Some precautions when labeling in the roll mold

When we carry out in-mold labeling, because of the different labeling items, the matters that need to be paid attention to are different. Let's take the reel as an example to take a look at some precautions when labeling in the reel mold.

1) First determine the design draft of the label. The shape of the label should match the contour of the container to be labeled, and the thickness of the label should be 60-100μm.

2) The paper core tube of the label material to be printed should be larger (such as 152mm). Because the larger the diameter of the paper core tube, the smaller the bending deformation of the material near the paper core, which can improve the deformation of the label after printing.

3) Before printing, the operator should determine the front and back of the label, that is, the printing surface layer and the adhesive layer. It can be identified by checking the surface tension of the label material or wiping the surface of the material with a solvent.

4) The printing machine must be equipped with an automatic control device for material tension to maintain the uniformity of the label material tension during the paper feeding process to ensure accurate overprinting. Compared with self-adhesive labels, in-mold labels have less paper feeding and rewinding tension during the printing process. Excessive paper feeding force will deform the in-mold label material, resulting in inaccurate subsequent printing overprinting; excessive rewinding tension will deform the in-mold label material, resulting in inaccurate subsequent die-cutting and more waste products. In actual production, the winding tension should be as small as possible, as long as the label material does not swing during winding.

5) The printing machine should be equipped with a corona device. The binding degree of label material and ink is mainly determined by the surface tension of the label material in the mold. When the surface tension of the in-mold label material is lower than 38mN/m, it must undergo corona treatment to ensure the adhesion of the ink on its surface. However, corona treatment also has certain negative effects. If the corona time is too long or the strength is too strong, excess charges will be generated on the surface of the label material, which will affect printing and even die-cutting.

6) The printing machine should be equipped with a static elimination device. The label printing process will generate more static electricity, so the printing machine should be equipped with a static elimination device. In addition, proper temperature and humidity can also reduce the generation of static electricity. It is best to keep the temperature of the printing workshop at (23±2) ℃ and the relative humidity at about 50%.

The above are some precautions when labeling in the reel mold. I hope that through the understanding of this knowledge, everyone can be better familiar with the labeling method.