==Manufacturing ==
PET is made from ethylene glycol and terephthalic acid. From that polymer, fibers are made by a [[melt-spinning]] process, mostly in a continuous line with both the polymerization and melt spinning. The high speed at the [[spinning]] process requires the use of lubricants (spinning oils). They are commonly made of mineral oil with the addition of surfactants to facilitate the washing-out process when dyeing. In order to avoid that the fiber turns glassy (shiny) a matting agent in the form of titanium oxidedioxide, or silicates are added, also optical brighteners are added. For the polymerization one needs small amounts of metal catalysts and at the end of polymerization one also needs a “catalyst-poison” in order to get the correct chain lengths.
== Potential impacts ==