Views:2 Author:Site Editor Publish Time: 2018-11-09 Origin:Site
Stand up pouches are a kind of flexible packaging belt with horizontal support structure at the bottom. It can stand on its own without any support. Self-support bag is a relatively new form of packaging and then upgrade the product grade, enhance the visual effect of the shelf, portable and convenient to use, insurance and airtightness and many other aspects of the advantage. As a result, it also has some disadvantages about high price, accounting for a large shelf area, blowing and weeping，Poor evenness and symmetry
These bags are generally wholesale at 5 cents a piece, much more expensive than ordinary plastic bags. Most of their prices are sold on a per-unit basis, while the price of plastic bags is sold by weight. Vertical bags are a little more expensive than plastic bags because they require a certain amount of craftsmanship and expensive production equipment
2.accounting for a large shelf area
These bags are generally wholesale at 5 cents a piece, much more expensive than ordinary plastic bags. Most of their prices are sold on a per-unit basis, while the price of plastic bags is sold by weight. Vertical bags. are a little more expensive than plastic bags because they require a certain amount of craftsmanship and expensive production equipment
3.blowing and weeping
The main reasons for leakage and leakage of upright bags are two aspects of composite material selection and hot air strength.
（1） Composite material selection
Material selection of vertical bags is very important for leak prevention. In terms of three-layer structure, the bonding strength between printing film and intermediate anode barrier, barrier layer and heat seal layer is concentrated. In addition, the choice of materials such as ink, adhesives and various organic solvents is also important.
（2） Thermal sealing strength
Heat seal strength is also one of the important factors that affect the leakage and leakage of upright bags. During sealing, attention must be paid to the control and adjustment of heat sealing temperature, heat sealing pressure and heat sealing time. Among them, heat sealing temperature is the main factor. Different kinds of plastic film have different sealing temperatures，The heat sealing pressure should not be too high and the heat sealing time should not be too long, so as to avoid the degradation of macromolecules and reduce the sealing strength. The four-layer seals at the bottom of vertical bags are the most critical parts. Therefore, attention must be paid to the heat sealing strength test when sampling.
4. Poor evenness and symmetry
Smoothness is one of the indexes that measure the appearance quality of the packaging bags. In addition to material factors: the flatness of vertical bags is also related to heat sealing temperature, heat sealing pressure, hot cutting time, cooling effect and other factors. Symmetry not only affects the appearance of upright bags, but also affects the anti leakage performance of the whole bag.
In summary，Compared with ordinary bags, there are still some shortcomings in upright bags. Therefore, when using vertical bags, attention should be paid to check whether the bags leak air in order to prevent products from deteriorating when stored in vacuum, and to widen the shelves when placing products packed in vertical bags. When transferring bags, we should pay attention to its smoothness, keep the appearance of products and attract customers.