What is the Difference Between Saturated and Unsaturated Polyester Resin?

The main difference between saturated and unsaturated polyester resin lies in the presence of double bonds in their main chain. Saturated polyester resins have no double bonds in their main chain, while unsaturated polyester resins have double bonds in their main chain. Here are some key differences between the two:

• Formation: Saturated polyester resins are formed by the reaction of polybasic acids and polyols, while unsaturated polyester resins are formed by the reaction of polyols with unsaturated dicarboxylic acids.
• Unsaturation: Saturated polyester resins lack unsaturated double bonds, whereas unsaturated polyester resins contain unsaturated double bonds.
• Curing: Both saturated and unsaturated polyester resins require curing to achieve their final properties. However, unsaturated polyester resins crosslink through free-radical reactions, while saturated polyester resins do not.
• Applications: Saturated polyester resins are mainly used in can coating, rolled steel, non-stick pans, ink, adhesives, PET coils, and metallic baking paints such as automotive paints. Unsaturated polyester resins are used in sheet molding compounds, bulk molding compounds, toners for laser printers, and wall panels reinforced with fiberglass.
• Fluidity: Saturated polyester resins have excellent flexibility and hardness, while unsaturated polyester resins offer better chemical resistance and strength.

Comparative Table: Saturated vs Unsaturated Polyester Resin

The main difference between saturated and unsaturated polyester resin lies in the presence of double bonds in their main chain. Here is a comparison table highlighting their differences:

Both saturated and unsaturated polyester resins are thermosetting polymers that require curing to achieve their final properties. They have various applications in industries, such as the production of sheet molding compounds, bulk molding compounds, top coatings, and more.