Synthetic Rubber Industry Sprouts from Stolen Seeds

Before World War II, synthetic rubber was an expensive, impractical curiosity. Who needed it? Even with the worldwide automobile boom in the wake of World War I, the plantations of the enormous East Asian rubber industry were so efficient that the 1930s enjoyed a global glut of rubber exports.

But by June 1940, rubber had become so crucial that President Roosevelt declared it a strategic material. Supplying the world with strategic material is difficult even in the best of times — and for East Asia, the 1940s were the worst of times. As war spread around the world, rubber supply ships had to run a gauntlet of Uboats in the Atlantic. Then in 1941, Japan invaded and conquered Indochina, and rubber exports stopped.

Ironically, the British, by cultivating their own Asian supplies of rubber, cut themselves and their allies off from natural rubber just as they needed it most, thus propelling the development of synthetic rubber from curiosity to a major industry.

Smuggled Start Up
The story begins in the 1800s, when Brazil supplied most of the global demand for natural rubber. To protect its market, Brazil banned the export of seeds. Despite the ban, enterprising agents of the British Empire smuggled rubber tree seeds to England in 1876.

Carefully cultivated seedlings were sent to Ceylon and later to Java, Sumatra and the Malay Peninsula. Colonial managers ran the plantations carefully and profitably. Soon, Asian plantations gained control of the world market, and the Brazilian plantations slowly died off. So when Japan invaded, Britain and its allies faced World War II with an army that rolled on rubber tires and a dwindling stockpile of natural rubber.

Enter Government Rubber-Styrene
In 1941 the U.S. entered the war. With Asian rubber plantations in Japanese hands and U-boats patrolling the Atlantic, the U.S. was also cut off from both major and minor suppliers of natural rubber. Several major U.S. rubber manufacturers, including Goodyear and Goodrich, stepped up research on synthetic rubber compounds they had begun developing in the 1930s. The most promising of these compounds, and still the leading synthetic rubber today, is SBR, or styrene-butadiene rubber.

Initially, SBR proved difficult to process in existing rubber manufacturing equipment. But SBR has many appealing characteristics. Chief among these is that it blends easily with natural rubber. So SBR could be processed with natural rubber in existing equipment.

In 1929, two chemists working for I.G. Farben of Leverkeusen, Germany, were the first to patent SBR, using the trade name Buna S. But the Great Depression and low natural rubber prices shelved their work. Between 1932 and 1934, both Goodyear and Goodrich began independent research into synthetic rubber after they failed to reach license agreements with I.G. Farben.

For the American manufacturers the first priority in the 1930S was to develop a synthetic rubber compound that required no agreement with their German competitor. At Goodrich the codename for the first promising compound was “nirub,” short for “Non Infringing Rubber.” But neither “nirub” nor any other compound could match Buna S.

With war on the horizon and Germany a likely enemy, the U.S. Government formed the Rubber Reserve Company in June of 1940. The worldwide war effort could easily go flat without sufficient rubber supplies. In December of 1941, the U.S. declared war on Germany, Japan and their allies. In 1942, the search for alternatives to Buna S stopped. Rubber reserves were dangerously low. The German compound was christened GR-S (Government Rubber-Styrene) and plans for producing hundreds of thousands of tons of syntheitic rubber were set in motion.

Whiskey Goes to War
Daunting obstacles lay in the path of the effort to develop a synthetic rubber industry in months rather than in years. First among these was a short supply of butadiene. Many sources of butadiene supply were proposed and rejected in 1941.

In 1942, a record grain harvest provided the answer. The whiskey industry could easily shift capacity to produce enough ethanol to make butadiene. Cadillac made tanks, DuPont made parachutes in preference to hosiery, and whiskey makers quenched the synthetic rubber industry’s thirst for raw materials.

After World War II, the Cold War kept government-sponsored development of synthetic rubber alive well into the 1950s. Natural rubber still accounts for a significant segment of the world market, but synthetic rubber took over the top spot in the war years and has remained there ever since.

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This article was originally published under the title "We're History" in the April 2003 edition of Chemical Engineering Progress magazine. This article was prepared by Neil Gussman, communications manager for the Chemical Heritage Foundation.This article is based on a chapter from the book “The American Synthetic Rubber Industry” by Peter J. T. Morris, available from CHF Press.