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Stand Up Pouch leak, bag type is not flat, undermation is asymmetrical, how to solve?

    Stand up Pouch often meet three quality problems in the production process. First, the phenomenon of bag leakage during use, second, the shape of the bag is not flat during the bag making process, and finally the bottom sealing is asymmetric.

1, stand up pouch leakage

    The reason for the leakage of Stand Up Pouch is mainly in the problem of composite selection and the problem of heat sealing strength.

STAND UP POUCH Material Selection

    Stand Up Pouch’s material selection is important for preventing leakage, the purpose is to improve the heat sealing strength of the outer layer and the intermediate barrier layer, the barrier layer and the heat sealing layer material, and the heat sealing strength of the bag. Therefore, the surface tension of the composite surface of the film must be greater than 38 dyn / cm; the low temperature thermal sealing performance of the inner layer heat sealing film is good, the surface tension of the heat cover must be less than 34 Dyn / cm; in addition, the ink to connect performance, high Solid low viscosity adhesives, highly purity organic solvents.

STAND UP POUCH heat sealing strength

    The heat sealing strength is also one of the important factors affecting the leakage of stand up pouch bags. Adjust the heat sealing temperature, heat sealing pressure, and heat sealing time when heat seals. In particular, pay attention to the heat sealing temperature of different structural bags, which is different from the melting point of different types of plastic films. The heat sealing pressure should not be too large, and the heat sealing time should not be too long, so as to avoid macromolecule degradation, the heat sealing layer is cut by hot sealing the knife in a high temperature melting, so that the sealing strength is lowered. In addition, the four-layer seal at the bottom of the upright bag is the most critical part. After sufficient test, the heat seal temperature, heat sealing pressure, and heat sealing time can be determined.

    In the actual production process, we should make the stand up pouch leak test according to the different requirements of the content. The simplest and practical method is to charge a certain amount of air in the bag, seal the bag, put it in the basin of water. If the bag is extruded,and there is no gas to escape, the bag sealing is good;Otherwise, the heat seal temperature and pressure of knife should be adjusted in time.The stand up pouch bag of the internal liquid should be cautious, and it can be detected by the extrusion and falling method, such as the filled water, sealing the mouth, according to the GB / T1005-1998 withstand voltage test method. The drop test method can also refer to the above criteria.

2, stand up pouch  bag shape is not flat

    Flatness is one of the metrics that measure the quality of the packaging bag. In addition to the material factors, the flatness of the self-supporting bag is also related to factors such as heat seal temperature, heat sealing pressure, heat sealing time, and cooling effect. The heat sealing temperature is too high or the heat sealing pressure is too large, and the heat sealing time is too long, which causes the composite membrane contraction deformation. Insufficient cooling causes insufficient type of heat seal, and cannot eliminate internal stress, so that the bag is wrinkled, so the process parameters should be adjusted, and ensure that the cooling water circulation system is working properly.

3, Stand Up Pouch’s symmetry difference

    Symmetry not only affects the appearance of Stand Up Pouch, but also affects its sealing performance.

The most common asymmetry in Stand Up Pouch is often reflected in the substrate portion. Since the material tension control is not properly controlled, the bottom circular hole deformation is caused, or the wrinkles are generated by mismatch with the material tension, and the heat sealing strength is lowered. When the bottom metal hole is deformed, the discharge tension should be appropriately reduced, and the waiting time is increased in the heat seal to make a correction, so that the four-layer intersection of the bag is fully hot. In addition, the bag asymmetry will also be related to the factors such as photoelectric tracking, discharge, cursor design, rubber roller balance, stepper motor or servo motor. This issue is based on different products, and different bags can be solved in specific operations.


    The development of the stand up pouch bags has brought new economic growth highlights for the soft packaging industry. Because they can bring endless business opportunities, many soft packaging companies have introduced corresponding equipment and production technologies to promote rapid development of enterprises.


    Duxia package is a manufacturer specializing in the production of stand up pouches. We can customize  different kinds of stand up pouches by customer’s needs. In addition, the pattern design can be made according to customer needs. Welcome inquiry!

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