Polyester/Vinyl Ester Resins

Polyester and vinyl ester resins are the most commonly used matrix resins to create composite parts.

Polyester resins, also known as Unsaturated Polyester Resins (UPR), combined with fiberglass reinforcements have been the building blocks of the composites industry for decades. These formulations provide low cost, ease of handling, quick cure, and high strength to create a wide variety of composite parts in countless applications. They are ideal for open molding as well as closed molding processes such as vacuum infusion processing, resin transfer molding, filament winding, compression molding and pultrusion. Polyester resin is also the primary resin matrix used in compression molding, bulk molding compounds (BMC) and sheet molding compounds (SMC), and in the pultrusion process.

There are a wide variety of polyester resin formulations available for specific applications. These include:

• Ortohphthalic (Ortho) based general purpose resin
• Isophthalic (Iso) based resin with higher heat distortion and improved corrosion resistance
• Dicyclopentadiene (DCPD) based resin for low shrinkage and improved cosmetics
• Specialty resins for fire performance, food service, or specific corrosion resistance

Vinyl ester resins (VE) are a polyester backbone molecule with an epoxy component. Vinyl ester formulations provide enhanced corrosion resistance and have a wide range of available strength, heat distortion, and shrinkage characteristics.