DY-L series Dyne pen usage

DY-L series dyne pen can accurately test whether the surface tension of the plastic film reaches the value of the test pen. Let users know clearly whether the plastic film is suitable for printing, lamination or aluminum plating, effectively control the quality and reduce tool delays caused by unqualified materials. And DY-L series dyne pen is not limited to plastic film, it can also test the surface tension of other flat materials.

In general, thin film substrates are energy-dependent for the formation of ink droplets, coatings, and surfaces. If the energy on the surface of the substrate is lower than the surface tension of the applied test solution, bead points will form and the line will shrink (as shown in Figure 1), which is called wetting. The original surface tension of most plastic substrates is relatively small, and the original surface tension of several polymers is roughly as follows:

The surface energy usually used as an ink solvent is: ethanol 22mN/m, ethyl acetate 24mN/m, and the preparation of ink needs to add resin, binder, pigment, and additives, and the surface tension should generally be 38 dynes to 42 dynes Because of left and right. The value of the surface tension of the plastic is related to the molding temperature, cooling speed, additives and whether it is treated or not. Therefore, the BOPP film commonly used in color printing must be corona treated before printing so that the surface tension cannot be less than the surface tension of the ink, so as to achieve wetting. ,Figure 1.

In Figure 1, θ is the wetting angle. Obviously, when θ>90°, it is not wet due to the small wetting tension; when θ<90°, it is wet; and when θ=0°, it can be completely wetted. It can be seen that the surface tension of the film must be at least 38 dynes, so that the wetting angle between it and the ink is less than 90°, so that wetting can be achieved, so that the printing effect is better.

If the surface tension of the film is to be further increased, or the surface tension of the ink is reduced, will the printing effect be better? Can the so-called wetting angle be zero? It can be accurately said that regardless of cost and physical feasibility, In theory, such a little bit of ink will cover the entire film, and the various colors will be mixed together, and the pattern will no longer be visible.

For most films, the surface tension of the film is tested before printing, and the dyne pen is required to be between 36 dyne/cm and 40 dyne/cm. Nylon requires about 52 dyne/cm, and PET requires about 48 dyne/cm to be equipped with a dyne pen.

How to use: Make the DY-L dyne pen perpendicular to the plane of the film, apply appropriate pressure, and gently draw a line on the surface of the film (see Figure 2). Generally, three adjacent dyne pens are required.

Analysis results:

1. If the lines are evenly distributed without any beads, it means that the surface tension of the film is higher than the index marked on the Dyne pen.

This case can be printed.

2. If the drawn line shrinks slowly, it means that the surface tension of the film is slightly lower than the index marked on the Dyne pen. In this case, the printing effect is not good.

3. If the drawn line shrinks immediately and forms bead points, it means that the surface tension of the film is lower than the index marked by the dyne pen, and it cannot be printed in this case.