Vacuum packaging bags are also known as decompression packaging. The important link is to remove oxygen, prevent food from spoiling, and maintain the nutritional value of food. What are the types of vacuum bags? Vacuum packaging bags are used very frequently in daily life, and households use vacuum packaging bags to package food to achieve the purpose of extending the shelf life. The material of the vacuum bag directly affects the preservation performance. Next, let’s take a look at the material and characteristics. Commonly used food-grade vacuum packaging materials are as follows: 1. Polyester vacuum bags: Polyester is a general term for polymers obtained by polycondensation of polyols and polyacids. Mainly refers to polyethylene terephthalate (PET), polyester (PET) vacuum bag. It is a colorless, transparent and glossy vacuum bag. It is made of polyethylene terephthalate. It is a vacuum bag material made of thick sheets by extrusion and then biaxially stretched. Excellent mechanical properties, high rigidity, hardness and toughness, puncture resistance, friction resistance, high temperature and low temperature resistance, chemical resistance, oil resistance, air tightness and good fragrance retention, is a commonly used barrier composite vacuum bag substrate one. It is commonly used as the outer layer material of retort packaging, and has good printing performance. Food bag 2. Nylon vacuum bag: Nylon (PA) vacuum bag is a very tough vacuum bag with good transparency, good luster, high tensile strength and tensile strength, and good heat resistance. It is suitable for packaging hard items, such as greasy food, meat products, fried food, vacuum Packaged food, retort food, etc. On the basis of nylon vacuum bags, higher performance nylon composite bags and multi-layer co-extrusion vacuum bags can be derived. The main components of nylon composite bags are PET/PE, PVC/PE, NY/PVDC, PE/PVDC, PP/PVDC. The main difference is that the composite bags are generally composed of substrates, lamination adhesives, barrier materials, and heat-sealing materials in terms of technology. , printing and protective layer coatings. The main component of the multi-layer co-extrusion vacuum bag is nylon, which is composed of PA, EVOH and PE, PP, TIE and other resins, and adopts a symmetrical or asymmetrical combined structure. Due to the addition of PA and EVOH, not only the barrier properties of the multilayer film to oxygen and fragrance, the composite peel strength, the environmental resistance and the fresh-keeping storage period are greatly improved. It has the characteristics of no pollution, high barrier, strong function, low cost, small capacity ratio, high strength, flexible structure, etc. It makes the production process of food packaging materials pollution-free. Three, PE vacuum bag: Polyethylene (polyethylene, PE for short) is a thermoplastic resin obtained by polymerization of ethylene. The transparency is lower than that of nylon, the hand feel is stiff, the sound is brittle, and it has excellent gas resistance, oil resistance and fragrance retention. Not suitable for high temperature and refrigeration use, the price is cheaper than nylon. Generally used for ordinary vacuum bag materials without special requirements. Four, aluminum foil vacuum bag: aluminum-plastic composite vacuum packaging bag (PET/AL/PE or PET/NY/AL/PE or PET/NY/AL/CPP), the main component is aluminum foil, opaque, silvery white, It has the characteristics of anti-gloss, good barrier property, heat-sealing property, optical shading property, high temperature resistance, low temperature resistance, oil resistance, fragrance retention; non-toxic and tasteless; softness and so on. It is suitable for moisture-proof, light-proof and vacuum packaging of large-scale precision machinery and equipment, chemical raw materials, and pharmaceutical intermediates. The four-layer structure is mostly used, which has good water and oxygen barrier functions. Aluminum foil vacuum bags are widely used in food, electronics, chemical and other industries. Since the raw material of aluminum foil itself is relatively expensive, the cost of vacuum will be relatively high. Composite packaging bags, vacuum packaging must be frozen at -40 degrees, and then stored at -18 degrees to store for about three months. If preservatives are added to cooked food products, they can be stored for 15 days in vacuum packaging and 30 days in low temperature storage. After a few days, both the taste and the taste will be much worse. Some tea packaging bags will have a shelf life of 45 days to 60 days written on the packaging bags. Large supermarkets have regulations. If the shelf life exceeds one-third of the total, it cannot be received, and if it exceeds one-half, it will be cleared. Second return. What kind of cooked food is the shelf life score of vacuum-packed food. 5-15 days if it’s simple cooking, 1-3 months if it’s smoked, fried, fried chili chicken or the like. Braised roast meat can generally be stored for 5-15 days, and braised products can generally be stored for 10-20 days. Packaging methods such as vacuum packaging and nitrogen-filled packaging cannot play a role in sterilization. Because cooked food has a lot of moisture and is rich in nutrients, it is easy to breed bacteria, and sometimes the speed of spoilage of some foods is accelerated after vacuum packaging. If vacuum packaging is used, but it is not sterilized, the effect on quality assurance is very weak, and bacteria will still spoil the food, so the purpose of quality assurance cannot be achieved. Vacuum packaging itself does not sterilize, but it can support high-temperature sterilization after vacuum packaging. That is to say, vacuum packaging bags participate in the high-temperature sterilization process of food. Therefore, after sterilization, due to the vacuum conditions of vacuum packaging, the food is sterilized. Shelf life is extended. After sterilization, the shelf life of vacuum-packed meat food at room temperature is about 20 days, and it will be appropriately extended if it is refrigerated. If not sterilized after vacuum packaging, the shelf life of cooked food will hardly be extended. Aluminum foil bag, plastic packaging bag