Polyester resins are a family of thermoset polymers based on ester functional groups. Polyethylene terephthalate (PET; often used in fibers) and polybutylene terephthalate (PBT; often used for molding) polymer systems are two types of common polyester materials. Commercially, the term "polyester" typically refers to PET materials. Polyester is the third-most produced plastic in the world, behind polyethylene and polypropylene.
Polyester resins are used for numerous applications, including synthetic fabrics, bottles, packaging, films, and engineered plastic.
Engineered polyester fiber to be used as reinforcement in asphalt.