Reasons and control methods for easy breakage of bellows packaging bags

Currently, many customers are continuously improving the automation process of production, and the requirements for packaging bag manufacturers will become increasingly stringent. There are two common production processes for bellows bags: one is a center-sealed bellows bag, and the other is a four-side-sealed bellows bag. Both processes have a common process control point that needs attention: the bellows position. At the same time, many other types of bellows bags are derived, such as bottom bellows bags and eight-side-sealed bellows bags.

Center-sealed bellows bag

Four-side-sealed bellows bag

Bottom bellows bag

Eight-side-sealed bellows bag

Among many types of packaging bags, the center-sealed bellows bag has a larger internal space than other three-side-sealed bag types and can save costs, so it is very popular with customers.

Bellows bags are generally used in the packaging of clothing, hardware, electronics, food, and daily necessities, and their applications are very wide. For packaging with contents under 300g, the production of bellows bags generally does not have any major problems, whether it is the materials used or the production process, companies have mature applications. However, for packages over 300g, especially for powdery or small granular contents, it is a greater test for flexible packaging manufacturers. This type of content is also a considerable test for customers' automatic packaging equipment.

I. Common problems with bellows position

There is a stepped position at the junction of the bellows position and the horizontal sealing position. That is, there are only two layers of material heat-sealed at the horizontal sealing position on both sides of the bellows, while the horizontal sealing edge of the bellows position has four layers of film that need to be heat-sealed. Therefore, a stepped junction sealing edge will appear at this position. Since the heat-sealing mold is basically on a horizontal plane, the bag often breaks from here.

For the problem of easy bag breakage at the junction of the horizontal seal and the bellows, Shunxingyuan Packaging, a professional flexible packaging manufacturer, has come up with many solutions to effectively reduce the breakage rate of bellows bags.

II. Common solutions

1. Improve raw and auxiliary materials

This improvement mainly enhances the physical properties of the raw materials, such as selecting materials with anti-cracking, tensile, wrinkle resistance, increased flexibility, increased toughness, and improved physical and mechanical properties for the inner layer substrate to reduce the probability of the bellows line being damaged during production. Or improve it by increasing the material thickness. At the same time, adhesives with better toughness can be used to enhance wrinkle resistance and improve the packaging's resistance to breakage and crumpling.

2. Improve material structure

Bellows bags generally choose structures such as BOPP/CPP, PET/PE, BOPP/PE, PA/PE, PET/AL/PE, PA/AL/PE, PET/PA/PE. When a certain structure is relatively weak, materials with better physical properties can be used as substitutes, or the number of structural layers can be increased to improve the overall strength of the bag. Considering the mechanical properties such as fabric bending resistance and mechanical tensile properties, NY is superior to PET, and PET is superior to BOPP. Of course, if NY is used to replace PET, the cost will definitely increase. We can also improve the material properties of the bellows bag by increasing the number of structural layers. This is also a good method, but the cost will increase significantly. When increasing the number of material layers, be very careful and carefully evaluate the changes in performance brought about by the added material.