Polymers and composites continue to drive the automotive market

Paul Boughton
Vehicle manufacturers want to replace expensive, heavy metal parts with cheaper and lighter polymers and composites. The result is a raft of new products and opportunities for chemical companies.

The latest developments from polymer manufacturing companies are demonstrating just how important the automobile sector is when it comes to driving innovation and providing new opportunities for chemical companies.

Underbody shielding manufactured by Takeo Automotive Systems and made of SymaLITE from Quadrant Plastics Composites has been specified for the BMW Z4. The lightweight shielding covers a significant part of the car's underbody, resulting in enhancement of aerodynamics, a more comfortable, silent ride and better fuel efficiency.

The shielding is developed and manufactured by Takeo Automotive Systems, Diefurt, Germany, in close cooperation with Quadrant Plastic Composites on design support, tool development, processing line lay-out and the selection of new material grades based on OEM specifications.

The BMW Z4 SymaLITE shielding is made of a layered, sandwich-like core structure, providing excellent acoustic properties as well as a higher stiffness-to-weight ratio compared with injection moulded parts or other alternative material solutions.

An acoustic fleece replaces a thin polymer film on the road-facing side and improves noise damping significantly. Moisture can penetrate the material, but is quickly released without affecting the functionality of the part, while the upper surface is closed and thus impermeable to water, petrol or oil.

According to Harri Dittmar, automotive product manager at Quadrant Plastics Composites: "SymaLITE is an intelligent composite material with specially orientated glass fibres that give it superior rigidity and shape at low weight. By varying the mix of fibre and PP resins in relation to the functional surface layers, the material's properties can be adapted to match the performance demands of the part, giving greater design and processing flexibility than competitive offerings."

The open cellular structure of SymaLITE provides excellent acoustic properties, reducing engine and gearbox noise and driving noise levels. Rolling noise is also highly absorbed which further reduces the interior noise level. In addition to superior noise absorption qualities, SymaLITE underbody shields and wheel arch liners are extremely tough and stiff and offer excellent resistance to aging, crack development, stone-chipping and material deformation.

"We have established a close and highly successful co-operation with Quadrant. This allows us to combine our know-how in underbody design and production technology with the material knowledge of Quadrant Plastic Composites to produce superior parts like the SymaLITE body shields," said Frank Heisler, owner and ceo of Takeo Automotive Systems. "We are delighted to see how successful these parts are with leading OEMs and the acoustic improvements and fuel efficiency benefits they bring to the driver."

The use of SymaLITE as a material for underbody shields began with BMW in 2003. The material is now being widely adopted by other OEMs, including Porsche, Toyota and Audi.

Meanwhile, Magneti Marelli has chosen Rhodia's Technyl to produce the air intake manifold (AIM) and the fuel rail of the Citroën C4 and the C5 2l biofuel engines in Brazil. This choice is extended to Peugeot 407, 307 and 308 series (Fig. 1).

The two partners have worked in closed collaboration on this project, as Rhodia Brazil developed the simulation analysis while Magneti Marelli Brazil dealt with parts validations.

The collaboration of European and Brazilian teams from PSA, Magneti Marelli and Rhodia has led to the homologation of Technyl A 218 V30 black, a glass fibre reinforced 6.6 polyamide, for both the AIM as well as the fuel rail used for the Brazilian market, a large user of bio-fuels with the flex-fuel system.

Rhodia has already developed a strong experience in under-the-hood applications for flex-fuel engines. Indeed, besides its position of major actor of the PA 6.6 market and its Brazilian experience, Rhodia has developed a strong expertise in the field of permeation, acquired in its CNRS shared laboratory. Rhodia can thus support its automotive customers to face the new challenges imposed by European norms.

Technyl PA 6.6 is then the material of choice, resisting to high temperature and providing good permeability resistance for under-the-hood applications of the new vehicles.

To demonstrate how its materials can meet the evolving requirements of Mexico's key industries, SABIC Innovative Plastics showcased at Plastimagen Mexico 2010 the following applications, among others: Buick Lacrosse floor console featuring STAMAX long glass fibre polypropylene resin. The material delivers 10-15 per cent cost savings and 20 per cent mass reduction, and enables parts integration; Cadillac CTS Wagon liftgate spoiler made with Cycoloy PC/ABS resin (Fig. 2).

The material provides steel-like appearance and performance, high modulus and ductility, and a low coefficient of thermal expansion (CTE) that allows tight cross-car body gaps.

In another new development, the joysteer X-by-wire system with precision gears made of Stanyl PA 46 resin from DSM Engineering Plastics is now in commercial production for the handicapped market and available from car modification companies in Switzerland, Germany and the Benelux (Fig. 3).

This rapid development from prototype to successful commercialisation was achieved by the Swiss company Bozzio within record time of just three years. In this period, Bozzio obtained the strictest level of safety approvals for the European market, making joysteer X-by-wire commercially available to provide people with a disability a user-friendly solution to drive a car with safety and confidence.

Bozzio foresees a host of potential applications for their patented X-by-wire system in special-purpose vehicles.

The gears sets made from Stanyl polyamide 46 (PA46) resin in joysteer X-by-wire system translate the driver's steering movements into vehicle control