Sealing temperature

The goal when sealing packaging, usually flow-wrapped pillow pouches, is to join the sealable packing material together in such a way that it’ll be closed with a strong hermetic seal. As the term implies, a “hermetic seal” isn’t just dust-proof. Instead, it also needs to prevent mineral oil contamination, oxygen, and water vapor from entering the packaging.

When using heat sealing with pillow pouches, time, pressure, and temperature are the primary factors used to produce a longitudinal seal and a transverse seal. In this process, the packing material runs over a forming shoulder and is formed into a tubular shape and heat-sealed with a longitudinal seal. Meanwhile, the transverse seal, also referred to as an “end seal,” is made with a sealing jaw. The temperature (or “sealing temperature” to be more precise) used to make these seals plays an essential role in heat sealing.

Being able to work with a wide temperature window for the sealing process is crucial when it comes to obtaining good packaging results, since paper is normally not as good a conductor of heat as plastic and it’s essential for production speeds not to be negatively affected when switching to paper. This is where Koehler NexPlus® paper comes in, as it’s characterized by low grammage and high strength, ensuring that its sealing performance is comparable to that of plastic. Accordingly, the ideal sealing temperature for Koehler NexPlus® Seal Pure, Koehler NexPlus® Seal MOB, and Koehler NexPlus® Advanced is between 110 °C and 200 °C depending on the specific packaging machine.