Analyze of composite film packing bag

Generally the plastic packaging materials for puffed food packing bag is composite membrane. It is consit of printing layer,aluminium block and combined heat sealing layer (domestic common structure including BOPP/VMPET/PE, BOPP/VMPET/CPP, BOPP/VMPET/EX - PE/PE, etc.). The aluminum layer will no touch food directly. Usually the  in layer directing contact with food is some more safer plastic.  The product of formal enterprise is certain to pass safety authentication, ability can be assured to eat. Generally this kind of product itself is relatively fat. Food is easy to be oxidized, such as the halla flavour of oil is oxidized to be changed. In order to guarantee the shelf life of the product, it normally have a high requests for the barrier property of packaging material. Aluminum is widely used in food packaging, which is recognized as both malleable and obstructive.