[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods of polyesters, including

Polyester properties

The polyester (Polyester) is a polymer material produced by a condensation reaction between a diol and a dibasic acid, and the main component is polyethylene terephthalate (PET). Polyesters have excellent mechanical properties, including high strength, high modulus, and good toughness. These properties make polyester widely used in fibers, films and plastic products. Polyester also has good chemical resistance, light resistance and heat resistance, can remain stable in high temperature environment, not easy to degrade.

Polyester use

Polyester is widely used in textiles, packaging materials, engineering plastics and other fields. In textiles, polyester fibers are widely used in the production of clothing, home textiles and industrial fabrics due to their excellent strength, abrasion resistance and wrinkle resistance. In packaging materials, PET bottles are widely used in beverage, food and pharmaceutical packaging because of their good transparency, barrier properties and safety. In the field of engineering plastics, polyester is often used in electronic appliances, auto parts, etc., to give full play to its heat resistance and mechanical strength.

Polyester Upstream Raw Materials

Polyester production requires a variety of upstream feedstocks, two of the most critical of which are terephthalic acid (PTA) and ethylene glycol (EG). Terephthalic acid is produced by the oxidation of p-xylene (PX), and ethylene glycol is produced by the oxidation and hydration of ethylene. Some catalysts and additives may also be used in the production process to improve reaction efficiency and product quality. As basic chemical products, the market supply and price fluctuation of PX and ethylene will directly affect the production cost and market price of polyester.

Polyester Downstream Products

Polyester has a wide range of downstream products, including polyester fibers, polyester films and polyester plastics. Polyester fiber is the main raw material for the textile industry and is widely used in the production of various garments and home textiles. Polyester film is widely used in packaging, electronic display and solar panel packaging due to its good transparency and mechanical properties. Polyester plastics are commonly used in the manufacture of various types of durable consumer goods and industrial components, such as auto parts, electrical housings, etc. The diversified application of polyester products has promoted the continuous growth of its market demand.

Polyester production process

The production process of polyester mainly includes two methods: melt condensation polymerization and solid phase condensation polymerization. Melt polycondensation is the synthesis of oligomers by direct esterification or ester exchange reaction at high temperature, and then further polycondensation reaction to obtain high molecular weight polyester. Solid phase polycondensation is to further improve the molecular weight and properties of polyester by sublimation or vacuum treatment at low temperature. These two processes have their own advantages and disadvantages. Melt polycondensation is suitable for large-scale continuous production, while solid-phase polycondensation is often used to produce high-performance polyester materials.

Polyester storage methods

The storage of polyester materials needs to consider its physical and chemical properties and the use environment. Polyester fiber should be stored in a dry and ventilated environment, avoid direct sunlight and humidity to prevent aging and performance degradation. Polyester film and plastic products should be stored to avoid heavy pressure and extrusion to prevent deformation and damage. Polyester raw materials such as PET chips should be stored in a closed container to prevent moisture absorption and oxidation, which will affect processing performance. For flammable and explosive chemical raw materials, such as terephthalic acid and ethylene glycol, they should be managed in strict accordance with chemical storage specifications to ensure safety.

Polyester Industry Market Prospects

With the development of the global economy and the improvement of people's living standards, the demand for polyester materials continues to grow. Especially in the field of textile, packaging and engineering plastics, the market share of polyester is increasing due to its excellent performance and wide application prospects. With the enhancement of green environmental protection awareness, the research and application of degradable polyester and renewable resource polyester have gradually received attention, which will further promote the sustainable development of the polyester industry. In the future, with the progress of technology and the improvement of production process, the performance of polyester materials will continue to improve, and the scope of application will be more extensive.

Polyester Industry Challenges and Opportunities

The polyester industry is also facing some challenges while developing rapidly. The first is the cost pressure from raw material price fluctuations, PX and ethylene glycol.