What are the common structures of retort packaging bags?

What are the common structures of retort packaging bags?Transparent non-barrier packaging bags with two-layer structure, such asBOPET/CPPorBOPA/CPP,Its temperature resistance is135It is suitable for packing ordinary food such as dried tofu. Transparent retort packaging bags with three-layer structure, such asBOPET/BOPA/CPP,Can withstand135For some meat products such as roast chicken, ribs, etc., the retort packaging bag of this structure can be used.In addition, there is aKFilm-coated transparent barrier packaging bags, the structure of which isKBO-PET/CPPorKPA/CPP, good air resistance and dampness, but only suitable for121The high degree of cooking and sterilization treatment, and its hygienic performance needs to be further studied.Opaque retort packaging bags generally use aluminum foil as the middle layer. Because aluminum foil has very good barrier properties, and aluminum foil has good shading function, the sterilization temperature can be high or low, and the product has a long shelf life, up to2years or more. Common structures of opaque retort packaging are:BOPET/AI/CPP,BOPA/AI/CPP,BOPET/AI/BOPA/CPP,BO-PET/BOPA/AI/CPPWait. inBOPET/AI/BOPA/CPP,BOPET/BO-PA/AI/CPPConstruction can be used in puncture-resistant, reinforced, high-capacity bags and is durable135sterilization by retorting at or higher temperature. From a functional point of view, the opaque retort packaging bag with a four-layer structure can meet the requirements of all retort foods, but the price is slightly higher.