How to deal with ink loss at the edges of self-adhesive material after die-cutting?

Die-cutting of self-adhesive materials is an important process in the production of self-adhesive labels. During the die-cutting process, we often encounter issues that result in a significant decrease in production efficiency and may even lead to the rejection of the entire batch of products, causing substantial losses to the company. In this session, we will explore how to address the problem of ink loss at the edges of labels after die-cutting.

Some labels are designed to be bleed-die-cut, which means that the die-cutting is done where there is ink printing. In such cases, it is common to experience ink loss at the cut edges of the labels. If bleed-die-cutting is performed on laminated products, there may also be instances where the film and ink come off together. There are two main factors that contribute to this phenomenon.

1. Insufficient ink adhesion.

Some inks may have quality issues or may not be compatible with the printing material, which can result in poor adhesion of the ink after printing. In such cases, if bleeding occurs after printing, the ink is more likely to come off from the die-cut edges.

Therefore, it is recommended to test tape samples on the machine and proceed with mass production only if the test results meet the standards. If the ink adhesion is insufficient, replacing the ink can help resolve the issue.

2. Low surface energy of the material.

The surface adhesion of the printing material, also known as surface energy, is an important factor. Generally, to ensure ink adhesion to the material surface, the surface energy should not be lower than 38 dynes. If good ink adhesion is desired, the material surface should have a surface energy of at least 42 dynes; otherwise, ink loss issues may arise. Materials with surface energy lower than 38 dynes cannot firmly adhere to the ink after printing. In such cases, if bleeding occurs again, die-cutting can easily cause the ink to come off at the edge of the cut line.

In this situation, it is possible to replace the material. If the material cannot be replaced, another option is to try printing a primer on the material surface to increase its surface tension and ensure that the ink does not come off during label die-cutting.