In-mold labeling of next-generation label application technology

Although the application of in-mold labels in China is still in its infancy, with its many advantages, in-mold labels will surely continue to increase market share in the next few years.

Last few years. The widespread use of labels and the ever-increasing variety have driven the development of label printing technology. Compared with heat shrinkable labels, direct screen printed labels, and adhesive labels (mainly self-adhesive labels) produced by the traditional label printing industry. As an emerging label printing technology, in-mold labeling has gradually been promoted and applied in China in recent years. In-mold labeling is a new form of label packaging that differs from traditional labels. It has been popular in some countries in Europe and America for more than 20 years. Mainly used in cosmetics, cosmetic products, pharmaceutical industry, lubricants industry. Its production process is processed with PP or PE synthetic paper on the surface. The back is coated with special hot-melt adhesives for processing into special labels. Printed into a trademark. Although the application of in-mold labels in China is still in its infancy, it has many advantages. In-mold labels will certainly continue to increase market share in the coming years.

Printing materials determine their market potential

The core of an in-mold label is the material itself, not the printing process, which is the difference between it and other labels. In addition to the printability of the printing press, the in-mold label material must also have characteristics of use. Therefore, in-mold labels have many differences in the formulation and structure of materials from ordinary label materials.

At present, the commonly used substrates in the market generally include PP, PE PP/PE compound, PP plus coating. There are also BOPP and paper substrates. However, the application is still relatively small. From the characteristics of the substrate, PE is the most flexible. PP/PE Secondly, PP has the most stiffness. The above mentioned materials. In addition to paper, it has certain waterproof, anti-oil and anti-acid properties. It can be seen that the breadth and versatility of in-mold label materials determine the prospects of their market applications. Label materials are basically divided into two categories according to their physical characteristics. That is, paper and film. Paper materials will be deformed due to water or moisture. Causes the ink to fall off, the strength decreases, affect the use effect, and the bottle (bucket) must be removed when the label is removed. Inconvenience to the reuse of packaging. and so. In developed countries, paper in-mold labels are gradually being replaced by thin film materials. In my country. In-mold labels have only just started, drawing on foreign experience. All plastic film materials are used.

In the process of using film materials. Although their production process is different. However, the basic structure of the material is the same, that is, it is composed of a printing layer, a middle layer, and a binder layer. The printing layer accepts the ink to form a graphic: the middle layer plays a supporting role to make the material have sufficient strength, does not deform under the effect of the printing tension and high temperature, ensures overprinting accuracy, and can have good transparency or opacity as required; The agent layer is the key to guarantee the use effect of the label. This layer can be melted under high temperature. The label is integrated with the wall of the package (bucket). In order to make the printing layer has good ink repellency, the surface coating or corona coating method is used to improve the surface adsorption performance. And require a smooth surface, no wrinkles, no bubbles.

In-mold label printing process

At present, the in-mold label adopts the traditional printing method. The surface is coated with a layer of UV or EB curing varnish for protection. The back of the label is coated with a solid chemical adhesive. According to the characteristics of the in-mold label material, it is suitable for a variety of printing processes and different inks. Including: screen printing, uV letterpress printing, flexo printing, gravure printing and lithographic offset printing. When printing, use a robot to suck up the printed label and place it in the mold. The vacuum hole on the mold will hold the label firmly in the mold. When the raw material of the plastic bottle is heated and hangs in a hose-like form, the labeled mold quickly closes. Air is blown into the hose so that it fits snugly against the mold wall. At this time, the temperature in the entire mold is still relatively high, and the label-shaped solid adhesive adhered to the preform of the bottle body starts to melt and is combined with the plastic bottle body in the mold. When the mold is opened again, the plastic bottle body is molded, and the label and the bottle body are integrated into one, so that the finely-printed brand is firmly embedded on the surface of the plastic product. The label and the plastic bottle are on the same surface, and there is no label on the surface. Graphic text is printed directly on the surface of the bottle body.

There are two types of printing methods for in-mold labeling: web printing and sheet-fed printing. Different printing methods have different process characteristics. The former can be divided into on-line processing and extension multiple processing and the processing method is related to the factory's own equipment and label design requirements. If the printing process is carried out with a foil stamping label and the press has a round stamping stamping and die cutting device, the processed label can be formed at one time. If there is only a separate stamping and stamping machine, the label can only be processed multiple times. carry out. It is characterized by high production speed and high efficiency, but due to the high cost of the rollers, it is more suitable for mass production. The sheetfed printing process is mostly used for screen printing and offset printing. This is accomplished by multiple processes on multiple machines. The printing process is related to the process design. The processing is more flexible and the plate making cost is lower than that of the reeling mode. It is suitable for small batch production. , The printing effect is good, the screen printing field and offset printing are all better than the web printing.

In order to improve some of the utility or appearance effects of in-mold labels, post-process processing is also critical. According to the customer's requirements, it is necessary to carry out glazing, bronzing and other work to enhance the application performance of the label. Glazing can increase the glossiness of the in-mold label and the surface decorative features of the product. At the same time, in order to improve the wear resistance and high temperature resistance of the in-mold label. Hot foil stamping can use cold stamping and hot stamping techniques. Cold stamping foil is mainly used for flexographic printing. The use of cold stamping foil to obtain better visual effects requires higher processing technology. Generally, cold stamping is used to print after printing. A thick layer of ink covers the edges of the cold stamp. If the customer can accept the visual effects of cold ironing, this technique is recommended.

Create Productivity with Quality

The quality of products is undoubtedly the cornerstone of the company's development. Controlling product quality can continuously create new market miracles. For in-mold label printing, the influencing factors mainly include white spots, dirty spots, deformation of materials in the printing process, electrostatic problems, quality instability, and ink sticking phenomenon. They affect the entire production process and need to be well Grasp quality control.

