1. The heat resistance of the surface substrate film is poor;

2. Improper tension matching control of composite substrate during the composite process leads to residual stress after curing and shaping, especially when the composite film thickness is relatively thin.

3, the thickness of the composite film is not consistent;

4. Insufficient cooling;

5. Insufficient curing time;

6. In the longitudinal hot sealing blade part, the running track of the composite film is not straight;

7. The heat sealing temperature is too high or the heat sealing time is too long;

Then, now that we know the reasons, we should make corresponding adjustments to avoid unnecessary losses. The following are some countermeasures we summarized:

1, re-choose the surface of the substrate film, remember not to be cheap to choose a little knowledge;

2. Adjust the tension of each part of the compound processing equipment, and try to make the shrinkage rate of the two kinds of compound base materials equal;

3. Adjust the floating roller tension during compounding to make the thickness as consistent as possible;

4. Cool thoroughly;

5, fully mature, but also can not make the material too ripe or easy to cause adhesion, this degree must be mastered;

6. Select the internal sealing substrate with low temperature heat sealing property;

7. Adjust the heat sealing temperature to the appropriate temperature.

These are some of the reasons that cause food packaging to become warped after holding products and some of the solutions to the problem can be resolved hope that the above will help you.