In-mold Label Printing Process Overview - Offset Printing Process

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. The printing quality of fine dots is better than other printing methods.
B. It is not as good as the 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 short-run business, offset printing costs are 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. The amount of dusting is moderate, and the accumulation of printed 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 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 (instead of the non-dry version). 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 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 printing control system supports the quick change of paper format and paper baskets.