DuPont Performance Elastomers Celebrates 50th Anniversary of Viton® Fluoroelastomers
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Date: 10/9/2007
This year, 2007, is the 50th anniversary of the commercialization of Viton® and the birth of the fluoroelastomers industry. Since the first commercial application of Viton® in the aerospace industry in 1957, fluoroelastomers (FKM) have made a major contribution to fluid sealing and containment in industries as diverse as aerospace and automotive, chemical, petrochemical, food and pharmaceutical processing, and construction. Fluoroelastomers now represent a global industry with total annual sales volume expected to reach an estimated 20 thousand tons in 2007.
How the Story Began
Dr. Dean R. Rexford of the DuPont Organics Chemicals Department, Wilmington, Delaware, USA, credited with leading the development of Viton®
The story began in April 1954, when Dr. Dean R. Rexford of the DuPont Organics Chemicals Department in Wilmington, Delaware, USA, was experimenting with a new elastomer with high temperature and chemical resistance. Unfortunately, there was one major barrier. Commercial scale polymerization of the materials used to make this product was considered a significant potential safety risk. It was up to Dr. Rexford, chemist and inventor, to tackle this issue. Following a controlled reaction involving hexafluoropropene, vinylidene fluoride and polymerization initiators, an elastic 60/40 HFP/VF2 copolymer was obtained. Its elastomeric properties were sufficiently exciting for the company to file U.S. Patent Application No. 504,351 on April 27, 1954, to protect the discovery. Corresponding U.S. Patent No. 3,051,677 was issued on August 28, 1962.
Records show that 100 grams of the new product, known at that time as RCD-2077, were sent for sampling by the Wright Air Development Center at Wright-Patterson Air Force Base, Ohio, USA, on April 10, 1956. By December 1956 the name Viton® had been chosen from five other proposals, and the first use of the now familiar trademark was claimed. Commercial scale production of Viton® A fluoroelastomer began in August 1957 with an original Mooney viscosity specification of 30 to 60!
Step Change Improvement
Compared to other elastomers available at that time, Viton® A provided step change improvement in high temperature stability and compression set resistance, and in resistance to many aggressive fluids. Its ability to withstand aviation fuels and oils made it a natural fit for the aerospace industry.
Following its success in aerospace applications, Viton® quickly found a key place in a myriad of applications, and in particular the automotive industry where its permeation resistance to aggressive fuels enables motor manufacturers to meet stringent global evaporative emissions legislation. Product development throughout its 50 years has resulted in improvements in processing, low temperature capabilities and improved fluids resistance. One of the most important was the development of Advanced Polymer Architecture designed for the manufacture of specialty fluoroelastomers. Fluoroelastomer O-rings, hoses, gaskets and diaphragms make a major contribution to fluid sealing and containment in industries as diverse as aerospace and automotive, chemical, petrochemical, food and pharmaceutical processing and construction. Seen here are oil seals (left) and automotive shaft seals (right) made of Viton® fluoroelastomers, used extensively due to their heat and oil resistance.
Advanced Polymer Architecture
Specialty fluoroelastomers are designed for the upper end of FKM performance in the most demanding operating environments, but these specialty products had always been more difficult to process than the standard products. Fluoroelastomer producers strived to combine the best of both types, the processability of the standard types, with the outstanding performance of the specialty products.
A technical breakthrough in 2001, resulting from a $60 million investment program by the former DuPont Dow Elastomers, now DuPont Performance Elastomers (DPE), made this possible. Called Advanced Polymer Architecture (APA), this was another significant step forward in fluoroelastomer capability. APA is a result of a proprietary advance in polymer structure and the development of new cure site technology. It offers flow, cure and mold release processibility properties approaching those of a standard fluoroelastomer, and final part performance equivalent to that of the best specialty products. These objectives were realized by the commercialization of the first APA polymers in 2002 - Viton® GF-S, GBL-S, GLT-S, GBLT-S and GFLT-S.
Since then, DPE has added steadily to the growing portfolio of APA 'S' types including new low temperature, peroxide and base resistant products. For highlights of 50 years of innovation and Viton®, please visit www.viton50.com
About DuPont Performance Elastomers
DuPont Performance Elastomers, a global supplier of specialty elastomers with European headquarters in Geneva, Switzerland, is a wholly owned subsidiary of DuPont. The company is an industry leader in chloroelastomers and fluorinated elastomers, serving the automotive, chemical, petrochemical, semiconductor, food and pharmaceutical processing, construction, general rubber and wire and cable industries.
