What Is Polyester?

How is polyester made?

The most important polyester, polyethylene terephthalate (PET), is made by reacting ethylene glycol with terephthalic acid and spinning the resulting molten polymer directly into fibres. The reaction joins the two chemicals with ester links and gives off water as a by-product. A large ring structure in each repeating unit gives PET its stiffness and strength, especially when the long molecules are stretched into alignment.

The same polymer is blow-moulded into drinks bottles. That shared chemistry is why recycled polyester can be made from bottles, as the sustainability section below explains.

Who invented PET polyester?

PET was first prepared in England by J. Rex Whinfield and James T. Dickson of the Calico Printers Association. According to Lancashire County Council’s museum service, the first fibre of this polyester was made at the association’s Broad Oak Printworks in Lancashire in 1941, and Whinfield named it Terylene. The discovery was not announced at once because of the war, but a patent was registered.

By 1943 Imperial Chemical Industries (ICI) had a development agreement with the Ministry of Supply. Once the patent was accepted after the war, DuPont acquired the US rights, and in 1947 the Calico Printers Association assigned its worldwide patents and rights outside the USA to ICI. Britannica dates commercial production to 1953 for DuPont’s Dacron and 1954 for ICI’s Terylene.

What are the properties of polyester?

Polyester is strong, resists wrinkling and holds heat-set pleats and creases, but it absorbs body oils, builds up static and may pill. The University of Georgia Cooperative Extension lists both sides:

Pleats set into polyester with heat, such as accordion pleats, are retained, and the extension service rates its wash-and-wear performance as superior. Polyester is also made into fibre filling for insulated clothing, according to Britannica.

Polyester is often blended with cotton, wool, rayon, acetate and linen. Britannica notes its use in durable-press blends with rayon, wool and cotton, because it gives fabrics excellent resistance to wrinkling.

Are there different kinds of polyester?

Yes: PET is the polyester sold under trade names such as Dacron and Terylene, but US labelling law recognises a few variants, and both US and EU law give some related fibres names of their own.

• Triexta: under US rules, a polyester whose glycol is at least 90 mole per cent 1,3-propanediol may be called triexta.
• Elasterell-p: a US name for a stretch fibre formed from two or more chemically distinct polymers in which ester groups dominate, and which reverts rapidly to its length after being stretched at least 100%. The EU uses a comparable name, elastomultiester, for a fibre formed from two or more chemically distinct linear macromolecules.
• PLA (polylactide): a fibre made of lactic acid ester units. Both the US and the EU give it a separate name, so it is not labelled polyester.

Polyester is also a different fibre from nylon, acrylic and spandex, each of which has its own generic name under US law; in the EU, nylon is listed as “polyamide or nylon” and spandex as “elastane”.

How does polyester appear on a clothing label?

Polyester appears on the label by its legal name, “polyester”, with its percentage by weight, unless it is a very small share that may be grouped as “other fibres”; a trade name alone is not enough in the US. The definitions differ slightly. US law defines polyester as a long-chain synthetic polymer with at least 85% by weight of an ester of a substituted aromatic carboxylic acid. EU law requires at least 85% by mass of an ester of a diol and terephthalic acid.

Under US rules

• Fibres are listed by generic name and percentage by weight, in order of predominance.
• A fibre under 5% of the total weight is normally grouped as “other fiber”, with exceptions that include fibres of clearly established functional significance.
• If a trademark such as Dacron is used, the generic name must appear in immediate conjunction with it.
• The label must also give the manufacturer’s name or registered identification number (RN) and the country where the product was processed or made.

Under EU rules

• Only the fibre names in Annex I of Regulation (EU) No 1007/2011 may be used, so “polycotton” is not a legal fibre name.
• All fibres are listed with their percentage by weight, in descending order.
• One fibre of up to 5%, or several totalling up to 15%, may be grouped as “other fibres” when they cannot easily be stated at manufacture.
• “100%”, “pure” or “all” is reserved for products made of one fibre, though up to 2% of technically unavoidable extraneous fibre is tolerated.
• The label must be in the official language or languages of the member state where the product is sold, unless that state provides otherwise.

What the percentage tells you

The percentage tells you how much of the cloth, by weight, is polyester, and the first fibre listed is always the largest share. Fabrics containing polyester are easy to care for and wrinkle-resistant in wear, according to the University of Georgia Cooperative Extension, but polyester itself absorbs body oils and builds up static.

How do you tell good polyester from poor polyester?

Judge polyester by its label, its surface and, on second-hand pieces, the signs of oil, odour and heat damage, because those are its known weak points. These checks take a minute:

1. Read the sewn-in label. Look for the word “polyester” and a percentage. In the US, if a trademark such as Dacron appears with the required fibre information, the generic name must appear right next to it.
2. Look at the rub points. Check underarms, cuffs and the seat for small balls of fibre and clinging lint; polyester may pill and attract lint.
3. Check pleats and creases. On a pleated polyester piece, the folds should be crisp along their whole length, since the fibre retains heat-set pleats and creases.
4. Smell and inspect collars and underarms. On vintage and resale pieces, marks and a lingering smell in these areas can point to absorbed body oils and perspiration odour, both known polyester limitations.
5. Look for shine or hardened patches. Polyester melts if it gets too hot, so check second-hand pieces for melted or hardened spots left by an iron.
6. Feel for static. A garment that crackles or clings when you pull it on is showing polyester’s tendency to build static.

How do you care for polyester?

Follow the permanent care label, treat oil and grease stains before washing, and iron only on a low setting with steam. The University of Georgia Cooperative Extension gives this routine:

• Water-borne stains wash out easily; oil and grease stains need spot treatment before laundering.
• To bleach, use a dry oxygen bleach.
• Wash white polyester only with other whites.
• If pressing is needed, use a low temperature and steam, because the fibre melts if too hot.

Is polyester sustainable?

Polyester is mostly made from fossil fuels, and only a small share is recycled: in 2024, 88% of polyester was fossil-based and recycled polyester made up 12% of the market, according to Textile Exchange’s Materials Market Report 2025. Production rose from about 71 million tonnes in 2023 to about 78 million tonnes in 2024, making polyester 59% of global fibre output.

Recycled polyester is still made 98% from plastic bottles, not from old clothes, according to the same report. Britannica describes PET as the most widely recycled plastic, with bottles commonly melted down and spun into fibres. As of 2024, recycled polyester therefore almost always meant bottle plastic, not clothing turned back into clothing.

Washing is a second issue. A 2017 global evaluation for the International Union for Conservation of Nature (IUCN) found that, in its central estimate, laundering synthetic textiles accounted for 34.8% of the primary microplastics it estimated were released to the oceans. That figure covers all synthetic textiles, not polyester alone.