What is saturated polyester resin？

Saturated polyester resin, as an important branch of polyester resin, is a polymer compound prepared by condensation reaction of diacids and diols. Its molecular structure does not contain unsaturated double bonds, which endows saturated polyester resin with excellent stability and weather resistance. According to different application fields and performance, saturated polyester resins are mainly divided into two categories: thermoplastic and thermosetting. Thermoplastic saturated polyester resin is mainly used in the production of plastic products, while thermosetting saturated polyester resin is widely used in fields such as coatings and adhesives.

What is unsaturated polyester resin？

Unsaturated polyester resin (UPR) is generally a linear polymer compound with ester and unsaturated double bonds formed by the condensation of unsaturated dicarboxylic acids and diols or saturated dicarboxylic acids and unsaturated diols. During the preparation process, this resin is usually subjected to polyester polymerization reaction at a temperature of 190-220 ℃ until the expected acid value or viscosity is achieved. Subsequently, a certain amount of vinyl monomer is added while hot to form a viscous liquid. This polymer solution can undergo free radical copolymerization under the action of initiators, light or heat, and crosslink to form thermosetting polymer products. Unsaturated polyester resin has been widely used in various industries due to its excellent corrosion resistance, weather resistance, and mechanical strength.

What is the difference between saturated polyester resin and unsaturated polyester resin？

1.molecular structure

Saturated polyester resin: The molecular structure does not contain unsaturated double bonds, so its stability and weather resistance are good.

Unsaturated polyester resin: The molecular structure contains unsaturated double bonds, allowing it to undergo free radical copolymerization under the action of initiators, achieving cross-linking and curing.

2.Physical and chemical properties

Saturated polyester resin: It has excellent weather resistance, chemical corrosion resistance, mechanical strength, and electrical insulation properties, and is suitable for long-term exposure to harsh environments.

Unsaturated polyester resin: It also has good corrosion resistance, weather resistance, and mechanical strength, but its hardening process is fast, and it is commonly used in situations that require rapid curing.

3.Application area

Saturated polyester resin: mainly used in the production of coil coatings (such as topcoat, primer, and back coat), inks, heat coated coils, insulation materials, intermediate and high-grade printing adhesives, and insulation materials.

Unsaturated polyester resin: widely used in chemical anti-corrosion equipment, pipelines, storage tanks, power transformers, insulators, electronic component packaging and other fields. Its rapid hardening characteristics make it particularly suitable for mold manufacturing, compression molding, extrusion molding and other processes.

4.Curing Method

Saturated polyester resin: It is mainly cured through thermal curing or chemical curing, and the curing process is relatively slow.

Unsaturated polyester resin: It can be cured by heat curing, by adding initiators at room temperature, or even by irradiation such as ultraviolet light and electron beam, with a fast curing speed.

What are the characteristics of saturated polyester resin and unsaturated polyester resin?

Characteristics of saturated polyester resin

1.Stability and weather resistance: Due to the absence of double bonds in the molecule, saturated polyester resin has excellent stability and weather resistance, making it suitable for long-term outdoor use.

2.Processing performance: Thermoplastic saturated polyester resin has good processing formability and is easy to process into various plastic products.

3.Economy: Partially saturated polyester resin varieties have high cost-effectiveness and are suitable for general coil coating requirements.

Characteristics of unsaturated polyester resin:

1.Rapid hardening: Unsaturated polyester resin can quickly cure under the action of initiators, improving production efficiency.

2.Corrosion resistance: Its excellent corrosion resistance makes it the preferred material in the field of chemical anti-corrosion.

3.Diversified applications: Not only used in traditional anti-corrosion and insulation fields, but also widely applied in multiple industries such as electronic packaging and mold manufacturing.

Conclusion：

Saturated polyester resin and unsaturated polyester resin, as two important branches of polyester resin, have significant differences in molecular structure, physical and chemical properties, application fields, and curing methods. Saturated polyester resin occupies an important position in the fields of coatings, insulation materials, etc. due to its excellent stability and weather resistance; Unsaturated polyester resin, on the other hand, plays an irreplaceable role in various industries such as chemical anti-corrosion, electrical and electronics due to its rapid hardening characteristics and wide applicability. With the advancement of technology and changes in market demand, both are constantly optimizing and innovating in their respective fields, jointly promoting the sustainable development of the polyester resin industry. In the future, with the increasing requirements for environmental protection and sustainability, the production and application of saturated polyester resin and unsaturated polyester resin will further move towards high performance, low cost, and green environmental protection.