As the bottom gusset provides the stability and allows the pouch to stay upright, the proper choice of which style to use is important. Typically, there are 3 options:

Doyen seal

The Doyen is very common – you can recognise it from the U-shaped seal at the bottom of the front and back panel. The Doyen’s U-seal reinforces a large area of the pouch by sealing the front panel and back panel each to the bottom gusset. This provides automatic rigidity and a supported bottom, at the expense of reduced volume. The reduction in volume is small, but do keep in mind for the same size outer dimension, the Doyen will provide the least capacity. Being supported, meaning that the weight is fully supported by the sealed area, this style is best suited for light weights and small pouches.

K-Seal

The K-Seal is the intermediate style. This is characterized by a K-style seal at the corners, and a flat bottom seal across the bottom edges. Similar to the Doyen in that the bottom gusset supports the weight of the product, and provides stability and allowing the pouch to stay upright. The seal style allows the contents to spread out giving a fuller look. This style is suited for powders, granular products of medium weight.

Corner Seal

As the contents get heavier, it becomes important to reduce the force on the bottom gusset. Too heavy and you risk rupturing the pouch in handling or transport with the Doyen or K-Seal. To do this, we can introduce the corner seal style. Here there is just a simple corner seal to capture the bottom gusset. The pouch relies on the weight of the product to provide rigidity and stability. This style is unique in that the unsupported bottom allows the full weight of the product to sit on bottom gusset, which in turn actually sits directly on the shelf or box.

The above content is from http://www.weijiazhang.com/2014/01/16/stand-up-pouch-how-to-pick-a-bottom-gusset/

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