Die-cut self-adhesive label materials

The die-cutting quality of self-adhesive materials is related to many factors: such as die-cutting method, equipment accuracy, knife template accuracy, blade matching, material characteristics of the backing plate, etc. In addition, the die-cutting quality is also related to the characteristics of the self-adhesive materials, such as the different properties of the top paper, adhesive and backing paper, and the die-cutting characteristics of various self-adhesive materials are also different.

1. Types of surface materials:

   Surface materials can basically be divided into two categories: paper and film. Die-cutting paper materials is the combined result of tool cutting and paper stress breakage. That is, the blade cuts downward while also squeezing the paper to both sides. Therefore, a relatively blunt knife can cut the self-adhesive. When analyzing samples, we often see some labels with burrs. This is due to the thick fiber of the material, which is hard pressed by the knife rather than cut. Based on the die-cutting characteristics of paper materials and considering the wear life of the blade, the angle of the flat die-cutting blade is usually specified as 5.2°.

   The principle of die-cutting of film materials is slightly different from that of paper materials, because most film materials are tough and will not break naturally, so they must be completely cut through or at least four-fifths of the thickness, otherwise the labels will be peeled off together when the waste is discharged.

Therefore, the blade of the die-cutting film material must be sharp and hard, and a small-angle die-cutting knife must be used. The blade angle is usually 3.0° to 4.2°. If a large-angle die-cutting knife is used, not only will die-cutting be difficult, but the blade will not be sharp and the surface material will not be cut through, but the bottom paper will be broken.

2. Strength of surface material

   The strength of the surface material is related to the thickness of the surface material, fiber (polymer) structure and its own humidity. In the die-cutting process of self-adhesive materials, the factor most closely related to the surface material is the waste discharge speed. The greater the ambient humidity, the weaker the strength of the material after it gets wet, making it easy to break or even unable to discharge waste.

3. Thickness of surface material

   The thickness of the material directly affects the depth of die-cutting. Generally speaking, the thicker the material, the easier it is to die-cut. Because the thicker the material, the greater the die-cutting tolerance, and the smaller the chance of cutting through the backing paper. On the contrary, if the material is thin, it is easy to cut through the backing paper. For example, 80g/m2 and 60g/m2 are die-cut on the same flat label die-cutting machine, and the printing surface material is the same as the bottom paper.