PET (Polyethylenterephthalat)

Polyethylene terephthalate (PET) is a thermoplastic material from the polyester family. It is produced by polycondensation of terephthalic acid (or dimethyl terephthalate) with ethylene glycol and is one of the most important plastics worldwide. PET is used on a large scale in both the packaging industry and the textile sector and is characterised by a combination of high strength, transparency and good processability.

With a density of approx. 1.38 g/cm³, PET has a significantly higher density than polyethylene (PE) and polypropylene (PP), but remains considerably lighter than glass. This makes it a stable and at the same time lighter alternative to glass in many areas. Its linear, partially crystalline molecular structure ensures high breaking strength, good dimensional stability and excellent barrier properties against gases (e.g. CO₂, O₂) and liquids.

Key properties of PET:
High mechanical strength and impact resistance.
Very good shape and dimensional stability, even at changing temperatures.
Excellent transparency and gloss, making it suitable for visually appealing packaging.
Good barrier properties against gases and moisture – crucial for beverage packaging.
Good heat resistance (up to approx. 70 °C, even higher for modified PET – e.g. PET-G or crystalline PET).
High chemical resistance to oils, fats and diluted acids, less resistant to strong alkalis.
Very recyclable – PET is collected, processed and reused in large quantities worldwide.

Typical areas of application:
Packaging: beverage bottles, food containers, films.
Textiles: manufacture of polyester fibres for clothing, home textiles, non-woven fabrics.
Technical applications: plastic parts in the automotive sector, insulating materials, films for electrical applications.
Medicine and laboratory: blister packaging, sterile containers.

In the recycling cycle, PET is usually marked with the symbol ‘1’ in the recycling triangle. Due to its good recycling properties (mechanical or chemical) and the possibility of recycling it into new bottles or fibres, PET is considered a key material for sustainable packaging solutions.