A Complete Guide to PE Square Bottom Bags (Four-Sided Bags / Bottom-Sealed Bags)

I. Basic Definition and Core Structure

PE square bottom bags are plastic bags made of polyethylene (PE) with a flat square base formed through a special heat-sealing process, also known as four-sided bags, bottom-sealed bags or open-top square bottom bags. Their core advantage is the flat base that enables self-standing without external support, combining large capacity with a neat shape.

Structural Features

• The base is rectangular or square, forming a stable supporting surface. Folded edges (accordion structure) can be added on both sides to further increase capacity and load-bearing capacity.

• The bag body is cuboid-shaped, with a neat outline after filling, facilitating stacking and display.

• Empty bags can be folded flat to save storage and transportation space, and their expanded volume is 30%-50% larger than that of flat bags of the same size.