Film self-adhesive characteristics and printing process (on)

Adhesive material is a polymer film, the surface of the absorbent is not printing inks, printing inks and dried adhesive film mode material surface comprising: a volatile, conjunctiva, crosslinking, curing, substantially no penetration mode, with the paper There is a big difference between self-adhesive materials. The surface energy of the film self-adhesive material is low, and must be pre-treated before printing to meet the requirements of wetting and leveling of the printing ink, otherwise problems such as poor adhesion of the ink may occur.

In addition to the drying problem, since the film self-adhesive material is a polymer, the free electrons on the surface are very unstable, and in a dry environment, friction generates a large amount of static electricity. Static electricity will affect the printing and processing of materials. Therefore, controlling static electricity, improving the environment, and increasing the corresponding configuration on the equipment must be paid attention to when printing film self-adhesive materials. Otherwise, the quality of printed matter cannot be guaranteed. In addition, the film self-adhesive material is sensitive to temperature changes and has large thermal deformation. Therefore, the drying (curing) temperature, printing speed, film thickness, and tension setting during printing must be matched, otherwise it is very easy to cause problems. .

Types and characteristics of commonly used film materials

The physical properties of common film materials are shown in Table 1. The surface tension is the surface tension value before the material treatment. It can be seen that the surface tension of the material after leaving the factory is basically lower than 38mN/m, and 38mN/m is the lower limit for ensuring the normal printing of the ink. Therefore, these film materials must be processed before they can be printed normally.
Table 1 Physical properties of commonly used thin film materials
Note: The GCX film is made by mixing a certain ratio of polyethylene and polypropylene resin and then co-extruding and uniaxially stretching. It is a polyolefin material.

In order to ensure that the ink is well fixed on the surface of the film material, we need to understand the surface tension requirements of the ink on the substrate, especially the film material, and pay special attention to it. Table 2 lists the requirements for different types of flexographic printing inks for the surface tension of different types of film materials before printing. Comparing Tables 1 and 2, we found that the untreated film material is basically not satisfactory, so the surface treatment of the film material is very important for printing.
Table 2 Requirements for surface tension of film-adhesive materials for flexographic printing inks (unit: mN/m) Table 2 Requirements for surface tension of film-adhesive materials for flexographic printing inks (unit: mN/m)

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