Composite packaging is a kind of composite packaging in which two or more materials are combined through one or more dry composite processes to form a certain function. Generally, it can be divided into base course, functional layer and heat seal layer. The base layer mainly plays the role of aesthetics, printing, moisture resistance, etc. Such as BOPP, BOPET, BOPA, MT, KOP, KPET, etc; The functional layer is mainly used for blocking and avoiding light, such as VMPET, AL, EVOH, PVDC, etc; The heat seal layer is in direct contact with the package, and has the functions of adaptability, permeability resistance, good heat sealing, transparency, opening date, etc., such as LDPE, LLDPE, MLLDPE, CPP, VMCPP, EVA, EAA, E-MAA, EMA, EBA, etc.