Nylon — The First Synthetic Fiber, Invented at DuPont

Wallace Carothers' 1937 DuPont patent describes nylon — the world's first fully synthetic textile fiber, created from coal, water, and air, which launched the synthetic materials industry.

What it covers

This patent describes a method for creating polyamide fibers — long-chain polymer molecules made by reacting diamines with dibasic acids (or their derivatives). The key process is melt-spinning: the polymer is melted, forced through tiny holes in a metal plate (a spinneret), and then drawn out as thin fibers that solidify as they cool. As the fibers are drawn under tension, the polymer chains align along the fiber's axis, dramatically increasing tensile strength and elasticity. The result is a strong, flexible, smooth fiber that can be woven into fabric. Unlike natural fibers (cotton, silk, wool), nylon's properties are controlled entirely by the chemical composition and manufacturing process — the same chemistry that makes fishing line strong makes hosiery sheer.

What it doesn't cover

• —Polyester fiber (Dacron) — a different polymer chemistry developed by British chemists in 1941
• —Aramid fibers like Kevlar — a related but much stronger polyamide structure developed later at DuPont
• —Nylon's use in engineering plastics (gears, bearings, structural parts) — the patent covers fiber, not molded forms
• —The specific nylon-6 chemistry — Carothers' patent covers nylon-6,6 (from hexamethylenediamine + adipic acid); nylon-6 is a different but related polymer

The clever bit

Silk was the luxury fiber of the ancient world — strong, smooth, and lustrous, but dependent on silkworms and expensive to produce. Carothers set out to understand why natural polymers (silk, rubber, cellulose) had such useful properties, by synthesizing simpler artificial versions and studying their structure. The insight was that extremely long molecular chains — polymerization — were responsible. If you could create long enough chains, you could mimic or exceed natural materials. Nylon-6,6's specific structure gives it both strength (from the aligned chain structure when drawn) and a smooth feel (from its chemical regularity). DuPont announced nylon stockings to the public in 1939; 64 million pairs sold in the first year. Carothers died by suicide in 1937, the year his patent was filed, and never saw the product go to market.

Why it matters

Nylon was the proof-of-concept that synthetic materials could replace natural ones — and do it better. It launched DuPont's slogan 'Better Living Through Chemistry' and opened the era of polymer science that gave us polyester, Spandex, Kevlar, Gore-Tex, and thousands of other materials. Carothers was one of the most brilliant chemists of the 20th century; his fundamental research into polymer structure underpins all of modern plastics and synthetic fiber science. He never received credit during his lifetime — DuPont kept his work secret to protect competitive advantage, and he struggled with depression throughout his career.

Real-world examples

• 1.DuPont launched nylon stockings on May 15, 1940 — 'N-Day' — and sold 4 million pairs in the first few hours; the term 'nylons' for hosiery dates from this launch
• 2.During World War II, all nylon production was diverted to military use: parachutes, ropes, tents, and aircraft fuel tanks
• 3.Today nylon is used in toothbrushes, fishing line, guitar strings, airbags, zip ties, and performance athletic wear — a $35 billion global market

Glossary