Aluminum foil bags have been widely used in various fields and are popular packaging materials in the industry. But the aluminum foil packaging bag occasionally folds, what is the reason?
One is raw material reasons. For the edge fold, usually: 1) the material is not heat resistant, and the high temperature stamping material wrinkles; 2) The quality of the heat sealing material is poor, the sealing temperature is too high or the heat sealing performance is unstable; 3) glue and ink heat resistance is not enough; 4) Glue and ink in the bleaching process residual solvent too much, in the bleaching process accumulation and volatilization lead to foam wrinkling and other phenomena; 5) The heat resistance of glue and ink is not enough; 6) There is too much residual solvent in the glue and ink, causing the foam to wrinkle.
The second is the problem of not sealing, the reasons are usually: 1) the hot sealing knife of the bag making machine is parallel, the softness, hardness and flatness of the silicone do not meet the requirements of the hot sealing, and there are foreign bodies on the hot sealing knife; 2) The heat sealing knife temperature is too low, the pressure is too low.
It is recommended to check from the above points, pay special attention to the material source of the CPP, you can consult the supplier, and there is a bag making machine, such a thick material is recommended to use heavy bag making machine, which can provide a high heat sealing pressure and stable heat sealing temperature.
The third is the composite processing technology. The tension of the two composite substrate films is not balanced, the tension of one film is large, and the tension of one film is small. If the tension is too small, it is easy to form transverse folds, and if the tension is too large, it is easy to appear longitudinal folds. For example, al(aluminum foil)/pe is the composite of aluminum foil and polyethylene film, the extensibility of al is very small, and its tension can not be large (too much tension will cause moxa fracture). Pe will extend in the event of heat, the tension will stretch, and when the composite film is not cured, the pe aluminum foil film will shrink because of cooling and internal stress, resulting in artificial intelligence (aluminum foil) protruding, and the composite film will form a horizontal "tunnel" like fold. In addition, the amount of glue is insufficient or uneven, and the bonding force is not good, which will cause wrinkles in local places. The winding tension of composite film is too small, and the winding of composite film is more relaxed, which provides the possibility of shrinking of composite substrate film. If the winding tension is large, the composite film is tightly wound, and it is sent to the curing chamber immediately after getting off the machine, so that even if the composite process is uncomfortable, the four-layer aluminum foil bag will not fold. The temperature in the drying channel of the composite machine is too low, the exhaust air is not smooth, the residual solvent on the coated film is too much, the adhesive is not dry enough, and the drying film is not sticky enough, which will provide the possibility for the two composite substrate films to move each other, thus forming the composite aluminum foil bag to produce folds.
In order to solve this problem, firstly check one by one according to the above reasons, and pay special attention to the data source of the inner CPP, and negotiate with the supplier to adjust the data; Secondly, it is recommended to use a heavy-duty bag making machine for such thick data to provide a higher heat sealing pressure and a stable heat sealing temperature. You can also use the laboratory heat sealing instrument to do a heat sealing curve test on the data to prove the function of the data, so as to analyze the reason of the equipment or the data. Specifically, it can be avoided in several ways:
A: vacuum packaging aluminum foil bag composite film should be fully cooled before rolling.
Two: Adjust the compound pressure.
Three: Adjust the unwinding and winding tension to match the tension of each part.
Four: Replace the qualified film.
Five: Adjust the position of the film so that it does not deflect during transmission.
Six: Adjust the amount of glue, glue evenly.
Seven: Adjust the process parameters to make the adhesive fully dry and reduce the residual amount of solvent.
Eight: Adjust the parallelism of each guide roller.
Nine: vacuum packaging aluminum foil bag clean the surface of each guide roller, replace the damaged guide roller, and ensure that the surface of the guide roller is smooth, smooth and clean.
