Comment


Static charge: The invisible disruptor in roll-to-roll production By Irene Eggink, application engineer, Contiweb


I


n high-speed Roll-to-Roll (R2R) production, small and invisible forces can have a surprisingly large impact. Materials that should run smoothly suddenly start to misbehave. Webs may curl, sheets stick together, or products become diffi cult to handle. These issues often seem random and tend to return, even after adjustments to the process.


Operators typically look for mechanical causes or material inconsistencies. Rollers are cleaned, tensions adjusted and substrates replaced. Yet in many cases, the root cause is neither mechanical nor material related. It is something far less visible, but just as infl uential: static charge.


UNDERSTANDING STATIC CHARGE IN PRODUCTION


Static electricity occurs when two surfaces come into contact and then separate, causing electrons to transfer. One surface becomes positively charged, the other negatively. In hygroscopic materials such as paper, carton, nonwovens, cotton textiles, or foil fi lms, this charge imbalance accumulates on the surface (see Figure 1).


The key factor here is moisture. Under normal conditions, water molecules help conduct and dissipate electrical charge. When materials are dry,


conductivity drops and the charge has nowhere to go.


In R2R processes, this eff ect is amplifi ed. Every roller, winding step, or contact point generates additional charge (Figure 2). At higher speeds, this buildup increases rapidly. What starts as a small imbalance can quickly grow into signifi cant electrical potential.


This leads to familiar production issues:


• Sheets sticking together • Webs drifting or curling • Complex web tension & guiding • Dust attraction • Feeding and stacking problems


In extreme cases, static charge can even create sparks, posing safety risks in processes like printing or coating. WHY MOISTURE MATTERS


Moisture plays a crucial role in controlling static. Water molecules act as tiny conductors, allowing charge to move and neutralise. When moisture levels drop, this natural balancing mechanism disappears.


From a practical perspective, this means that dry materials are far more prone to static-related problems. They attract dust more easily, stick to machine parts, and behave unpredictably during handling.


TAKING CONTROL OF STATIC CHARGE The most eff ective way to reduce static is simple and straightforward: restore moisture.


By applying a controlled amount of water to the substrate, surface conductivity increases. This allows electrical charge to dissipate naturally, stabilising the process. Once the charge is neutralised, materials behave as expected again. Sheets separate cleanly, webs track consistently and machines can run without interruptions.


However, for certain materials such as coated papers, fi lms, or synthetic nonwovens, water alone may not be suffi cient. These materials tend to dry quickly or have inherently low conductivity. In these cases, antistatic additives can be used. Applied together with or within the moisture layer, these additives create a temporary conductive surface. This helps maintain stability, even under challenging conditions like high speeds or low ambient humidity.


FROM INSTABILITY TO CONTROL Contiweb’s fl uid application technology enables the precise and uniform application of moisture, with the option to incorporate antistatic additives. By restoring surface conductivity exactly where needed, static charge can be eff ectively dissipated, resulting in a stable and predictable production process.


Overview of different materials with positive and negative charge


These materials will give up electrons when in contact with other materials


These materials will attract electrons when in contact with other materials


Figure 1: Materials on the left tend to charge positively upon contact; toward the right they become more neutral, and further right tend to charge negatively.


32


April 2026


www.convertermag.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42