Firstly, the control of the film material and the tension control in the production are the preconditions for ensuring good registration. The registration adjustment should not affect the running of paper. The price of materials in the in-mold label is high, and should be avoided as much as possible. Secondly, the control of drying should be followed. Effective drying does not affect the feeding of paper. The general cooling system does not function as it should. When dry, there is no support, and the film is heated. After the deformation, the effect of the cold water roller is not obvious. The infrared rays generated by the pure filtering uV device make the UV dry coal not enough heat guarantee, so it is recommended to choose a professional water cooling system. The improper handling of tension and drying has a direct impact on the speed of the machine and the efficiency of production. There is again the treatment of static electricity. Electrostatics has always been a major problem for film production. In addition to adding electrostatic devices during the process, additional control can be performed during the printing process, such as the use of inks and other accessories. Some devices have special handling devices for static electricity. All of these can effectively reduce the impact of static electricity on printing and die cutting. In addition, the collection of labels can also be plagued by static electricity. Even if we try every means in the die-cutting process, static electricity will be generated during the collection process. Larger batches can be collected by the US (COMCO) Cancor's rotation collection program, which is collected synchronously with the machine speed, and collected, counted, and stacked at one time, and directly packaged. For smaller batches, some custom solutions can also be used.

However, the use of in-mold labels also has some limitations. First, in practical applications, if adhesive labels are used, problems arise in the printing process. Even if they are reprinted, they will only waste some labels, even if they are already attached to plastic bottles. Not satisfied with the labeling style, only change the bottle body, the label can continue to use. However, the use of in-mold labels, if not satisfied with the printing or labeling process, will result in double waste of bottles and labels; secondly, the use of in-mold labels requires expensive molds. The special container blow molding or injection molding equipment increases the counterfeit cost while increasing the cost of counterfeiting and also increases the unit production cost of the container. In addition, if the blow molding process container is manufactured using the in-mold label, the shape of the container (curvature) must be considered. If the curvature of the container is too large, such as a round bottle, in-mold labeling may cause difficulty in exhausting. In addition, if the volume of the blow-molded container is too large, the in-mold label should not be used.

Relying on customers with their own advantages

The reason why in-mold label printing is used by more and more people is inseparable from its many advantages.

Beautiful appearance. The use of in-mold labels is undoubtedly very innovative and beautiful, inlaid firmly, waterproof and damp-proof. Hand feel is smooth, especially for daily chemical products with labels as main packaging. Since the in-mold label is naturally integrated with the bottle body and deformed with the deformation of the bottle body, no blisters, wrinkles, etc. will occur. In addition, in-mold labels use film and paper materials in foreign countries. Many film materials are used in the country. The surface of the film does not absorb ink. Therefore, the label has a bright color and a strong three-dimensional effect. The color effect is obviously better than that of paper materials, and it can perfectly reflect the exquisiteness. Patterns and small text. The in-mold label is tightly integrated with the bottle body, and the adhesiveness between the label and the container is good. When the container is warped and pressed, the label is not separated from it, and it can resist collision, scratching and pollution during production and transportation, so that the label can be Maintain integrity and aesthetics over time.

Security performance. Currently in China, only a handful of companies provide in-mold labeling services because of the large investment in disposable equipment. In the mold design, label printing and processing labeling forming process contains many changes, so there are technical barriers in the label within the mold, in order to counterfeit is not an easy task. The development of self-adhesive labeling technology in China is very mature, so imitation is quite easy. The in-mold label is produced together with the bottle body and cannot be faked unless the bottle body is copied together. However, this technology is only known in a few domestic enterprises, and the use of in-mold labels requires special molds and the production cost of the molds. Higher (a set of molds of several hundred thousand yuan) improves the difficulty and cost of counterfeiting.

Potentially reduce costs. At present, the price of in-mold labels is twice that of self-adhesive labels, which largely hinders the promotion of in-mold labels. However, if the direct screen printing label colors exceed four colors, the cost is the most expensive of the three conventional label printing methods. From the point of view of the cost of the label material, the in-mold label does not require a backing paper, so the material cost has a certain space for decline. And, the tag is embedded in a plastic bottle to increase the strength of the plastic container, reduce the amount of resin used in the container, and reduce the storage capacity of the plastic bottle. However, due to the use of in-mold labels, special die-cutting equipment and labeling equipment are required during the printing process, and the printing process needs to pay attention to electrostatic treatment, so the cost of printing the in-mold labels may be higher than that of the conventional labels. Experts pointed out. With the deepening of domestic understanding of in-mold labeling, promotion and improvement of in-mold labeling technology, its price will surely be able to reach the level acceptable to customers.

Environmental advantages. The environmental protection function of the in-mold label is also one of the reasons why manufacturers favor it. Since the in-mold label is completely integrated with the bottle body and has the same chemical composition, it can be recycled together, and the recycling rate is higher. No adhesive label can do this, it is separate from the bottle body, and the label above may be difficult to remove.

The future of the label market

Judging from the development situation at home and abroad, in-mold labels are mainly used in daily chemical products, oil industry, food industry, and pharmaceutical industries, such as shower gel, lubricants, coffee, and high-grade pharmaceutical packaging. Although the time for in-mold labels is not long, it is attracting more and more manufacturers' attention. In Europe and America, the development of in-mold labeling has begun to enter a stable development path. In China, in-mold labeling is developing at a rapid rate of 70%. Looking into the future, in-mold labels will launch strong challenges to sticker labels and will eliminate paper molds