Vacuum packaging bags are made of several plastic films with different functions. Each layer of film plays a different role.
Vacuum packaging bags are divided into transparent vacuum bags and aluminium foil vacuum bags. The composite material of vacuum packaging bags is the combination of PE and nylon. The nylon has good barrier performance, can effectively block moisture and gas, and can keep vacuum for a long time. The ordinary plastic bags are only ordinary plastic. The surface of such plastic bags has air holes, No. Can be vacuum packed, even if barely packed, a long time will leak, or even just packed on the leak.
If you want to keep food freshness for a long time, it can not be achieved by vacuum, because when the oxygen concentration in the packaging bag is less than 1%, the growth and reproduction speed of microorganisms will drop sharply. When the oxygen concentration is less than 0.5%, most microorganisms will be inhibited and stop breeding. Vacuum packaging can not inhibit anaerobic bacteria. Food deterioration and color caused by reproduction and enzymatic reaction need to be combined with other auxiliary methods, such as refrigeration, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt pickling, etc.
Because different products have different requirements for packaging materials, material selection should be made according to product characteristics. Packaging film manufacturers include: whether it is easy to deteriorate, factors causing deterioration (light, water or oxygen, etc.), product shape, product surface hardness, storage conditions, sterilization temperature, etc. A good vacuum bag does not necessarily have many functions, but depends on whether it is suitable for the product.
1. Products with regular shape or soft surface: For products with regular shape or soft surface, such as meat sausage products and bean products, it is not necessary to require high mechanical strength of materials, but only to consider the barrier property of materials and the effect of sterilization temperature on materials. Therefore, for such products, OPA/PE structure is generally used in packaging bags. If high temperature sterilization is required (above 100 C), OPA/CPP structure or high temperature resistant PE can be used as heat sealing layer.
2. Products with high surface hardness, such as meat products with bones, because of their high surface hardness and rigid protuberances, they are easy to puncture bags during vacuum pumping and transportation. Therefore, the bags of these products need to have good puncture resistance and cushioning performance. The true material of PET/PA/PE or OPET/OPA/CPP can be selected. Empty bags. If the weight of the product is less than 500 g, you can try to use OPA/OPA/PE packaging bag, which has good product adaptability, better vacuum effect, and will not change the shape of the product.
3. Packaging film manufacturer's perishable products: low-temperature meat products and other products which need low-temperature sterilization do not require high strength of packaging bags, but they require excellent barrier. Therefore, pure co-extruded films, such as PA/PE/EVOH/PA/PE, can be selected, or dry-treated, such as PA/PE films. K coating material can also be used. High temperature products can use PVDC shrinkage bags or dry compound bags.
4. Higher quality products: seven-layer co-extrusion packaging, its better barrier performance, can meet the needs of 1, 2, 3 products at the same time, its use makes your products more grade, greatly prolonging the shelf life of content.