What are the factors affecting the quality of PET self-adhesive die-cutting
The main factors affecting the quality of PET self-adhesive die-cutting are self-adhesive surface materials and adhesives.
1. Self-adhesive surface material:
During the die-cutting process, the die-cutting knife must cut off the surface material and adhesive layer of the self-adhesive to complete the die-cutting process. Therefore, the self-adhesive surface material is an important factor affecting the quality of die-cutting. Choose the appropriate die cutter according to the self-adhesive surface material.
Generally, suppliers offer two types of die cutters: unhardened die cutters and commercially printed die cutters. When die-cutting paper self-adhesive labels, you can choose a die-cutting knife without hardness treatment; if it is a film self-adhesive label, you must choose a die-cutting knife with hardness treatment to ensure the quality of die-cutting.
The design rarely causes die-cutting quality issues, but the special fillers in the paper are very abrasive to the die-cutting knives. In order to prolong the service life of the die-cutting tool, the manufacturer adjusts the blade angle of the die-cutting tool to 75°~90°.
Commonly used film self-adhesive surface materials mainly include: PE (polyethylene), PP (polypropylene), PET (polyester), polyolefin, PVC (polyvinyl chloride), PS (polystyrene), etc. Films place higher demands on the die-cutting process than paper.
Because the film has strong toughness, especially the toughness, when the PET material is cut with an ordinary die cutter, the blade is not strong enough, and it is processed after digital printing. The service life of the die cutter is not long. After the mold is cut for a period of time, the self-adhesive label part cannot be cut off, and the waste edge pulls the label from the backing paper.
Therefore, when choosing a die-cutter, be sure to choose a blade with a hardness treatment. The best hardness is above 58, and the blade angle is 37°-75°. The smaller the angle, the sharper the blade and the easier the die-cutting.
Adhesives used in self-adhesive materials are divided into acrylic water-based latex and rubber-based hot-melt adhesives. Due to the small cohesion of acrylic water-based latex, mold cutting is easy to evaluate, and there is no special requirement for mold cutting tools and die-cutting environments, which can well guarantee the quality of die-cutting.
However, the cohesive force between the hot melt adhesive molecules is relatively large, and the die-cutting tool and environment are strict. The die-cutting knife must completely cut off the adhesive layer to ensure that the enterprise discards it normally, otherwise the label will be removed from the backing paper.
In addition, due to the weak activity of hot melt adhesives at low temperatures, hot melt adhesives have higher requirements on the processing environment. During the discharge process, because the bonding force between the self-adhesive surface material and the backing paper is too small, it is easy to cause "flying marks".
The above are the two common factors that affect the quality of die-cutting about PET stickers and other types of stickers.
A perfect PET self-adhesive finished product requires layers of processes and checks before it can be made. The die-cutting quality of PET self-adhesive labels is affected by many factors such as die-cutting methods, precision of die-cutting equipment, die-cutting tools and self-adhesive materials, and is also related to factors such as operator proficiency, processing links, and static electricity. .