Polyester film is a high-performance film made from polyethylene terephthalate (PET) resin. The Polyethylene Terephthalate (PET) resin is made from Ethylene Glycol and dimethyl terephthalate (DMT). The PET resin used is of a similar intrinsic viscosity (IV) to fiber grade resin, used to produce polyester fibers, but has a higher purity. PET resin is made in special grades for specific film types and often contains slip modifiers.