What to Do About Glue Overflow on Adhesive Labels? Remember These Tips!

What to Do About Glue Overflow on Adhesive Labels? Remember These Tips!

Recently, I've received quite a few questions from readers asking about glue overflow on adhesive labels. In fact, in previous articles, we've already shared several pieces on how to deal with glue overflow during die-cutting. If the overflow happens during the die-cutting process, you can refer to the solutions listed in those past articles.

But if the overflow occurs after die-cutting or if you want to prevent it in advance, here are some summarized tips that might be helpful:

01

Label Shape Design

Unlike square or rectangular labels, irregularly shaped labels are more prone to glue overflow. During die-cutting, irregular labels can experience uneven tension distribution, causing parts of the labels to overflow with glue. Small square labels are also prone to local overflow since they withstand higher pressure under the same force.

Therefore, for die-cutting and rolling irregular labels, it's recommended to use reverse rolling; leave some die-cut waste margin on both sides of irregular labels (like round labels); or wrap foam or high-elastic sponge on the core tube when rolling finished labels.

02

Basic Pre-Printing Overflow Checks

For roll adhesive materials, when placing them on the press, if there's no or just slight stringing between layers, the material is considered qualified. Of course, you should also check the temperature and humidity on site. For sheeted adhesive materials, if stringing or sticking occurs during feeding on an offset press, the material is considered unqualified, as this can cause misalignment when printing.

03

Printing and Die-Cutting Overflow

If the raw material sticks severely at the edges, stringing will be noticeable when unwinding for printing, and post-die-cutting glue overflow around the label edges is likely. Glue overflow is also related to label shifting and shrinking on the liner. Label movement during or after die-cutting can cause one-sided overflow, while label shrinking can lead to overflow around all edges.

04

Controlling Unwinding and Rewinding Tension

Because materials, production processes, and presses vary, giving a 'correct' tension value isn't realistic. Tension control shows in the tightness of the roll. Within the customer-approved limits, rolling as loosely as possible is best. During printing (including inline die-cutting), it's better to keep tension as low as possible without affecting registration or downstream processes.

In all processes, rewind tension should be lower than unwind tension, and the tension difference should not be too large. To check if rewind tension is suitable, pick up a small die-cut roll with both hands; if you can move the edges up and down with your thumb, the tension is right. If the roll feels like a "metal disk," the tension is too high.

05

Storage Temperature and Humidity

It's recommended to store labels at 23±2°C with 55%±5% relative humidity because high heat and humidity increase glue flow. Summer and rainy seasons are often peak times for die-cut glue overflow.

In short, there are many types of glue and face materials for adhesive labels, and different combinations perform differently during die-cutting. Therefore, before producing adhesive labels, printing companies should communicate with material suppliers about the proper die-cutting process to minimize overflow and avoid label surface contamination, ensuring the final product meets customer needs.