The main component of plastic packaging boxes is synthetic resin. The term resin originally came from lipids secreted by animals and plants, such as rosin, shellac and so on. At present, resin refers to polymers that have not been mixed with various additives. Resin accounts for 40%-100% of the total weight of plastics. The basic properties of plastic packaging boxes mainly depend on the nature of resins, but additives also play an important role. Some plastic packaging boxes are basically composed of synthetic resins, without or without additives, such as plexiglass, polystyrene and so on.

There are basically two types of polymer structures in plastic packaging boxes:

The first is linear structure, which is called linear polymer.

The second is the body structure, which is called bulk polymer compounds. Some polymers have branched chains, called branched polymers, which belong to linear structure. Although some polymers have crosslinks among molecules, they have less crosslinks. They are called reticular structures and belong to body structure.

Plastic packaging boxes can be divided into two categories: thermosetting and thermoplasticity. The former can not be re-moulded and used, while the latter can be repeatedly produced. The so-called plastic packaging box, in fact, is one of the synthetic resins. Its shape is similar to that of pine resin in natural resins, but it is called plastic packaging box because it is synthesized by chemical means.