Common material structure of retort pouch
There is also a transparent barrier packaging bag with K coating film. Its structure is KBOPET/RCPP or KPA/RCPP, and its gas resistance and moisture resistance are good. However, it is only suitable for cooking and sterilization treatment below 121 ℃, and its hygienic performance needs further study.
opaque cooking bags generally use aluminum foil as the intermediate layer, because the barrier property of aluminum foil is very good, at the same time, the aluminum foil has a good shading function. The sterilization temperature can be high or low, and the shelf life of the product is longer, up to more than 2 years. The common structures of opaque cooking bags are: PET/AL/RCPP, BOPA/AL/RCPP, PET/AL/BOPA/RCPP, PET/BOPA/AL/RCPP, etc. Among them, PET/AL/BOPA/RCPP and PET/BOPA/AL/RCPP structures can be used for puncture-proof, reinforced and large-capacity packaging bags, and can withstand cooking and sterilization at 135 ℃ or higher. From a functional point of view, the opaque cooking packaging bag with a four-layer structure can meet the packaging requirements of all cooking foods.