Polyethylene terephthalates (PET) for films and sheets

In addition to saturated thermoplastic polyesters, only polyethylene terephthalates (PET) are used in the manufacture of films and sheets. Two product families are concerned by this application:

• homopolymers of terephthalic acid and ethylene glycol (PET);

• copolymers made from two acids with one diol, or from a single acid with two diols.

Extruded or thermoformed films of various thicknesses from these polymers have excellent thermomechanical, optical and electrical properties, as well as good chemical resistance. They can also be metallized.

These films, whether stretch-oriented or non-oriented, have found numerous applications in the audiovisual, packaging, electrical and electronics sectors, etc.

In industry, the designations APETP (or APET) and CPETP (or CPET) are often used, referring to the amorphous (A...) or crystalline (C...) state of the homopolymer in question, and PETG for the glycol-modified copolymer.