Innovation does not happen in isolation; it is a battleground where ideas clash, rivalries ignite, and ownership defines the future. Behind the technologies we rely on every day lie stories of groundbreaking inventions entangled in fierce legal disputes. Patents have driven progress, and sometimes stalled it. Welcome to Patent Feuds: The Untold Battles That Shaped Innovation. In this series, we uncover the rivalries that transformed industries, the inventions that triggered legal wars, and the lasting impact of Intellectual Property on the world. Get ready to explore the drama, the ambition, and the ideas that shaped modern history.
The Birth of a Name and a Revolution
Ever wondered how nylon gets its name? The term “NYLON” was created by DuPont as a catchy, modern name that was easy to remember and market. Basically, the “NY” was taken from “New York,” where DuPont marketed the fabric, while the “Lon” was believed to imply “London” (a European centre of fashion) or simply an invented suffix to convey modernity and innovation. This new brand name helped spin the fabric into a global phenomenon, setting the stage for both a commercial revolution and an international patent feud that would determine who truly owned the future of synthetic fibres.
The Invention: How Nylon Emerged from the Lab
The origin of nylon begins not with weaving looms but in the halls of DuPont’s research laboratories. During the 1920s, DuPont was already a name synonymous with innovative chemistry, branching out from its earlier legacy in gunpowder manufacturing. Seeking to redefine everyday materials, DuPont established its Experimental Station in 1927 with a bold new goal: to invent a fully synthetic fiber that could rival and surpass natural textiles.
The Pioneers Behind the Breakthrough
The driving force behind this innovation was Dr. Wallace Hume Carothers, an extraordinarily talented organic chemist with a flair for polymers. Under Carothers’ leadership, the research team spun new possibilities for synthetic materials. Their breakthrough came in 1935 when they successfully synthesized a polymer from hexamethylenediamine and adipic acid, a process that created long-chain molecules with remarkable strength and elasticity.
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This new fiber, later known as nylon 6,6 was not only stronger than silk but also more uniform and versatile than any available natural fiber. On February 16, 1937, DuPont secured U.S. Patent No. 2,071,250, titled “Linear condensation polymers,” covering the method for producing what we now celebrate as nylon 6,6.
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Though Carothers tragically died in 1937, his legacy spun onward. At the 1939 New York World’s Fair, DuPont introduced nylon to the public with the promise of “Better Things for Better Living… Through Chemistry,” indicating a new era for both fashion and industry.
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The Feud Ignites: The DuPont vs. IG Farben Showdown
As DuPont prepared to spin nylon into a worldwide commercial product, a rival was quietly forging its path in Germany. IG Farben, a powerful chemical conglomerate, was also delving into the potential of synthetic fibers. Led by chemist Paul Schlack, IG Farben developed an alternative method to produce nylon, which was chemically different, yet produced fibers that looked and felt strikingly similar to DuPont’s creation.
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DuPont’s nylon 6,6 product was produced using a step-growth condensation polymerization method combining hexamethylenediamine and adipic acid. In comparison, IG Farben’s version, nylon 6, was created by ring-opening polymerization of caprolactam. Though visually similar when spun into fibers, these two forms had different polymer structures, resulting in differences in properties like melting point, crystallinity, and moisture absorption.
Patent Feuds and International Legal Wrangling
DuPont was aggressive in defending its patent rights, particularly under U.S. Patent No. 2,071,250. Meanwhile, IG Farben filed its own patent application for its own invention, which resulted in U.S. Patent 2,241,321. DuPont attempted to block imports of nylon 6-based products, arguing patent infringement. IG Farben maintained that the differences in chemical composition and manufacturing method rendered their nylon 6 non-infringing and independently patentable.
The spinning rivalry escalated into a classic battle of patent scope, novelty, and non-obviousness terms familiar to any IP practitioner. The issue centered on whether a different polymerization route that produced a functionally similar material could be protected under a new patent or whether it fell under DuPont’s broader claims.
