Why does the opening of the composite vacuum bag curl?

After the production of composite vacuum packaging bags is completed, the phenomenon of curled bag openings often occurs. This is mainly because composite vacuum bags are made of multiple materials. Generally speaking, if there is mild curling and the flipping height is less than 0.05mm, then this is a normal phenomenon. If it exceeds such standards, there is a high possibility of defects in production, resulting in severe curling of the bag opening. So, why does the composite vacuum bag bag opening curl? How should we solve it again?

1. Tension mismatch is the main factor, and the film will inevitably curl towards the substrate with high tension and shrinkage. Especially for inner CPP and PE, the tension should be minimized as much as possible, and when composite with homogeneous materials, the unwinding tension should be high.

2. High drying temperature and high composite temperature. If the temperature is too high, it can easily cause the film to stretch. It is advisable to lower the temperature appropriately for BOPP and PE materials.

3. The winding tension and taper should be appropriate. Fully cool before winding to prevent shrinkage and increase in roll pressure.

4. The moisture absorption of the film is inconsistent. A typical example is nylon, which has strong moisture absorption properties. After absorbing moisture, the film elongates, causing internal rolling.

The above information is compiled by Jinde Packaging. Jinde Packaging is a manufacturer specializing in vacuum packaging bags, with more than 10 years of experience in vacuum packaging bag production and excellent equipment. It provides spot wholesale and small order customization services. Hotline: 15902743510