When Wallace H. Carothers (1896-1937) began to work as an organic chemist at DuPont Experimental Station laboratory near Wilmington, Delaware, in February 1928, he and his team were to study how and why molecules joined up to form larger ones. By 1930 Carothers had extracted a very elastic, yet extremely strong fiber from a mass of polymers. Further experiments eventually produced, by 28 February 1935, what came to be known as nylon (66), a compact, yet silk-like, elastic and quite resilient artificial fiber with better weathering properties, mildew resistance and more versatile applicability than natural fibers.
In 1938, DuPont commercialized this first man-made synthetic fiber in the form of toothbrush bristles, as yet without much public notice. What made nylon’s day was the announcement of the first-ever nylon stockings at the 1939 New York World Fair.
Thus launched nationally, nylon stockings were a hit from the start, although time proved them to be far from perfect since in hot weather they became charged with so much static electricity that undressing produced showers of bristling sparks; turning yellowish after a while was another shortcoming.
World War II interfered with internationalizing this much coveted (and still costly) female hosiery, and American servicemen abroad who could offer them as a gift to the girls of their choice were generally welcomed with open arms. After the War, nylon stockings became a hit on the West European black market, especially in England, as postwar economy focused on exports, not imports. In April 1950, so the story goes, customs officers found the transatlantic liner Franconia, docked in Liverpool, literally stuffed with nylon stockings, having in all “an estimated black market value of over £80,000” (G. Tibballs. The Guinness Book of Innovations. Enfield: Guinness Publ., 1994. p. 109).
During the Second World War, DuPont had further developed variations of nylon fibers as a replacement for silk in military applications such as parachutes and flak vest, or as an added component of vehicle tires. Today nylon 6 and 66 fibers are used, for example, in carpets, food packaging, filaments, as powder coating, to make strings for musical instruments, and, most importantly, to make car components.
More about the History of Nylon can be found here. You may enjoy reading this description in Popular Science of “How Nylon Yarn is Made” (Jan. 1946).