In-die label printing process development overview

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 for protection, and the back of the label 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. Better print quality than fine prints
b. It is not as good as other printing methods in terms of the printing effect of the lines, the field, and the saturation of the colors.
c. The control of color difference is more difficult than other printing methods.
d. For the 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. After printing, it should be fully aged to make the ink dry. After printing, it must be coated with varnish 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 (instead of the non-dry version). Excessive dampening solution can cause spurious drying and ink emulsification in printing. The ph value of fountain solution is controlled between 6 and 6.5.

3. Offset printing equipment: most of the domestic printing companies use the Heidelberg sheetfed offset press series Speedmaster cd 74 - medium format sheetfed offset press features:
* Wide range of substrates, from thin paper to hard cardboard to plastic film,
* Suitable for high-speed long-lived job, fully automatic preparation and easy-to-control feeder system,
* The digital cp 2000 print control system supports fast replacement of paper format and paper cassettes.

Flexo printing process Flexo printing is the mainstream packaging and label printing method in Europe and the United States. However, due to the imperfections in the related facilities such as flexo plate making and knife mold, 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. The characteristics of flexo a. The cdi platemaking technology with computer direct plate making 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. Apply uv ink printing to make the printing color more colorful, fast drying, high efficiency of one-time molding, suitable for medium and large batch production.
d. The ink has poor adhesion and poor grading effect. Generally, it needs to be glazing after uv printing.

2. Flexo equipment foreign models are mainly Gallas, Ma Andy; domestic models are mainly Shanghai Ziguang.
(1) The gullas em280 narrow-width flexo press is the ideal model for the production of high-quality, low-cost and mid-to-long-length labels. Its main features are:
a. Easy to operate, easy to clean, short preparation time for job adjustment,
b. Fast conversion platform and quick ink change, can be converted in printing mode within a few minutes, and the printing process is flexible and diverse.
c. Units can be added at any time, ideal for flexo and uv printing.

(2) Shanghai Ziguang yr420/450 series is a flexographic printing machine, using water-based ink, suitable for food and drug packaging and printing. Among them, the main features of yr420 web presses:
a. It has the functions of quantitative paper feeding, uv glazing, scrap rewinding, longitudinal slitting, etc.
b. 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. It is suitable for printing materials such as stickers, coated paper, cardboard, aluminum foil and plastic film. It is the ideal equipment for printing high-end various kinds of packing boxes, bottle posts and labels. Gravure Gravure Gravure is an absolute dominant product in North America.
1. The characteristics of gravure printing a. In the field printing effect and color saturation is better than offset printing, ink is thicker, the printing product color transition 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, 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. The characteristics of the resin letterpress printing a. In the fine print dot quality is worse than other methods,
b. The plate's resistance to printing is lower than the gravure and flexo plates.
c. It is easier to print than color offset in printing color control, but not as gravure and flexo.
d. Platemaking costs and cycles are lower than gravure and flexo,
e. Application uv ink printing, making the printing more colorful, fast drying, a high efficiency molding, suitable for medium and large batch production.
2. The embossing equipment abroad mainly consists of ko-pack and Rakuten. The class series of center-imprinting cylinder-type printing presses manufactured by Japan Ko-pack Co., Ltd. is a representative model of the cid high-speed label printing presses. Its advantages are that the substrates have a small transmission error and the registration accuracy is high. The printing speed can reach 100 m/min; the floor space is small and the site cost is low, which is suitable for the Chinese market.

Source: 21st Century Fine Chemicals Network