Polyester

PET contains no BPA and no phthalate plasticisers. BPA belongs to polycarbonate and to epoxy can linings; the phthalates people worry about belong to flexible PVC. What PET does carry is antimony, the catalyst used to make it: total antimony in the plastic runs on the order of 100 to 400 mg/kg, but very little of it moves. Measured levels in bottled drinks sit within drinking-water limits - fresh juices in one review ranged 0.17 to 1.45 µg/L against an EU drinking-water maximum of 5 µg/L - and the EU sets a specific migration limit of 0.04 mg/kg for antimony in food contact. The variable that actually changes those numbers is temperature, not time on the shelf. Worn against skin, polyester itself has no established leaching route; the chemistry questions on a garment are about disperse dyes and applied anti-odour or water-repellent finishes rather than the fibre.

Antimony migration in PET is a heat story rather than an age story. In storage trials there was no significant migration at 4 °C or 20 °C over 30 days; at 40 °C levels rose slightly, to roughly 0.55-0.92 µg/L by day 30, and at 60 °C they reached 0.95-2.71 µg/L within 21 days. Those figures are still under the drinking-water limit, but they point at the scenario that matters: a case of bottled water left in a hot car or a garage, or a bottle refilled with hot liquid, not the bottle as sold. As a fabric, polyester's practical limits are a hot iron and a hot dryer, which glaze and shrink it - and in a stretch blend it is the elastane, not the polyester, that fails first.

On packaging: a 1 in the triangle, usually with a small moulding pip in the centre of a blow-moulded bottle base. Unmarked, PET is glass-clear, rings rather than thuds, and sinks in water, which separates it from polypropylene and HDPE, both of which float. On a garment, read the fibre-content label - polyester, PES, PET and "recycled polyester" all mean this polymer, and a "microfibre" cleaning cloth is normally a polyester and polyamide split fibre. The kitchen lookalike is copolyester (PETG, Tritan), which is also clear and also sinks but is a different resin, usually coded 7. If a brand says only "BPA-free clear plastic", ask which of PET, PETG or Tritan it is.

Polyester's defining maintenance issue is fibre shedding in the wash. One study measured 124 to 308 mg of microfibres released per kg of fabric per cycle, roughly 0.6 to 1.5 million fibres from a single load. Another, across 37 consumer textiles, found mechanically treated polyester - fleeces and jerseys - shed six times more than woven nylon, 161 against 27 mg per kg per wash. The honest comparison is that cotton and wool shed a similar mass in that same study (165 mg/kg); the difference is that polyester fibres persist afterwards. Washing full loads, cool, and less often reduces shedding, and an in-line laundry filter retained up to 90% of polyester fibres in testing.

PET bottles are the most-recycled plastic in the US and still only reached 29.1% in 2018, against 8.7% for plastics overall. Polyester clothing is effectively not recycled: rPET fibre is made from bottles, which moves PET out of the closed bottle-to-bottle loop rather than creating a textile loop, and any elastane in the blend blocks fibre-to-fibre recycling outright. PET does not biodegrade.