Leverkusen, March 2008 – With its sporty-looking contours, the "i-mode" is certainly an impressive sight. One thing that immediately catches the eye is its new door design, which does away with the center pillar, while the cockpit of Hyundai's new HED-5 "i-mode" concept car certainly promises plenty of driving pleasure. In fact, the vehicle combines the advantages of a van with those of a sedan. Many of its outstanding features have come about as a result of close development partnership between Hyundai and Bayer MaterialScience AG. "For us, it was a special challenge to work on a close-to-production concept car with one of the biggest and fastest growing international car manufacturers. This vehicle provides an impressive demonstration of our latest products and our know-how in innovative plastics processing," explains Dr. Klaus Zander, key account manager for Hyundai at Bayer MaterialScience. "We at Hyundai were looking for a partner that understands the way we think in auto design, and Bayer MaterialScience was certainly the right choice for us," observes Helmut Weixner, head of Engineering
Design at Hyundai Motor Europe.
Polycarbonate glazing – less weight and more design freedom One striking feature of the "i-mode" is its transparency. It has a total of eleven glazing components made of Makrolon®. In addition to the windscreen and backlite, the four moving and two fixed side windows, the two hinged windows and the large roof module are all made of this polycarbonate from Bayer MaterialScience. The decisive argument for using this high-tech thermoplastic was its enormous design scope. For example, the backlite extends up into the roof. "It bends round almost at right angles, which would be impossible with glass," says Ulrich Grosser, a design expert at Bayer MaterialScience.
The roof module consists of two long panels separated by a narrow center strip. Both Partnership with Hyundai on the "i-mode" concept car Premiere at the 78th International Motor Show in Geneva panels have a sharp edge that runs smoothly into the backlite. This styling element, which underscores the dynamism of the vehicle, would also have been impossible to construct with glass. Because of the large number of glazing elements and their considerable size, the material also had to be much lighter than glass. "With our polycarbonate, we can produce transparent panels that are up to 50 percent lighter than their glass counterparts," adds Grosser.
To ensure effective heat protection in the interior of the "i-mode" on sunny days, the design team has used a new generation of IR-absorbing transparent colors coordinated to Makrolon®. This glazing is able to absorb the heat of the sun's rays better than certain types of glass, but with comparable light transmission. In addition, it provides effective protection against UV radiation – unlike similar elements made of glass. Bayer MaterialScience, the market leader in the field of polycarbonate automotive glazing, has once again underlined its pioneering role as a development partner for polymeric raw materials. The "i-mode" has also provided the company with an excellent pportunity to display its wide-ranging know-how along the entire polycarbonate glazing development and production chain.
Self-healing 2-component polyurethane top coat – scratches that disappear The bodywork of the "i-mode" shimmers in a stylish silver metallic color called "Topaz Silver". In fact, the coating system used for Hyundai's concept car marks the premiere of a two-component polyurethane topcoat based on new raw materials from Bayer MaterialScience. The special thing about the vehicle's finish is its extreme scratch resistance and its self-healing properties. Small scratches simply "melt away" under the influence of the sun's heat so that the finish retains its new look for longer. Scratch resistance and self-healing characteristics may sound like contradictions, but they are not
necessarily so. A combination of properties such as this can be achieved by altering the coating's molecular network. The scratch resistance of a polyurethane finish generally can be increased by raising the density of the molecular network, but to ensure that the coating does not become brittle in the process, the areas between the linkage points of the network must be made elastic. "We do this with the aid of our new, highly functional
hardener, Desmodur® XP 2679. In combination with suitable Desmophen® polyols – the second basic raw material in this polyurethane coating – it forms a tight network with  elastic network chains," says Dr. Markus Mechtel, who specializes in bodywork finishes at Bayer MaterialScience. The resultant polyurethane clear coat is not only scratch-resistant and self-healing, it is also highly chemical-resistant. On top of all that, it is also environmentally friendly because it is formulated with a high content of polymer and only a small amount of organic solvents. Polyurethane soft-feel coating – optimized stability and long service life The soft-feel coatings applied to many of the plastic controls and surfaces in the cockpit of the "i-mode" are based on a new generation of high-grade coating materials in the Bayhydrol® and Bayhydur® series. They give the "cold" plastic surfaces a soft, warm feel
that is particularly pleasant to the touch. "Our new polyurethane raw materials are applied by spraying, resulting in soft-feel finishes that have a much longer service life and better aging resistance than the former systems. Even light-colored surfaces barely yellow at all
under the effect of heat," explains Dr. Christoph Irle, an expert in soft-feel coatings at Bayer MaterialScience. The surfaces are matt, which means that the driver is not irritated by troublesome reflections. Another bonus is that these coatings are waterborne and therefore particularly environmentally friendly. The polyurethane raw materials do not contain any plasticizer, so that the coatings exhibit minimum fogging and very low emissions.
LED headlamps – polycarbonate superior to PMMA and glass Headlamps that incorporate light-emitting diodes (LEDs) as the light source are becoming particularly popular in automotive construction because of their low energy consumption and high life expectancy. The "i-mode", too, is equipped with such LEDs. The job of bundling and focusing the dipped and full-beam light is performed by special collimator lenses made of Makrolon®. "In the production of precision lens systems, polycarbonate has many advantages over glass and PMMA. First of all, it is lighter than glass and does not have to be polished. In addition, the delicate lens geometries can be produced with greater precision and more economically than with processes based on glass," says Dr. Martin Döbler, an expert in plastic optics at Bayer MaterialScience. Compared with PMMA, Makrolon® is not only tougher and more heat-resistant, it also has a higher refractive index. This means that the collimator lenses can be made thinner. Because of the enormous application potential of Makrolon® in LED focusing optics, Bayer MaterialScience has made considerable investments in injection-molding equipment and know-how in this field. "We can now produce components for high-precision focusing optics from special, custom-made grades of Makrolon®. The profile of the light reflected by the optical systems correlates extremely accurately with the simulation of its geometries," says Döbler.
About Bayer MaterialScience:
With 2007 sales of EUR 10.4 billion, Bayer MaterialScience is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction and sports and leisure industries. At the end of 2007 Bayer MaterialScience had 30 production sites and employed approximately 15,400 people around the globe. Bayer MaterialScience is a Bayer Group company.
Information for editors:
Our news releases are available for download from the press server of Bayer MaterialScience AG at www.press.bayerbms.com. More news and information about products, applications and services of Bayer MaterialScience can be found at www.bayerbms.com.
Contact:
Andrea Huber, Tel.: +49 214-30-72536
E-mail: andrea.huber@bayermaterialscience.com
rei (2008-0084E)
Hotline for readers’ inquiries:
Fax: +49 221 9902 160