Difficulties in die-cutting self-adhesive labels-1

Die cutting is an important part of self-adhesive label production. In the die-cutting process of self-adhesive labels, we often encounter some problems, which will lead to a significant reduction in production efficiency, and may even lead to the scrapping of the entire batch of products, causing great losses to the company.

1. Ink drops on the edge of the label after die-cutting: Some labels are designed to be bleeding die-cutting, that is, die-cutting where there is a printed pattern, which requires a die-cutting knife to cut where there is ink printing. In this case, it is often encountered that after the label is die-cut, the ink falls off where the label is cut. If it is a film-coated product for bleeding die-cutting, the film and ink may fall off together. Analyzing the reasons, there are mainly two factors that lead to this phenomenon.

self-adhesive labels

One is due to the surface adhesion of the printing material, also known as the surface energy of the printing material. Generally speaking, in order to make the ink adhere to the surface of the material, the surface energy should not be lower than 38 dynes. If good ink adhesion is required, the surface energy of the material need at least 42 dyne or more, otherwise, there will be problems of ink falling off.

 

The second is that the ink adhesion is not enough. Some inks have quality problems or do not match the printing materials, which may also easily lead to weak adhesion of the ink after printing. In this case, after the label is printed and then die-cut, the ink is more likely to fall off from the edge of the die-cut. Therefore, it is recommended that the printing factory conduct a tape test on the printed sample when it is on the machine, and if the test effect meets the standard, it will be mass-produced. If you encounter insufficient ink adhesion, you can replace the ink to solve it.

self-adhesive label

2. Glassine backing paper materials are cut and curled: There are two common ways of receiving self-adhesive labels: roll packaging and sheet packaging. Among them, the sheet packaging needs to cut the self-adhesive material. Generally speaking, the self-adhesive material used for sheet packaging has a thicker backing paper, and its weight is often above 95g/m2, but sometimes it is necessary to cut the thinner glassine backing paper into sheets. This is likely to encounter the problem of curling of the receiving material.

 

The main reason for glassine backing material to curl after cutting is: the moisture content of the backing paper will change drastically due to the influence of the environment, and the change in the moisture content of the backing paper will cause the paper to shrink or expand violently. Since the self-adhesive material is a composite material, the shrinkage rate of the backing paper and the surface material are different, and the deformation rate of the backing paper and the surface material will be different under the influence of humidity changes under the same environment. If the deformation of the backing paper is less than that of the face material, the glassine backing material will curl upwards, otherwise, it will curl downwards.

 

Once such problems are encountered, it is necessary to control the humidity of the production workshop as much as possible, so that the relative humidity of the production workshop is controlled between 50% and 60%. Such a humidity range is relatively middle, and the material deformation will not be particularly severe. If the material has been deformed, a simple baffle can be placed at the paper output position of the die-cutting machine receiving table to raise the paper output position so that the materials can be collected normally and then sorted.

self-adhesive sticker


Post time: Feb-13-2023