TPE Compound used on Peugeots
07 November 2007
For the cowl vent seals on two series of Peugeot automobiles, a leading injection moulding company based in Switzerland has specified a Tekron thermoplastic elastomer (TPE) compound supplied in Europe by Chem Polymer, a unit of Teknor Apex.
Weidmann Plastics Technology AG selected the TPE because of its unusual combination of rubber-like mechanical properties, outstanding weathering resistance, and ease-of-processing, according to the company.
Situated between the windshield and the engine compartment, and spanning the width of the vehicle, a cowl vent permits fresh air to pass from the outside world to the interior. For the Peugeot 207 and 307 series cars, Weidmann over-moulds sealing lips of Tekron TPE that are up to 1.5m long onto cowl vent substrates of glass-reinforced polypropylene (PP). The over-moulding is part of a single moulding cycle for a three-component part that includes the structural PP substrate, the Tekron sealing lip, and a moulded-in view port which enables the chassis number of the vehicle to be visible.
Tekron TPE provides the flow properties necessary to maintain precise tolerances and a smooth, attractive surface along the entire length of the cowl vent part, according to Weidmann. The company also cited the strong resistance of the Tekron TPE to outdoor weathering, as well as the heat stability and low compression set essential for maintaining seal integrity at the elevated temperatures in the location of the cowl vent just above the engine bay.
Teknor TPE compounds are based on styrenic block copolymers. They withstand temperatures of up to 120ºC and stay flexible even below -60ºC, noted Nick Sandland, Teknor Apex’s European market manager for TPEs. “One of the key benefits that Tekron TPEs provide for Weidmann’s cowl vent seal is their essentially non-reactive response to oxygen and ozone,” said Sandland. “Besides this superior weatherability, another important factor is the formulation of stabilisers and oxidation inhibitors provided by Teknor Apex for applications of this type.”
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