Because neoprene was more resistant to water, oils, heat and solvents than natural rubber, it was ideal for industrial uses such as telephone wire insulation and gasket and hose material in automobile engines. DuPont improved both the manufacturing process and the end product throughout the 1930s. The company discontinued the Duprene trade name in 1937 in favor of the generic “neoprene” to signify that the material is an ingredient, not a finished consumer product.
Elimination of the disagreeable odor that had plagued earlier varieties of neoprene made it popular in consumer goods like gloves and shoe soles. World War II removed neoprene from the commercial market, however, and although production at the Deepwater plant was stepped up, the military claimed it all. DuPont purchased a government-owned neoprene plant in Louisville, Ky., to keep up with increasing demand after the war. Basically unchanged since 1950, neoprene continues to be essential in the manufacture of adhesives, sealants, power transmission belts, hoses and tubes. Since 1996 neoprene has been produced under DuPont Dow Elastomers LLC, a joint venture with Dow Chemical.
DuPont's manufacturing plant on the Ohio River just outside Louisville, Ky., has been producing neoprene, or "synthetic rubber," since September 1942. When the United States entered World War II in December, the federal government purchased the plant, which DuPont continued to manage. Neoprene was a vital war material, especially when the war with Japan cut off supplies of natural rubber. At the end of 1948 DuPont bought the plant back from the government, and on January 1, 1949, the Louisville facility began operations under the company's sole ownership. The area also proved attractive to other chemical companies and soon became known as "Rubbertown." Through the 1960s and 1970s, DuPont modernized and expanded the Louisville Works. After a series of explosions and fires in August 1965 killed 11 workers there, DuPont developed new technologies for neoprene production that greatly reduced the possibility of explosions.
In 1955 the Louisville plant started manufacturing Freon-22 refrigerant and aerosol propellant. Thirty-three years later, however, plant managers began planning for a phase-out of this product when DuPont decided to curtail all production of ozone-depleting chlorofluorocarbon (CFC) products for U.S. markets. By 1992 Louisville was producing ozone-safe, non-CFC substitutes like Suva® refrigerants and Dymel® propellants. In 1998, just after DuPont acquired Protein Technologies International, Louisville started producing protein isolates, or concentrated soy protein, for industrial applications like paper and paperboard coatings. Through nearly 60 years of change, however, the plant continued to make its original and versatile product — neoprene.