CLEVELAND—Two new grades of ethylene acrylic elastomers—Vamac VMX5000 and VMX2122—formed the centerpiece of DuPont Performance Elastomers' offerings at the recent International Elastomer Conference in Cleveland.
Vamac VMX5000 pre-compounds are designed for use in seals and gaskets, air management systems and high-temperature coolant hose covers, a news release from DuPont Performance Elastomers said.
VMX5000 is particularly useful in the manufacture of hose and gaskets for turbo-powered vehicles, according to John Huber, DuPont Automotive market development manager, and Eileen Wood, DuPont Vamac regional director, Americas.
He said the major difference between VMX5000 and other Vamac grades is a polymer compounded in the mix that increases the heat resistance of VMX5000 some 15 to 20 degrees Celsius above that of similar products on the market.
“VMX5000 closes the gap between performance and heat resistance,” he said. The higher temperature applications of VMX5000 allow it to go into markets where more expensive elastomers previously dominated, he said.
Another major benefit to using VMX5000 is that its compression set is much better than other Vamac products, according to Wood.
“This is an upgrade within the outside-the-box upgrade that VMX5000 represents,” she said.
VMX5000 also can be pigmented without losing compression set or physical properties, Huber and Wood.
“This was previously a big problem for customers,” Wood said. “They didn't want to pigment auto parts because they would lose physical properties.”
A number of original equipment manufacturers are in varying stages of specifying VMX5000 for their vehicles, Wood and Huber said.
Nevertheless, products made with VMX5000 and other Vamac elastomers still have to be post-cured, Huber said. That is where Vamac VMX2122 comes in.
“The challenge is that some folks may not want to post-cure,” he said. But VMX2122 is a dipolymer that doesn't require post-cure.
“The material is cured in the mold,” Huber said. “People say they have bigger parts they want to configure that they don't want to post-cure.
“This is a next-generation dipolymer that represents a significant improvement over previous dipolymers. It was a challenge to put together.”
According to company publicity, VMX2122 can have an injection molding cycle time of less than two minutes and still have good compression set values without post-curing. VMX2122 compounds do not have die build-up problems, the firm said.
VMX2122 is appropriate for auto, wire and cable use, along with other applications, Huber and Wood said.