Square bottom bag is also called sewn open mouth bag or single-end paste bottom bag. The bottom of the bag is aligned, folded and glued. It is rectangular after filling. A firm bottom paper can be attached to increase the strength. The flat bottom will stand stable and not easy to leak during filling or filling. It has the characteristics of good environmental protection, high firmness, stable stacking and easy identification. It is mainly used for powder and granular products in industries such as edible powder and additives, chemical powder, feed, plastics, etc., and is widely used in the packaging industry.