The back sealing bag is also called back sealing packaging bag. It is formed by folding the two sides of the ordinary flat mouth bag into the inside of the bag, and folding the originally elliptical opening bag into a rectangular opening. After folding, the sides of the bag are like the leaves of the air outlet, but they are closed, so the bag is named as the organ bag.

Compared with other packaging forms, the back sealed bag has no sealing edge on both sides of the bag body, so the pattern on the front of the package is complete and beautiful. At the same time, in the layout design, the bag pattern can be designed as a whole to keep the picture consistent. As the seal is on the back, both sides of the bag can bear more pressure, reducing the possibility of package damage. In addition, the total length of the back sealing of the same size packaging bag is the smallest, which also reduces the probability of sealing cracking in a certain sense. Generally all kinds of vegetables, seafood, meat and other nutritional pills, leisure food, noodles, daily chemical toys, bagged dairy products, etc. are packaged in this form.

From the material point of view, there is no difference between back sealing bag and general heat sealing bag. In addition, composite packaging such as aluminum plastic, aluminum paper and so on are also widely used in the form of modified packaging. The most common packaging is milk packaging in bags and melon seeds packaging in large bags.

The difficulties in the manufacture and packaging of back sealing bags lie in the heat sealing T-shaped mouth and the heat sealing temperature at the "T" shaped mouth. It is not easy to master the heat sealing temperature. If the temperature is too high, other parts will wrinkle; if the temperature is too low, the "T" shaped mouth cannot be well sealed.

In the design of back sealing bag, the front pattern should be slightly larger than the finished product size to prevent the front pattern from being too small after the bag is made. At the same time, it should be considered whether there is no seam at the top, bottom, left and right, and whether the light spot location is set to meet the needs of cutting and bag making. In addition, it should be noted whether transparent or the same color connection is needed between the finished patterns of the unit.