In-mold labels have two printing methods

The in-mold label is currently commonly used as a plastic film substrate, printed in a conventional manner, with a layer of UV or EB curing varnish applied to protect it, and the backside of the label is coated with a solid chemical binder. In-mold label materials are suitable for a variety of printing processes and different inks, including: screen printing, UV letterpress printing, flexographic printing, gravure printing, and lithographic offset printing. Before selecting the ink, the adhesion, scratch resistance, and chemical resistance of the ink on the in-mold label material should be tested according to the requirements of the final application.

There are two kinds of printing processing methods for in-mold labels: web printing and sheet-fed printing.

1. Web printing processing: divided into on-line processing and extension multiple processing. These two processing methods are related to the factory's own equipment and label design requirements. If the printing process is carried out with a label with gilt pattern and the printing press is equipped with round round hot stamping and die cutting device, the processed label can be formed at one time; if there is only a separate hot stamping machine and die cutting 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 roller, it is more suitable for mass production.

2. Sheet-fed printing process: usually silk screen and offset printing. In this way, multiple processes are performed on multiple machines. The printing process is related to the process design. The process is more flexible, the plate making cost is lower than the reeling mode, and it is suitable for small batch production. The printing effect is good, and the screen printing field and the offset printing layer are printed. Both are better than web printing.

Offset printing process

1. Offset features

A. It is superior to other printing methods in the printing quality of small outlets.

B. The effect of on-line printing, on-site printing, and color saturation is inferior to other printing methods.

C. The control of color difference is more difficult than other printing methods.

D. For short-run business, the production cost of offset printing is lower than other printing methods.

E. It has the advantages of flexible production and rich printing layers. It is suitable for in-mold labels with high requirements for small batches and varieties, and is more suitable for the current status of the label printing market in China.

2. Offset printing process

A. Appropriate amount of dusting, printing materials should not be too high,

B. It should be fully aged after printing so that the ink will be dry. After printing, it must be coated with gloss oil to ensure the quality of the printed product.

C. In the printing, due to the poor hygroscopicity of the substrate, the amount of fountain solution should be reduced by 10% to 15% compared to the printed paper product (whichever is the case). Excessive dampening solution can lead to false drying and ink emulsification in printing. The pH of fountain solution is controlled between 6 and 6.5.

3. Offset printing equipment: most of the domestic printing companies use Heidelberg sheetfed offset printing machine series

Speedmaster CD74 - Features of medium format sheetfed offset press

* Wide range of substrates, from thin paper to hard cardboard to plastic film,

* Suitable for high-speed long-lived jobs, fully automated preparation and easy-to-control feeder systems,

* The digital CP2000 printing control system supports the quick change of paper format and paper baskets.

Flexo process

Flexo printing is the mainstream method of packaging and label printing in Europe and the United States. However, due to the imperfections of related facilities such as flexo plate making and die cutting, the current market share is small. However, the rapid development of flexo printing in recent years is an important development direction of label printing.

1. Flexographic features

A. With the CDI plate making technology of computer direct plate making, it can obtain better dot quality and saturated printing color.

B. The advantages of one-step molding and multi-process combination that cannot be compared with other printing methods.

C.Using UV ink printing, making the printing color more colorful, fast drying, high efficiency of a molding, suitable for mass production,

D. Poor ink adhesion, poor grading effect, generally after UV printing to be glazing.

2. Flexographic equipment

The foreign models are mainly the Gallas and Mai Andy; the domestic models are mainly Shanghai Ziguang.

(1)GullasEM280 narrow-width flexographic press is the ideal model for high-quality, low-cost and mid-to-long-length label production. Its main features are:

A. Simple operation, easy cleaning, short preparation time

B. Quickly change the platform and quickly replace the ink, can be converted in printing mode within a few minutes, the printing process mix is ​​flexible,

C. The unit can be added at any time. It is the ideal model for flexo and UV printing.

(2) Shanghai Ziguang

YR420/450 series is a flexo printing machine. It uses water-based ink and is suitable for food packaging and printing. Among them, the main features of YR420 Web Flexo Press:

A. It has the functions of quantitative paper feeding, UV polishing, waste rewinding, longitudinal slitting, etc.

B. Equipped with PLC controller, coil rectifying device, static elimination device, UV curing device, etc.

C. Can increase UV printing, stickers printing, flip printing, hot stamping, punching and other functions,

D. Suitable for printing stickers, coated paper, cardboard, aluminum foil and plastic film and other printing materials, is the ideal equipment for printing high-grade various types of packaging boxes, bottle posts, labels.

Gravure printing process: The number of gravure printing products in North America is absolutely dominant.

1. Gravure features

A. In the field printing effect and color saturation is better than offset printing, ink is thicker, the color transition of printing products is natural, but the text performance is inferior to offset printing.

B. Better than offset printing and embossing in color difference control

C. The longest paper path, which is more likely to generate static electricity than other printing methods,

D. Long time of plate making and high cost. It is not suitable for medium and short-run label printing business.

E. The ink layer is thick and has the best scratch resistance, and the printing speed is high. It is especially suitable for printing large-volume long-lived jobs.

F. Reel continuous printing, high output, low cost,

2. Gravure printing equipment

Domestic manufacturers such as Shaanxi Beiren and Zhongshan Sunde.

Shaanxi Beiren gravure printing machine is suitable for the printing of plastic film, tipping paper and other packaging materials.

Resin letterpress printing

1. Resin Relief Printing Features

A. The quality of printing fine dots is worse than other methods.

B. The printing plate has lower resistance than the gravure and flexo plates.

C. It is easier to print on the control of color difference than offset printing, but it is not as good as gravure printing and flexo printing.

D. Platemaking costs and cycles are lower than gravure and flexo,

E.Using UV ink printing, the printing color is brighter, faster and faster, and the efficiency of one-time molding is high. It is suitable for medium and large batch production.

2. Embossing equipment

Overseas mainly Ko-Pack and Luotie

The series of center impression cylinder printing presses manufactured by Japan Ko-Pack Co., Ltd. is a representative model of CID high-speed label printers. Its advantages are the small transmission error of substrates and accurate overprinting; the printing speed can reach 100m/min; Small, low site costs, it is suitable for the Chinese market.