Houston, Texas – ExxonMobil has introduced a thermoplastic vulcanisate (TPV) structure, designed to offer a sustainable alternative to EPDM-based glass-run-channel (GRC) weatherseals.
The automotive profile features Santoprene R², a TPV incorporating post-consumer recyclate (PCR), and Santoprene HR TPV, said to match the elastic-recovery of – more difficult to recycle – EPDM.
In the “integrated” structure, Santoprene R² is used for the foot element of the profile, while Santoprene HR is used for the lips and skins of GRC profiles, explained the company statement, issued 19 Jan.
For other mechanical properties, both grades deliver a similar performance to EPDM, according to ExxonMobil, noting that TPV scrap generated during weatherseal manufacture can be melted down and remoulded.
“Initiatives like the EU Green Deal and CHINA VI are driving the automotive value chain to constantly consider how new sustainability objectives can be achieved,” said Dan Moore, vice president specialty elastomers and butyl, ExxonMobil.
A particular target area is frame-under-glass GRCs, which are widely used in Europe and increasingly also in Asia Pacific, These are typically made with a metal frame and EPDM rubber.
In this application, Santoprene HR TPV is “a viable replacement for EPDM rubber currently used for semi-dynamic weatherseal applications,” said ExxonMobil, adding that use in dynamic weatherseals is also being examined.
Until now, EPDM has been the material of choice for highly demanding semi-dynamic and dynamic seals, according to Leslie Chan, global SE&B market development manager at ExxonMobil.
“The improved performance properties of Santoprene HR TPV, including resilience and elastic recovery, unleash the potential use of TPV as an EPDM alternative for more demanding dynamic applications,” said Chan.
“In addition to the recycling potential, these system solutions support a reduction in weight for all types of vehicles by replacing metal reinforcement with PP and design flexibility,” added Jessica Vasquez, global SE&B product technology manager.