What is the difference between polyester, nylon and acrylic?

Nearly all synthetic clothing is one of these three, plus elastane for stretch. Knowing which is which changes buying decisions more than washing ones, because the differences show up in how a garment wears rather than how it cleans.

Step by step

1. Recognise polyester on a label.Polyester, PET, and brand names such as Coolmax and Thermolite. It is the most common clothing fibre in the world. Strong, dimensionally stable, holds pleats and prints, dries fast, resists sunlight and mildew.
2. Recognise nylon.Labelled polyamide in Europe, and sometimes PA or by brand names. Higher abrasion resistance and higher stretch recovery than polyester, and slightly more absorbent, so it feels less clammy. It yellows in sunlight over time and is weakened by prolonged UV.
3. Recognise acrylic.Acrylic, modacrylic, and older brand names such as Courtelle. Bulky, soft and warm-feeling, designed as a wool substitute. It is cheap, it takes bright dye well, and it is the fibre in most inexpensive jumpers, blankets and fleece-lined items.
4. Compare abrasion resistance.Nylon best, polyester close behind, acrylic clearly worst. This is why rucksacks, jacket linings and hosiery are nylon and why an acrylic jumper looks tired quickly.
5. Compare pilling.Acrylic worst by a wide margin — short, strong fibre in soft yarn is the perfect pilling recipe. Polyester bad in knits, fine in tight wovens. Nylon better than both in most constructions.
6. Compare heat tolerance.All three melt. Acrylic is the most heat-sensitive and will glaze or melt under an iron with very little provocation; nylon is next; polyester takes the most. Every one of them wants a cool iron and no tumble dryer heat if you want the garment to last.
7. Compare warmth and moisture.Acrylic feels warm dry and is poor wet, as it holds moisture in the structure without wicking. Polyester wicks well and dries fastest. Nylon absorbs a little more and dries a little slower than polyester.
8. Compare odour.All three hold body oil on a hydrophobic surface and develop the persistent synthetic smell. Polyester and polypropylene are the worst; nylon slightly better; acrylic in the middle but less relevant because it is rarely worn next to skin during exercise.

Tips

• Acrylic in a blend with wool is common and does two things: it lowers the price and it makes the garment pill much more than pure wool would.
• A fleece is almost always polyester; a fluffy soft-toy or blanket texture is more likely acrylic. The difference matters for the iron.
• None of the three should meet direct heat. A synthetic touching a hot radiator or a heated airer element can melt and glaze permanently.
• Nylon linings are what stop a coat abrading the jumper underneath. A worn, roughened lining is a common hidden cause of pilling.

Common mistakes

• Ironing acrylic at the wool setting because it looks like wool — Acrylic melts and glazes at temperatures wool takes without complaint. The shine is permanent.
• Buying an acrylic jumper expecting wool performance — It will feel warm in the shop and pill within a month, and it will be cold when damp. It has its place as an inexpensive item, not as a jumper to keep.
• Treating polyamide as something exotic — It is simply nylon under its European label, and it wants the same care.

Alternatives

• Polypropylene: Lightest of all clothing fibres and completely non-absorbent, so it dries almost instantly. Very poor heat tolerance and notorious for odour. Now mostly displaced by polyester in base layers.
• Recycled polyester (rPET): Chemically the same as virgin polyester and behaves identically in wear and wash. The difference is in the feedstock, not the fibre.
• Wool: Where acrylic is trying to imitate wool, wool does the job better in every respect except price and machine washability — warmth when damp, odour resistance, pilling behaviour and longevity.

Questions people ask