The packaging form of stand-up pouch is widely used in soy milk products. Compared with another packaging, stand-up pouch packaging is clean and convenient. You can open it when you want to drink it, and screw it up when you don't want to drink it without waste. And it can meet the different sterilization and preservation conditions in the production of soymilk, not only for 3 to 5 days under refrigerated conditions but also for about 1 month under normal temperature conditions. At the same time, soymilk for breakfast and ready-made soymilk also began to be packaged in stand-up pouches.

Three quality problems often occur in stand-up pouches, namely, bag leakage during use, uneven bag shape, and asymmetric bottom seal during bag making.

1. Bag leakage

The reasons for the leakage of stand-up pouches mainly lie in the selection of composite materials and the strength of heat sealing.

1. Material selection

Material of stand up pouch selection is important for leak prevention, the purpose is to improve the peel strength between the outer layer and the middle barrier layer, the barrier layer, the heat seal layer material, and the heat seal strength of the bag. Therefore, it is required that the surface tension of the composite surface of the film must be greater than 38 dyn/cm; the low-temperature heat sealing performance of the inner heat sealing film is better, and the surface tension of the heat cover must be less than 34 dyn/cm; Solid content low viscosity adhesive, high purity organic solvent.

2. Heat sealing strength

Low heat sealing strength is also one of the important factors affecting the leakage of stand-up pouches. When heat sealing, it is necessary to adjust the matching relationship between heat sealing temperature, heat sealing pressure, and heat sealing time. In particular, we should pay attention to exploring the heat sealing temperature of bags with different structures. Due to the different melting points of different types of plastic films, the heat sealing temperature is also different; the heat sealing pressure should not be too large, and the heat sealing time should not be too long, so as to avoid macromolecular degradation and heat sealing The layer is sheared by the heat sealing knife in the molten state at high temperature, which reduces the sealing strength. In addition, the four-layer sealing at the bottom of the stand-up pouch is the most critical part, and the heat-sealing temperature, heat-sealing pressure, and heat-sealing time can only be determined after sufficient testing and verification.

In the actual production process, the leakage test of the stand-up pouch should be done according to the different requirements of the contents. The simplest and most practical method is to fill the bag with a certain amount of air, heat seal the mouth of the bag, put it into a basin containing water, and squeeze different parts of the bag with your hands. The sealing and airtightness are good; otherwise, the heat sealing temperature and pressure of the leaking part should be adjusted in time. The self-supporting bag containing liquid should be treated with caution, and the liquid leakage can be detected by squeezing and dropping methods. The drop test method can also refer to the above-mentioned standards.

Fast Sincere is a company of flat-bottom OPP bags, which is fully committed to the development, production, sales, and optimization of the industrial structure of plastic packaging materials. The employees and the enterprise develop synchronously. The factory has professional assembly line production and manufacturing equipment, and independently completes a complete set of processes from raw material blowing, printing, compounding, bag making (folding, slitting), edge sealing, inspection, packaging, etc. According to customers' customized requirements, we can provide a one-stop service from design to production. The company is fully committed to the development, production, sales, and optimization of the industrial structure of plastic packaging materials.