Composite plastic bags include center-sealed bags, three-side-sealed bags, piano-sealed bags, stand-up bags, four-side-sealed bags, special-shaped bags, composite roll films, and active packaging roll films; they are also divided into container bags, general transport bags, Small bags, etc. Composite packaging is two or more materials that are combined through one or more dry composite processes to form composite packaging with certain functions.

Generally, it can be divided into base layer, functional layer and heat sealing layer. The base layer mainly plays the role of beauty, printing, and moisture resistance. Such as BOPP, BOPET, BOPA, MT, KOP, KPET, etc.; the functional layer mainly plays the role of barrier and light protection, such as VMPET, AL, EVOH, PVDC, etc.; the heat-sealing layer is in direct contact with the packaged items, and it is adaptable and resistant to penetration Sex, outstanding heat sealability.

As well as transparency, openness and other functions, such as LDPE, LLDPE, MLLDPE, CPP, VMCPP, EVA, EAA, E-MAA, EMA, EBA, etc. Composite flexible packaging materials can only be used after being made into various packaging bags. There are two ways to make bags. One is that the packaging manufacturer uses roll film to fill on the automatic packaging machine, and then molds and packs it into various packaging bags; the other is because the bag-making machine makes various packaging bags and then fills them with the contents. .

Due to the precise operation of professional bag making, beautiful bag shape, great changes in bag making, and many bag shapes, in many cases, bags are made first. The main types of bags are: three-side sealed bag (closed palm bag), back-sealed bag, folded side (organ bag), stand-up bag, etc., a large-volume transport packaging bag with a packing weight of more than 1 ton.