Flatness is one of the basic requirements of people for plastic flexible packaging, but in the actual production process, after the bag is heat-sealed, wrinkles are prone to appear at the seal, which affects the appearance and usage rate. So how to avoid this problem?

1. Material problem If the material is not temperature-resistant enough, the sealing position will easily wrinkle after high-temperature sealing and ironing. For example, the material of BOPP/PE is relatively soft and lacks hardness, so if the temperature is too high during heat sealing, it is prone to wrinkles. It is recommended to add a film with good flatness and certain hardness, such as PET film, in the middle layer of the packaging bag composite material, so as to solve the wrinkle problem caused by the material.

2. Heat-sealing time and temperature If the heat-sealing temperature is too high, the packaging bag cannot withstand such a temperature, and it is easy to be scalded and wrinkled. However, the heat-sealing temperature is not enough, and it is easy to cause the heat-sealing strength to be low, and the heat-sealing effect cannot be guaranteed. In the case of the same temperature, too long heat sealing time will also cause wrinkles. Therefore, when heat sealing, the heat sealing temperature should be set reasonably according to the different materials. In order to solve this problem, yltpackaging spent huge sums of money to introduce the intelligent heat-sealing machine from the Netherlands, which can precisely set the heat-sealing temperature and time through the control panel, and display the data on the front-end LCD. During each heat-sealing process, three sealing parameters—temperature, speed, and pressure—can be monitored at the same time. If any parameter deviates, the equipment will send out an alarm and suspend operation to ensure the heat-sealing quality.

3. Adhesive Residual Adhesive Drying Insufficient Adhesive Drying Adhesive Insufficient Drying Adhesive Insufficiently Drying Adhesive Will Decrease The Adhesive Force And The Two Substrates After Compounding Will Displace. In order to solve this problem, it is recommended to adjust the technical parameters of the adhesive properly so that the adhesive can be fully dried and the solvent residue can be reduced.

4. Cooling condition The cooling process is to shape the newly melted and sealed material at a lower temperature under a certain pressure, eliminate stress concentration, reduce weld shrinkage, and improve the flatness of the bag. Therefore, if the cooling water temperature is too high, the cooling rod pressure is not enough, the number of cooling cycles is not enough, etc., it may lead to poor cooling, which will cause the bag to wrinkle.