PLYMOUTH, Mich. (Jan. 8, 2010)—Sealing and vibration control specialist Freudenberg-NOK G.P. has developed a fluorinated thermoplastic material that provides the processing benefits of a plastic but has the flexibility and resistance of an elastomer.
The company's FluoroXprene offering can be formulated as either a thermoplastic vulcanizate or thermoplastic elastomer. The material acts similar to a high-end Santoprene—the TPV/TPE designed by Advanced Elastomer Systems L.P. and now owned by ExxonMobil—said Ed Park, Freudenberg-NOK senior staff chemist and FluoroXprene developer.
However, being fully fluorinated, the material also provides high chemical and temperature resistance, important traits for automotive industry applications, Park said. FluoroXprene's initial use was in an inner liner of a coextruded hose line for gasoline, diesel and other fuel applications.
Ted Duclos, Freudenberg-NOK vice president, operations and technology, said the material brings a combination of benefits to the table: in addition to chemical and temperature resistance and cost-effective processing ease, FluoroXprene provides permeation resistance and outstanding rubber-like qualities such as sealability.
The idea for the material came from a conversation Duclos and Joe Walker, corporate director of material development at the Plymouth-based company, had about nine years ago regarding the need for an FKM TPE in the automotive market. When they researched what was out there, they found patents in the area but none that were processable or usable.
“We wanted the chemical resistance of an FKM and the processability of a TPE,” Duclos said. “Ed (Park) made the concept practical, with the idea that we would develop different grades to fit the needs of potential applications in the future.”
FluoroXprene can be used in any sealing application, Park said, providing improvements in elastomer or plastic solutions.
In the inner liner application, for example, Freudenberg-NOK believes the FluoroXprene-based product is a better liner than one processed with FKM, and also improves greatly on the sealability of a plastic product, he said.
The plastic component of the material also adds to its recyclability, thus reducing waste and processing costs, Park said. Therefore, despite it being a “high-end” material, from a total-cost standpoint it isn't necessarily limited to high-cost applications, he said.
While material development is “a little bit of a step out” for the traditional rubber sealing manufacturer—which serves the automotive, medical, oil and gas, aerospace and several other markets—having material capabilities is an important part of the company's goal to improve its products, Duclos said.
One of the firm's parent companies, NOK Corp. in Japan—Freudenberg & Co. in Germany is the other—is a polymer developer that specializes in its own FKM materials, so having the capability to design and develop elastomers is “part of our heritage,” he said.
Park agreed, saying that Freudenberg-NOK does many of its own unique formulations and is always striving for a better material. “It's an extension of the culture here,” he said.
One drawback to FluoroXprene is its compression set, which is usually better for rubber than plastic, Park said, but the company is working on that. Duclos said with a new product, sometimes it's necessary to examine what can be done with it now, versus what you need to do with it in the future.
Improving the compression set at higher temperatures, for example, is a goal Freudenberg-NOK has to not only make the product better but find new applications as well, he said.
“At first there was a struggle to find uses for Teflon, and we think we're on a similar path,” he said. “We know FluoroXprene fits into certain areas, but we haven't found them all yet. We believe it provides benefits you can't get with anything else. We'll expand on that.”
While the material was developed in the U.S., the company is taking a global approach in looking for future opportunities, Park and Duclos said.