The Technical Battleground: Nylon 6 vs. Nylon 6,6
Nylon 6 and Nylon 6,6 may look similar, but they are technically different in several important ways. Nylon 6,6 is made using two different monomers and combining them in a process called condensation polymerization. This gives the fiber a high melting point (around 265°C) and great tensile strength, making it suitable for demanding applications where heat resistance and durability are crucial.
On the other hand, IG Farben’s Nylon 6 is made from a single monomer, caprolactam, using ring-opening polymerization. Nylon 6 melts at a lower temperature (around 220°C) and has lower mechanical strength but is more flexible. Importantly, Nylon 6 is easier and cheaper to produce in large quantities, which makes it commercially accessible. While Nylon 6,6 performs better in high-performance spinning applications, Nylon 6 is useful for mass production due to its cost-effectiveness and ease of processing.
DuPont asserted that its process and product were novel and non-obvious, claiming that IG Farben’s nylon 6 was a workaround to their protected invention. IG Farben countered by stating that their process used entirely different chemistry, therefore qualifying as an independent invention.
War, Secrecy, and a Pause on the Feud
Then came World War II, and everything changed.
The onset of World War II caused a dramatic shift. Nylon became critical to military supplies: parachutes, ropes, tires, and more. DuPont halted civilian production and spun all its efforts into wartime materials. Meanwhile, IG Farben’s Perlon (nylon 6) served the Axis military needs.
During the war, legal actions were suspended. After Germany’s defeat, the Allies bombed and dismantled IG Farben, seizing many of its patents. This indirectly benefited DuPont, as legal pressure was reduced, and they now had access to the German market.
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The Legal Aftermath: Parallel Paths for Synthetic Fibers
After the war, DuPont sought to reassert its global dominance over synthetic fiber production. However, courts in Europe and Asia ruled that nylon 6 had sufficient chemical differences to qualify as a distinct invention. Thus, DuPont’s patent rights largely remained limited to the U.S., while European and Asian companies (like BASF, Toray, and Asahi Kasei) spun nylon 6 into massive commercial successes. Nylon fiber produced by the polymerization of monomers is extruded to form filaments these filaments are spun to form yarn which is then woven or knitted to form fabric.
After World War II, DuPont did not share its nylon technology with IG Farben. Instead, DuPont later worked with companies like BASF, Toray, and Asahi Kasei, letting them use the nylon 6 process. This helped both nylon 6 and DuPont’s nylon 6,6 grow worldwide without legal fights. DuPont had exclusive rights to nylon 6,6 in the U.S. until its patent ended in 1954, earning good money from licenses. After that, both nylon types coexisted peacefully, each becoming popular in different markets.
Conclusion: Same Family, Different Threads
Though chemically related as polyamides, nylon 6 and nylon 6,6 are structurally distinct due to their different monomer sources and polymerization techniques. This was central to the patent battle, which remains a textbook case in patent law on the limits of claim breadth, independent invention, and industrial application.
The “Spin Wars” over nylon did not end in one winner taking all, but spun the entire industry forward, making way for a broad field of synthetic fibers like polyester, acrylics, and spandex.
In patent language, the feud was defined by novelty, non-obviousness, independent invention, claim scope, and market exclusion strategies. But in industrial terms, it was about who could spin the future first and best.
The nylon feud ended, but the game to invent never does. Your move.
R K Dewan & Co. is a Patent law firm in India with over 79 years of experience in the field of Intellectual Property. With offices in Mumbai, New Delhi, Pune, Chennai, Kolkata, Bangalore, and Indore, RKD serves more than 5000 clients, both in India and internationally, assisting them in securing, enforcing, and commercializing their IP rights across India and in over 125 countries. The firm has a team of 175+ professionals, focused on providing efficient and prompt services. ISO 9001:2015 certified, RKD handles all aspects of IP, including, trademarks, copyrights, designs, geographical indications, plant varieties, and traditional knowledge. RKD offers services in filing, prosecution, hearings, appeals, oppositions, cancellations, commercialization, brand valuation, litigation at all judicial levels, portfolio management, and anti-counterfeiting actions.