first entered the field of packaging and printing is for variable data printing and short-run label printing.

The digital labeling solution with variable data printing capabilities enables label printing companies to quickly provide short-run labels at low cost, achieve a long-term balance, and provide print customers with a low-cost solution for printing. Satisfy the customer's multi-faceted needs, personalized printing to meet the user's needs for product segmentation in the market, anti-counterfeit printing capabilities to provide customers with a more secure full-service, and further enhance the company's market competitiveness.

Second, the choice of label ink

There are many types of label printing inks, which can be divided into three categories based on the solvents used: water-based label printing inks, solvent-based label printing inks, and UV label printing inks.

Water-based ink is safe, sanitary, non-polluting, conforms to environmental protection requirements, and is beneficial to human health. However, it also has disadvantages, such as slow drying speed, low color saturation, poor stability, etc. It is not suitable to print large areas on the ground. It is prone to precipitation and separation for a long time. Layer phenomenon.

Solvent label printing inks have strong adaptability to label materials, stable performance, and high printing quality; however, there are environmental pollution problems and some volatile solvents are harmful to the human body.

UV label printing ink has good performance, reliable quality and wide application range; but the price is high, and it requires special drying equipment, and it also has certain requirements for supporting materials.

When choosing the label printing ink, it is necessary to comprehensively consider the types of printing materials, printing methods and printing conditions, customer's special requirements, post-press processing technology, the use of the label and the conditions of use, cost and other factors. The properties of label printing inks mainly include hue, fineness, saturation, glossiness, adhesion, viscosity, and drying properties. These properties have an important influence on the printing process and print quality.

Third, adhesive printing process

Flexographic printing is a new type of printing technology that is currently popularized in the international printing industry. The advantages are that the machine structure is simple, the cost is low, the printing quality is comparable to that of gravure printing, and the ink layer does not have the advantages of thicker ink layers. Its ink uses water-based ink, does not pollute the environment. Some developed countries’ legislation requires the use of flexible printing for packaging labels used for food and medicine.

Nowadays, the flexographic printing plates are mostly made of solid resin plates, and the inks use universal ink or UV ink. Although the soft version has the advantage of full ink, but the print cable is limited, generally only reach 133 lines / inch, far from meeting the adhesive label users higher and higher quality requirements.

Flexo label printing equipment is all narrow flexographic printing machines, mainly domestically produced, equipment has two characteristics: one is to use UV ink instead of water-based ink. The UV ink has good stability and avoids frequent cleaning of printing plates and inking systems. What is more important is that the color density of the UV ink is greater than that of the water-based ink, which can improve the printing quality of the label. Another feature is the universal use of filmless direct laser platemaking technology, which avoids the loss of small dots, the parallelization of large dots, and the improvement of image layers. The sharpness of text and graphics and the quality of printing are greatly improved.

Flexographic printing, with its high-quality printing products, and the uniqueness of the so-called "green printing", will become the trend for future label printing. Therefore, it is no exaggeration to say that the flexographic printing sticker is the future direction of development. At present, flexographic printing equipment produced by domestic enterprises using domestic resources and foreign technologies is gradually being printed by domestic printing companies in terms of printing quality and price. Accepted, the market share of application of flexographic printing stickers is growing rapidly