Polyesterfilm

Polyester film is a thin, transparent sheet made primarily from polyethylene terephthalate (PET) or other polyesters. The most common form is biaxially oriented PET (BoPET), produced by extruding PET resin into a film, then stretching it in both machine and cross directions and heat-setting to stabilize dimensions. Other polyester films include polyethylene naphthalate (PEN) and polybutylene terephthalate (PBT), which offer higher temperature ratings or different barrier properties.

Characteristics: BoPET films combine high tensile strength, excellent dimensional stability, chemical resistance, high clarity, and good electrical insulation. They are relatively resistant to moisture and have low permeability to gases, making them suitable for packaging and barrier laminates. Depending on formulation and coatings, they can withstand temperatures up to around 150–180°C for short periods.

Manufacturing: Film thickness typically ranges from about 5 to 125 micrometers. After extrusion, the film is biaxially oriented and heat-set. Surface treatments and coatings are common to improve printability, adhesion, or heat-seal performance.

Applications: Packaging films and pouches; labels and overlays; electrical insulation for capacitors and flexible circuits; laminates in graphics and solar modules; protective coverings and overlays in electronics; historical use in magnetic tapes.

Recycling and history: Polyester film was developed in the mid-20th century, with DuPont’s Mylar among the first and most influential examples. Recyclability aligns with PET streams where available, though film streams often require dedicated collection and may involve coatings or laminates that affect processing.