There are hundreds of plastics produced in industry, among which more than 60 are commonly used. Common classification methods are as follows:

According to the performance after heating:

1. Thermosetting plastics

This kind of plastic is characterized by curing and molding at a certain temperature after a certain time of heating or adding curing agent.

The cured plastic is hard, insoluble in any solvent, and cannot be softened again by heating. If the heating temperature is too high, it will melt. Common thermosetting plastics include bakelite, electric jade, decorative boards and unsaturated polyester plastics.

2. Thermoplastic

This kind of plastic is characterized by softening when heated and hardening when cooled. In general, only physical changes occur during processing to maintain its chemical nature. The resins of this kind of plastics are mostly additive. Common thermoplastics are: nitrocellulose plastic, acetate fiber plastic, polyethylene plastic, polypropylene plastic, polystyrene plastic, PVC plastic, etc. For example, our common mineral water bottles, plastic bags, etc.

By application scope:

1. General plastics

This kind of plastic mainly refers to a kind of plastic with large output, wide use and low price. They account for about 80 percent of the total plastic output. The main varieties are: polyethylene, PVC, polypropylene, polystyrene, phenolic and amino plastics.

2. Engineering plastics

Generally, it refers to plastics that can be used as structural materials in engineering technology. This kind of plastic is characterized by high mechanical strength, chemical corrosion resistance and high temperature resistance. It can replace metal or be used for other special purposes. The main varieties are: polyamide, polycarbonate, polyformaldehyde, polysulfone, ABS, polyphenyl ether, fluoroplastics, etc.

According to the degree of flammability:

1. Flammable plastics

This kind of plastic will burn violently in case of open fire and will not be extinguished easily. Such as nitrocellulose plastics, which are classified as dangerous goods.

2. Combustible plastics

This kind of plastic burns with open fire and has no self extinguishing property, but the burning speed is fast. Such as polyethylene, polypropylene, etc.

3. Refractory plastics

This kind of plastic can burn in a strong open fire and extinguish quickly after leaving the fire. Such as phenolic plastic, acetate fiber plastic, PVC plastic, etc.