Mylar® OL13 (formerly known as XM110) is a biaxially oriented polyester (OPET) film with an amorphous polyester heat seal layer. It is used as a heat sealable lidding film in packaging refrigerated and frozen foods. Mylar® OL13 is dual ovenable film which provides very strong, aggressive seals to polar substrates such as amorphous polyester (APET, also PETG), semicrystalline polyester (CPET), polyester coated paperboard, and polyvinylchloride (PVC). Mylar® OL13 does not seal to polyethylene, polypropylene, or polystyrene. DuPont Teijin Films offers another family of lidding films (RL types) for sealing to these substrates. Mylar® OL13 is similar to OL12 but has a thicker seal layer than Mylar® OL12 to give enhanced seal strength. In general, Mylar® OL13 can produce non-peeling, near "lock-up" type seals and is recommended for hot fill applications where non-peeling seals are desired. It can also be used in some "post-pasteurized" (steam sterilization) applications where the pressure balance in the package can be properly controlled (via vacuum or overpressure). Mylar® OL13 lidding films have excellent grease and oil resistance.