Cold weather can impact labelstock. Our Technical Consulting experts answer some basic questions they often hear about the effects of cold winter weather on label converting and storage:
• Why did our general purpose adhesive quit working?
A couple of factors may be at work. First, it may be an application temperature issue. An adhesive that has been applied outside during the warmer months of the year may no longer adhere when applied in the winter. Your customer may say they are applying the labels in a heated warehouse above 40°F (the minimum application temperature for most general purpose adhesives), for example, but you may need to remind them that if the labels are being stored or applied near the often-open dock door, the temperature may actually be in the twenties or thirties during cold weather. Also, make sure that the temperature of the item being labeled has had time to warm up to a temperature appropriate for label application.
• Should I store my label materials somewhere warm during cold weather?
Warmer than outdoor conditions, yes. But take care that your incoming rolls and converted labels aren’t stored particularly close to a heat source that could dry them out, causing curl issues. Keeping the labels warm, but not excessively wa., is the key. Make sure rolls have acclimated in the press area before converting.
• Why do I see more curl issues in the winter?
In colder weather, relative humidity (RH) indoors is much lower than in warmer months, causing pressure-sensitive materials to lose moisture into the drier air around them. Layflat products are designed to work at 40-55% RH, but often manufacturing and shipping areas will be at 20-30% RH in winter, which will induce moisture curl in label materials. The colder it is outside, the worse this problem will usually be. Film face/paper liner combinations will typically curl toward the finer because the film doesn’t contain any moisture to lose, while the finer shrinks and pulls the label downward.
Humidifying your handling and storage environment will greatly reduce curl issues in winter, as well as static, jogging, and stacking issues. Pack converted rolls into airtight bags before boxing to protect them from moisture fluctuations, and recommend to your customers that they only remove one roll at a time as needed from a carton or bag so the rolls stay protected from moisture fluctuations. Also, end-users should be advised to watch for condensation inside the plastic bags when they first bring them into a warm area.
• Why did my labels suddenly pucker and wrinkle during shipment?
Applied labels can pucker and wrinkle on long haul shipments, especially if it is a large label on an empty plastic container. Plastic containers tend to shrink more in cold weather than do the labels that are applied to them, which may cause puckering of the label. Obviously, the containers have to be shipped, but try to avoid shipping them over the weekend or holidays when they may end up sitting on a cold truck at a freight station.