Summer arrives before we know it-and with it come dramatic shifts in temperature and humidity that can throw self-adhesive label production into disarray. From printing to application, these environmental changes often trigger a host of problems. If left unaddressed, they can disrupt operations and even lead to costly losses.
In this article, Boniron highlights three common summer-related issues with self-adhesive labels and offers practical guidance to keep your production running smoothly.
01 – Curling During Printing
Most self-adhesive labels are printed using UV inks. During the UV curing process, moisture in the self adhesive label material evaporates rapidly. Since the face stock and the backing paper respond differently to moisture loss-shrinking at unequal rates-the material tends to curl. This is especially noticeable with film-based face stocks paired with paper backing. While the film retains its moisture, the paper backing loses it quickly and shrinks, causing the label to curl downward.
If the printing workshop has low humidity, the backing paper cannot reabsorb moisture from the air, and the curling persists-sometimes severely hampering efficiency. On the other hand, when workshop humidity is properly controlled, the material can quickly regain moisture after UV curing, minimizing curl and keeping production on track.
✅ Key takeaway: Maintaining appropriate humidity levels in the workshop is essential during the summer months.
02 – Curling After Sheeting
Many finished labels require sheeting (cutting into individual sheets). In some cases, labels curl sharply right after sheeting, making standard packaging impossible. Under normal conditions, tension in the face stock is released during die-cutting and matrix stripping, so severe post-sheeting curling shouldn't occur. So why does it happen?
This issue is typically driven by a combination of improper material selection and poor humidity control. Self-adhesive materials come with various backing paper weights-for example, glassine paper (~60 g/m²), PE-coated paper (~95 g/m²), and cardstock (~120 g/m²). As a rule of thumb, materials with backing paper below 80 g/m² are not recommended for sheet-cut finished labels. Lighter backing papers are highly sensitive to humidity changes, expanding and contracting easily, which leads to pronounced curling after die-cutting and stripping.
✅ Best solution: Opt for materials with a heavier backing paper. Higher basis weight reduces humidity-induced deformation, making it far easier to keep labels flat after sheeting.
03 – Variations in Roll Tightness
During summer, it's not uncommon to encounter raw material rolls that have become either too loose or too tight-especially after being stored for a while. In severe cases, the material may even become unusable. The root cause? Significant humidity fluctuations cause the self-adhesive material to gain or lose moisture, altering tension and affecting roll integrity. This also explains why the cores of certain materials-particularly film-based face stocks-may protrude during use.
✅ Recommended practice: Reduce inventory levels and shorten storage cycles during summer. Strengthen warehouse management with a strict "First-In, First-Out" (FIFO) policy. While most materials remain stable within 7 to 10 days of arrival, it's advisable not to exceed a storage period of 15 days to avoid quality issues.
Final Word
Summer doesn't have to be a season of production headaches. By understanding how temperature and humidity affect your materials-and by taking proactive steps in workshop control, material selection, and inventory management-you can maintain consistent quality and avoid unnecessary losses.
Stay ahead of the heat with Boniron.
