The main ingredient of plastics is resin. Resin This term is originally secreted by animal and plant lipids and named, such as Rosin, Shellac, resin is not yet and a variety of additives mixed polymer. The resin accounts for the 40%~100% of the total plastic weight. The basic properties of plastics are mainly determined by the nature of resins, but additives also play an important role. Some plastics are basically composed of synthetic resin, do not contain or contain additives, such as plexiglass, polystyrene and so on.