Plastic is a synthetic resin. It is reported that the first synthetic plastic in human history is called phenolic resin, which is synthesized from phenol and formaldehyde. It can also be called Baekeland plastic. Its manufacturing process is mainly divided into the following two steps: first, it is polymerized into a low molecular compound, and then it is polymerized into a high molecular compound. This plastic cannot be changed once it is molded. This is what we often call thermosetting plastics.

At present, plastics are mainly cracked from oil and natural gas into monomers, and then polymerized into high molecular polymers-plastics. We often divide plastics into two kinds, namely thermoplastics and thermosetting plastics. Thermoplastics include PVC\PP\PE\ABS\PC\PS and so on. These plastics melt after heating, and can be melted at high temperature after molding to form plastic particles again. But the formed particles can not be called new materials, but recycled materials. This kind of plastic particle contains many additives, and its quality has little influence compared with before, but its hygiene is poor.

As we all know, the application of plastics has many disadvantages. Let's take polypropylene as an example. Polypropylene, a light resin, is widely used in the field of automobile electrical appliances and medical treatment, but its light resistance, ultraviolet resistance, aging resistance and mechanical properties are poor. In the continuous research, PP plastics have broken through various shortcomings, such as grafting modification, copolymerization modification, crosslinking modification, blending modification and so on. The application scope of PP plastics is expanding and its performance is getting better and better. At present, high permeability polypropylene is very good. As we all know, polypropylene is translucent and its transparency is not very good. Therefore, in order to increase its transparency, it is necessary to use a higher transparent agent. China's PP random copolymerization is highly dependent on foreign countries. Although the third generation transparent PP material has been developed in China before, it has not been realized because of the high processing temperature and the reduced profits of the petrochemical industry. But now the fourth generation transparent PP material has been developed and used, and the temperature is obviously lower than that of the third generation, saving energy and cost. This shows that the fourth generation of transparent PP materials will be mass-produced.