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MATERIALS: Ultra-Soft TPVs Replace EPDM Foam Seals

From: Plastics Technology
Issue: December 2011

Two new PP-based Sarlink thermoplastic vulcanizates (TPVs) are said to provide the first practical alternative to EPDM foam or sponge in automotive seals, construction weatherstripping, gaskets, and other profiles requiring high resilience. Teknor Apex Co., Pawtucket, R.I., introduced these materials at the recent Fakuma show in Germany. Sarlink 5725B and 5735B have Shore A hardnesses of 25 and 35, respectively. They are said to be the softest TPVs available for extrusion and exhibit the lowest compression set, making them competitive with EPDM foam, but with the advantages of a thermoplastic over a thermoset. In addition, TPVs can be coextruded with stiff polyolefins for rigidity or attachment requirements, while EPDM requires the costly step of encapsulating metal. Like other compounds in the Sarlink 5700 Series, they boast high UV resistance and improved anti-fogging properties.