Polyester vs Nylon vs Spandex: What's the Difference?

What's the difference between polyester, nylon and spandex? All three are man-made plastics spun into fiber, but they do different jobs. Polyester is the workhorse: it absorbs almost no water and shows up in most clothing. Nylon is a thermoplastic that started as a silk replacement and absorbs more water than polyester but far less than cotton. Spandex is the stretch ingredient, designed to replace rubber in girdles. Spandex, elastane and Lycra are not three fibers: they are the same fiber type under different names. This post sorts out the facts and the history.

Side by side

*Moisture regain, the percent of dry weight a fiber absorbs. Cotton is about 8.5 percent and polyester 0.4 percent in an IIT worked example. The ranges for other fibers come from a Wikipedia table we treat as weak-to-medium. These are fiber figures, not fabric figures. We found no sourced drying-time test, so “dries fast” is plausible, not tested. We also found no sourced tensile strength or abrasion rankings, so we won't claim nylon is “stronger.”

Polyester

PET (the plastic in bottles) was patented in 1941 by John Rex Whinfield, James Tennant Dickson and the Calico Printers' Association in Manchester, England. ICI sold it as Terylene (an inversion of “polyethylene terephthalate” per the Oxford Dictionary, as cited by Wikipedia). DuPont bought the rights in 1946 and first produced Dacron in 1950. So “polyester was invented in 1941” is partly true: that's the patent date, not a product launch. Wikipedia adds that Carothers worked on polyesters earlier and stopped, and that the British pair revived the idea. Polyester takes only disperse dyes. Under US federal rules, polyester is a polymer with at least 85 percent by weight of an ester including terephthalate units. For the PET family, see what PET, PTT and PBT mean.

Nylon, and the stocking riots

Wallace Carothers first synthesized nylon 6,6 on February 28, 1935 at DuPont's Experimental Station, per Wikipedia, and the Hagley Museum (the DuPont archive) confirms Carothers as inventor and nylon's debut at the 1939 World's Fair. Little-known: a rival nylon 6 was made by Paul Schlack at IG Farben in Germany on January 29, 1938, and nylon's first commercial product was a toothbrush in 1938, not stockings.

Stockings mattered because hemlines rose through the 1930s and silk and rayon stockings ran, says Hagley. Nylon stockings sold nationally on May 15, 1940 and sold out in two days. Wikipedia says 64 million pairs sold the first year (single source). Nylon left the consumer market in 1942 for parachutes and rope. During the shortage, women painted “liquid stockings” and drew seam lines with eyeliner, and leg-makeup bars opened in department stores (Hagley). After the war, DuPont launched sales with a 35-foot-tall leg in Los Angeles, and in Pittsburgh 40,000 people queued for 13,000 pairs. Newspapers called it the “nylon riots,” which ran from August 1945 to March 1946. Fats Waller co-wrote a song about it, “When the Nylons Bloom Again.”

What does nylon stand for?

Not New York plus London. That myth is false, since no London group worked on it, per Wikipedia. DuPont's 1940 statement (John Eckelberry) said “nyl” was arbitrary and “on” was copied from cotton and rayon. Another DuPont account says it came from “no run,” reworked to “nilon” and then “nylon” for pronunciation. The stories conflict, so which is exact is unproven. Nylon melts rather than burns away: it's a thermoplastic with a quoted melting range of 374 to 664°F depending on type.

Spandex: it started with girdles

Joseph C. Shivers of DuPont is the inventor. US Patent 3,023,192 was issued February 27, 1962. IPWatchdog reports DuPont wanted to replace rubber in girdles, driven by the World War II rubber shortage, and Shivers kept working after the team was disbanded in 1950. The irony: by launch, pantyhose were replacing girdles. “Spandex” is an anagram of “expands.” It's the word in North America, elastane in continental Europe, and Lycra is a DuPont brand (now owned by another company). The US definition is a fiber with at least 85 percent segmented polyurethane. The patent title (“Segmented Copolyetherester Elastomers”) seems to conflict with that, and we could not reconcile it, so we don't state the chemistry flatly. The first name was “Fiber K.” Shivers received the 1998 Olney Medal and was inducted posthumously into the National Inventors Hall of Fame in 2018. The “invented for gym wear” idea is false.

Where they go and what happens in the wash

Polyester was about 52 percent of world fiber production in 2019, cotton about 23 percent and nylon about 5 percent (Textile Exchange as summarized by Apparel Insider, 2020; old data). A 2016 Plymouth University study estimated fibers shed per 13 pound wash load: 137,951 for a polyester-cotton blend, 496,030 for polyester and 728,789 for acrylic. So the famous 700,000 figure is for acrylic, not polyester. The study did not test nylon or spandex. More in does polyester shed microplastics. We found no sourced care instructions here, so follow the care label. For blends, see cotton vs polyester blends.

Synthetic fiber myths, graded

• “Nylon means New York plus London.” False.
• “Spandex and Lycra are different fibers.” False. Brand versus generic name.
• “Spandex was invented for gym wear.” False. It was for girdles.
• “Polyester doesn't absorb water.” True at the fiber level (0.4 percent).
• “Nylon stockings caused riots.” True for the 1945 to 1946 shortage, though “riot” was a newspaper label.
• “Polyester was invented in 1941.” Partly. That's the patent date.

Sources & further reading

• Hagley Museum, Nylon (2024)
• Wikipedia, Nylon, Nylon riots, Spandex, PET, Polyester and Yarn conditioning
• IPWatchdog (2018), Spandex patent and Joseph Shivers
• eCFR, 16 CFR Part 303
• University of Plymouth (2016), microfiber study news release
• Apparel Insider (2020), Use of rPET plateaus