Stitching strength is the most important and critical purpose of FIBC. In the plastic knitting standard GB/T8946 and the national standard for composite plastics GB/T8947, the tensile load of the seam edge direction and the seam bottom direction is determined. Important factors that affect the strength of the suture are the type and example of the suture, the size of the stitch, the stitch, the standard of the crimping or folding suture to the bag edge, the hot and cold cutting methods, etc.

FIBC companies should develop internal control objectives for these influencing factors. For container bags, the national standard stipulates that the tensile strength of the main body connection needs to reach more than 67% of the basic strength, and the tensile strength of the bottom connection needs to reach more than 42% of the basic strength.

For the upper sealing of the socket cement bag, the idea is to treat it as the strength of the bottom of the seam, and for the strength of the bottom of the seam of the paper bag, it is not possible to achieve the purpose on weekdays, so the idea is changed to a paste bottom bag. For laminated cold-cut bags, it is advisable to use the crimping treatment, as the stitches on the cold-cut edges can be torn out of the warp along with the weft. For the woven bag that has no need for strength, the upper mouth is locked for one week, the stitch distance can be dense, and the thread can be thin.