Adhesive overflow is one of the most common problems of self-adhesive labels, which can easily lead to label appearance defects, print contamination, poor peel, etc.. Therefore, it is particularly important to identify its cause, and develop appropriate solutions.
Adhesives for self-adhesive label materials are acrylic resin and rubber-based resin, both of which belong to pressure-sensitive adhesives. It is easy to deform under the influence of high temperature, high humidity and pressure, etc. Excessive temperature will make the fluidity of the adhesive greatly increased, especially in summer and rainy season. In addition, the amount of adhesive coating also may cause adhesive overflow, such as tire labels with relatively large amount of adhesive coating, more likely to overflow adhesive.
Therefore,in the summer, the workshop should maintain the appropriate temperature in the production of self-adhesive labels. Generally speaking, the temperature of the label processing and storage environment should be controlled at 23°C ± 3°C and the relative humidity should be controlled at 55% ± 5%.
When die cutting self-adhesive labels, the blunt edge of the knife will cause the label adhesive to flip and squeeze, resulting in overflow of adhesive on the edge of the label during die-cutting. Therefore, you must use a sharp knife for die-cutting.
In addition, the die-cutting pressure will also have a certain impact on the overflow of glue. Strictly control the die-cutting pressure. Too large die-cutting pressure will cause excessive extrusion of the label adhesive, while too small die-cutting pressure will cause adhesive wiredrawing in the process of die-cutting, thus forming glue overflow on the edge or surface of self-adhesive labels.
Excessive rewinding tension will cause excessive extrusion of the label adhesive, and even cause the label to slip on the backing paper, resulting in glue overflow.