BAYNEWS: 3D lighting for a stylish effect

Tuesday - June 22, 2010

Self-illuminating plastic films for the “Golf GTI nightline” training project by Volkswagen Coaching GmbH

3D lighting for a stylish effect

Leverkusen, June 2010 – The unusual lighting in the interior of the Golf GTI nightline really catches the eye. The project vehicle was designed and implemented by the Automotive Engineering Training department of Volkswagen Coaching GmbH in Wolfsburg as part of an internal training program designed to boost the expertise and motivation of trainees. One special element really comes into its own under the cover of darkness. Various 3D components in the vehicle interior illuminate over the full area and in color when the vehicle lighting system is switched on. An electroluminescent film system based on the polycarbonate film Makrofol� from Bayer MaterialScience has been used to implement this special feature. “In the future, light will play an increasingly important role in the design of vehicle interiors. These components are designed to highlight the wide range of design options offered by our film system for ambient lighting and day and night design in vehicle interiors,” explains Dirk Loof, Global Key Account Manager for the VW Group at Bayer MaterialScience.

For example, the decorative trims in the doors and on the dashboard are equipped with this lighting effect. The trims are printed with a logo, a honeycomb pattern and the red edge trims that have adorned the long-established and now legendary radiator grill of the Golf GTI. In addition to their decorative function, the electroluminescent films are also used for the indirect illumination of the glove compartments and the paneling of the central console.

The exterior of the components is made of a transparent, high-gloss Makrofol� grade. The Functional Films section used a screen printing process to print the film with graphical elements and several layers of various components from the electroluminescent system – such as electrodes and electrically insulating layers – and then used high pressure forming (HPF) to shape the film below its softening temperature. The components were then coated with a self-healing two-component polyurethane clearcoat based on the Desmodur� and Desmophen� range. The special thing about this clearcoat is that it is exceptionally scratch-resistant. Small scratches simply “melt away” in the sun.

Glare-free “3D cold light” over entire surfaces
The inorganic pigments in the non-conducting layers of the film system emit light as soon as a 110 V alternating voltage is applied to the electrodes via an inverter using the on-board power supply. The light intensity can be controlled by the amount of voltage applied. As it is a “cold” light source, it does not emit any heat. The resulting molded parts are maintenance-free and, as such, boast a long service life. This makes light bulbs, LEDs and fiber optics unnecessary and also eliminates the need to replace burnt-out light bulbs. The light generated is also glare-free. Depending on the luminescent pigments used, the light’s color spectrum ranges from blue, green and orange to white. The electroluminescent film system has one big advantage over other comparable technologies – it can be used to produce both two-dimensional components, and three-dimensional components that can be formed into any conceivable shape and that light up over their entire surface, including any curves and edges.

Easy assembly – cost-effective large-scale series production
The process of manufacturing electroluminescent plastic components lends itself to automation. Printing, forming, trimming and, if necessary, back-injecting with thermoplastics such as Makrolon� (polycarbonate) and Bayblend� (polycarbonate+ABS) can take place in a single process step using film insert molding (FIM), a method that is widespread in large-scale series production. The result is complete, fully functional modules that are very easy to assemble. Compared to established methods used to produce backlit plastic parts, far fewer individual components are needed, which in turn reduces the workload for production and logistics. What’s more, the corresponding parts also save on space because the excellent formability of the film system makes it possible to meet the requirements of compact installation spaces.

For the production of facings, which are up to around 40 centimeters long and eight centimeters wide, the Functional Films section has installed a new HPF system for the molding stage. This can be used to process films measuring 500 x 1,000 millimeters. “This system increases the cost-effectiveness of the process further still, because now even more parts can be produced from one film sheet in a single molding step. Moreover, the example of the facings shows that these kinds of system can also be used to mold large film formats without distorting the printed decoration or losing the high gloss of the film surface,” explains Michael Gl�sser, film expert in the Functional Films section.

About Bayer MaterialScience:
With 2009 sales of EUR 7.5 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 the sports and leisure industries. At the end of 2009, Bayer MaterialScience had 30 production sites and employed approximately 14,300 people around the globe. Bayer MaterialScience is a Bayer Group company.

Find more information at www.bayermaterialscience.com.