25/02/2015

www.gupta-verlag.de/thermoplastic-elastomers

Elastollan TPU used on the exterior of the new Citroën C4 Cactus

[image_0]The automotive manufacturer PSA Peugeot Citroën uses the new TPU grade Elastollan AC 55D10 HPM (High Performance Material) for cladding the Citroën C4 Cactus with so-called Airbumps. These are large air-filled cushion bumpers in contrasting colours. They are fitted on the sides as well as on the front and rear of the vehicle, protect the car exterior from impact and scratches and give the vehicle its distinctive look. This world first is the result of development work between the French automotive manufacturer, the supplier Rehau, Switzerland, and BASF. Rehau manufactures the side Airbumps, while the company Faurecia, France, produces the bumpers at the front and back. According to BASF, the advantage of Elastollan HPM lies in its freedom of design and long-term durability together with attractive haptics and a high-class appearance. The new material combines the properties of conventional TPU, such as good tensile strength and abrasion resistance, elasticity, good impact resistance at low temperatures and high media resistance, with new features: It has outstanding surface properties even at low wall thicknesses, it is scratch-resistant, UV- and weather-resistant, is easy to clean and has a high service temperature of 120 to 150 °C, says BASF. The injection-moulded Elastollan component is mounted to a polycarbonate and acrylonitrile-butadiene-styrene (ABS) support shell, thus forming flexible cavities that can be dented and bounce back again. The entire structure is fixed to the metal chassis. Because of the good mounting properties of the HPM grade a tight assemblage is possible which conventional trim materials such as polypropylene do not achieve. Elastollan HPM can be pigmented, so the Airbumps do not have to be painted. Thus, they do not require any special maintenance and in case of an accident help reduce the repair costs for the vehicle. The bumpers are available in four contrasting colours (black, brown, light and dark gray) and contribute to the harmonious individual colour design with the automotive coatings, primers and clearcoats from BASF's Coatings Division. BASF says it has also further developed the processing properties of the new Elastollan grade. The material can be injection-moulded within a wide process window with a cycle time that is 50 % shorter compared with conventional TPU. It has good flow properties, which means that low wall thicknesses of 1.5 - 1.8 mm can be produced without affecting the surface quality. "Because of the high demands on surface and colour, hardness and flexibility the close cooperation with BASF in material formulation and application development was a decisive factor for us”, explained Bernard Delles, Project Head at the automotive supplier Rehau, which manufactures the side Airbumps. Faurecia uses the new Elastollan HPM for manufacturing the bumpers at the front and back of the C4 Cactus. "The innovation lay not only in the material but also in the mounting. BASF has developed a plastic that required a new assembly technology. We worked closely to meet the requirements for the industrial mass production of these unusual parts”, said Sébastien Bret, Development Manager at Faurecia. Up to now, Elastollan has been used in the automotive industry as cable sheathing, in the engine compartment and in the vehicle interior, e. g. for door handles, gear knobs and cupholder linings. The TPU can be injection-moulded, extruded or blow-moulded.

www.gupta-verlag.de/thermoplastic-elastomers