The main raw materials of PET are ethylene glycol (EG) and terephthalic acid (PTA), which are widely used as fibers, which can be divided into two categories: non-engineering plastics and engineering plastics.

PET has excellent properties (heat resistance, chemical resistance, toughness, electrical insulation, safety, etc.) and is cheap, so it is widely used as fibers, films, engineering plastics, polyester bottles, etc.

Internationally, the industrialized products of polyester thermoplastics have the following six aspects (the ones that have been industrialized are sold as commodities).

(1) Liquid crystal polymer

(2) Polybutylene terephthalate (PBT)

(3) Polyethylene naphthalate (PEN)

(4) Polyethylene terephthalate engineering grade PET

(5) Standard grade PET of polyethylene terephthalate

(6) Polyethylene terephthalate recycled PET (including blends and 100% recycled materials)

Non-engineering plastic grades are mainly used for fibers, beverage bottles, films, sheets, bake-resistant food containers, etc. Engineering plastic grade PET is resistant to organic solvents and has good weather resistance. The disadvantage is that the crystallization rate is slow, the molding process is difficult, the molding temperature is high, the production cycle is long, and the impact performance is poor. Generally, its processability and physical properties are improved by methods such as reinforcement, filling, and blending. The glass fiber reinforcement effect is obvious, and the rigidity, heat resistance, chemical resistance, electrical properties and weather resistance of the resin are improved.

The disadvantages of slow crystallization speed are improved by means of adding nucleating agents and crystallization accelerators. Adding flame retardants and flame retardant dripping agents can improve the flame retardancy and self-extinguishing properties of PET.