The principle of woven packaging bags.

The core principle of woven packaging bags is to form a three-dimensional mesh structure through the plastic processing of polymer materials and warp and weft weaving technology, and finally make a packaging container with load-bearing and protective functions12. The following are its key principles and technical implementations:

I. Raw material physical properties basis
Polypropylene (PP) or polyethylene (PE) is selected as the main material. Its molecular chain forms a highly oriented structure after heating and stretching, giving the flat wire high tensile strength (≥50MPa) and wear resistance25.
The molecular weight distribution is controlled between 2.5-4.5 to ensure good fluidity during melt extrusion25.
II. Flat wire preparation process
‌Melt extrusion‌
The resin is heated to 185-230℃ through a twin-screw extruder and formed into a continuous film through a T-die.
‌Stretching orientation‌
A hot roller group (temperature 110-130℃) is used for 3-9 times longitudinal stretching to promote the directional arrangement of molecular chains and enhance strength23. ‌Fiber shaping‌
The diaphragm is cut into 1-3mm wide flat wires and then cooled and shaped to obtain a weaving material with a line density of 4-12tex.