What to Do About Adhesive Overflow in Self-Adhesive Labels? Remember These 5 Tips!

Recently, Label Sini received many inquiries from readers asking about adhesive overflow in self-adhesive labels. In fact, we have previously published several articles addressing how to solve adhesive overflow issues during the die-cutting process. If the overflow problem occurs during die-cutting, you can refer to the solutions outlined in those previous articles. However, if the overflow occurs after die-cutting or you want to prevent it beforehand, here are some summarized tips that might help:

01 Label Shape
Designing irregular-shaped labels (e.g., non-rectangular) makes them more prone to adhesive overflow compared to square or rectangular labels. During the die-cutting and waste removal process, inconsistent tension across the width of the roll can cause localized areas of high tension, leading to local adhesive overflow. Additionally, small square labels tend to bear higher pressure under the same conditions, which also increases the likelihood of local adhesive overflow.

Therefore, for die-cutting and waste removal of irregularly shaped labels:
Consider using reverse winding when rewinding;
Retain a certain width of waste edge on both sides of the irregular label (such as circular labels);

When winding finished labels onto the core, consider wrapping foam cotton or high-elastic sponge around the surface of the paper core tube.

02 Basic Judging Criteria Before Printing
When roll-fed self-adhesive material is unwound on the printing press, if there is no stringing or only slight stringing between layers, the self-adhesive material can be considered acceptable. Of course, the ambient temperature and humidity of the site should also be taken into account. For sheet-fed self-adhesive materials being fed on the offset press feeder, if there is stringing or adhesion between layers, the material can be deemed unqualified. This kind of interlayer stringing during feeding can cause misalignment of the material, resulting in registration problems during printing.

03 Adhesive Overflow After Printing and Die-Cutting
If the white material end face is severely stuck together, there will likely be noticeable stringing during printing unwinding, and adhesive overflow around the edges of the labels may occur after die-cutting. It's worth noting that adhesive overflow is also related to label displacement or shrinkage on the liner. During or after the die-cutting process, label movement during winding can lead to overflow on one side of the label, while label shrinkage can cause overflow around all edges.

04 Control of Winding and Unwinding Tension
Due to differences in processing materials, production processes, and printing equipment used, it is unrealistic to provide a single "correct" tension value. The ultimate result of tension control is reflected in the tightness of the wound roll. With customer approval, winding the rolls as loosely as possible is the best approach. During printing (including inline die-cutting), tension should be kept as low as possible without affecting print registration accuracy and post-processing requirements.

In any processing step, the winding tension should always be less than the unwinding tension, and the difference between the two should not be too large. To judge whether the winding tension is appropriate, if you lift a small roll after die-cutting and slitting with both hands, you should at least be able to use your thumb to freely push the end face up and down—this indicates appropriate winding tension. If the small roll feels like a "solid iron disc," then the winding tension is definitely too high.

05 Storage Environment Temperature and Humidity

The recommended storage and processing environment temperature for labels is 23±2°C, with relative humidity maintained at 55%±5%. High temperature and humidity can increase the fluidity of the adhesive. Summer and rainy seasons are often peak periods for die-cutting overflow problems. In short, there are many types of adhesives and face materials used in self-adhesive labels, and each has different die-cutting characteristics. Therefore, before producing self-adhesive labels, it is recommended that printers communicate in detail with material suppliers to determine the appropriate die-cutting process, thereby reducing label surface contamination caused by die-cutting overflow and meeting end-user application needs.

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