Flexible packaging is one of the most common packaging methods. The reason for flexible packaging’s popularity is due to its lightweight construction and its material savings when compared to rigid packaging.
The construction of flexible packaging is the usage of laminating adhesive to bond different layers of film, foil, or paper together to form an effective structure to protect the goods within the packaging. The effectiveness of bonding and sealing of the different substrates will involve having the right adhesive mix ratio, the right coating weight, the right drying temperature and time, the right pressure, and the right dyne level of the substrate. Some of the common coating and lamination adhesive issues include:
- Low bonding strength: the bonding strength for lamination is usually measured in Newtons. The bonding newtons needed will be dependent on the application of the flexible packaging. Low bonding strength between substrates is usually cased by insufficient adhesive coating weight, poor adhesive wetting due to the surface of the substrate, improper temperature or pressure from the nip roller, insufficient adhesive drying, incorrect adhesive or incorrect mix ratios.
- Tunneling in laminate: is the delamination of the substrate in certain areas of the lamination, forming a tunnel-like appearance. When tunneling appears, it is both detrimental to the appearance and packaging performance. Tunneling is often caused by the differences in moisture content in the substrates, the insufficient adhesive cure, the imbalance of web tension or improper rewind tension and taper settings, and excessive coating weights.
