Many plastic composite flexible packaging products require high transparency, necessitating the use of large areas of blank base film for lamination. However, in dry lamination processes, poor or decreased transparency often occurs, failing to meet quality requirements. For example, the finished product may appear "foggy," exhibiting phenomena such as "small spots," "wavy fish scales," "silky lines," "mushroom-like clouds," and "water splashing," affecting the transparency of the composite product and, in severe cases, rendering it unusable. Our factory has encountered these problems, impacting the quality of the composite products to varying degrees.

After extensive observation and experimentation, our factory has developed a practical solution, which has begun to show results.

"Foggy" Phenomenon and Countermeasures

When the composite product first comes off the machine, the blank areas appear "foggy," and this occurs randomly. It might appear on one sheet, not the next, and then reappear after a few sheets, with no consistent pattern. If the contents are filled in and observed under a 40-watt fluorescent light, the impurity is clearly visible.

We have noticed that this phenomenon is more likely to occur when laminating with single-component hot-melt adhesives than when laminating with two-component reactive adhesives, and it is more likely to occur in BOPP/OPP and BOPP/CPP structures.