Bundle bags are different from ordinary plastic woven bags. Because their carrying capacity is much larger than that of ordinary packaging, the sewing of their various parts is also very important. Unlike ordinary plastic bags, which can be simply heat-sealed, they need to go through multiple processes and be combined with other parts.
This is the most critical goal of bulk bags. In the plastic woven standard GB/T8946 and the national standard GB/T8947 for composite plastics, the tensile loads in the seam edge and seam bottom are clearly defined. The main factors affecting the sewing strength are the variety and type of sutures, the size of the needle gauge, the stitches, the size of the hem or folded sutures to the bag edge, the hot cutting and cold cutting methods, etc.
Generally speaking, bulk bag production companies should formulate internal control targets for these influencing factors. Regarding bulk bags, the national standard stipulates that the tensile strength of the main joint must reach more than 67% of the basic strength, and the tensile strength of the bottom joint must reach more than 42% of the basic strength. For the upper seal of the plug-in cement bag, it is recommended to treat it as the strength treatment of the bottom of the seam. The strength of the bottom of the paper bag is usually not up to the target, so it is recommended to change it to a paste bottom bag. For the cold-cut bag with laminated film, it is recommended to use the curling treatment because the suture of the cold-cut edge may be torn out of the warp together with the weft. For the woven bag without strength requirements, the upper edge is locked for one week, the stitch length can be dense, and the thread can be thin.