Q&A with SABIC’s Innovative Plastics: Polycarbonate glazing

By Matthew Beecham | 17 February 2014

Scott Fallon

Scott Fallon

Alongside the enthusiasm amongst car designers for more glass, pressure to produce more complex glazing shapes and styles is also driving up interest in alternative polycarbonate (PC) glazing technologies.  We wouldn't call it a gold rush but we continue to see a steady stream of interest in PC glazings for certain applications. To find out how this market is shaping up, Matthew Beecham spoke to Scott Fallon, general manager, Automotive, SABIC's Innovative Plastics business.

PC glazing has been used in Europe for some time yet we have heard that the prospects for PC in the Chinese market are good, too. What is your view?

We are excited about the prospects for SABIC's PC glazing solutions in China. OEMs in the country are enthusiastic about the technology. One reason for the enthusiasm, we believe, is that Chinese OEMs are eager to differentiate their vehicles both at home and abroad. PC glazing offers tremendous potential to help them with that task because of the design freedom and styling opportunities it makes possible.

What are the best vehicle applications for PC glazing today?

Rear quarter windows are a good place for automakers to start, and many are in production today, including the Citroën DS5 and the Fiat 500L. PC glazing is also a great candidate for applying to front quarter windows, roofs and spoilers.

One window application that holds tremendous potential is the backlite. This is an application where automakers can strive to take advantage of all benefits made possible by PC glazing.

SABIC's all-thermoplastic tailgate concept, launched at last year's K Show uses our PC glazing materials for the backlite. Using SABIC's Lexan resin and Exatec coating technology on a backlite can further enhance the design freedom and help to increase the total weight that an automaker can save. A second shot of black out material is applied on the backlite panel using Cycoloy XCM resin, which can help expand the possibilities for integrated functionality, such as the fixing for rear lighting, antennas and cameras.

Is PC glazing particularly apt for electric vehicles in terms of weight, despite the extra initial cost?

With an electric vehicle, there is still a need for weight reduction, particularly with the addition of heavy battery packs and other EV content. Use of PC glazing solutions can help to offset the added weight.

Speaking of cost, we know it's an important consideration for everyone. An important point to bear in mind is that PC glazing gives automakers much more overall value when compared to glass. By applying PC glazing instead of glass, not only can automakers save weight, which can contribute to extended range for an EV or improved fuel economy for petrol-powered vehicles, but they can also realize benefits from improved aerodynamic efficiency, better thermal management and greater design and styling possibilities.

Also, with PC glazing, there are new possibilities for parts integration, which has the potential to lead to further overall cost savings. All of those benefits represent a substantial cost offset when viewed at the total system cost level.

Is it easier to integrate an antenna into a PC piece over glass?

We are excited about the integration of antennae into PC windows. SABIC has developed technology to enable direct printing of antennae structures on the inside surface of roofs and side windows with PC glazing. The PC material allows for good signal reception and a small footprint on the windows.

How does PC compare to glass as a thermal insulator?

It compares very favourably. In fact, PC's thermal conductivity is up to five times lower than glass, which can contribute to improved thermal insulation of the passenger cabin in a vehicle. There can also be less heat build-up in a vehicle with PC glazed windows. Thermal improvement measures will vary depending on vehicle-specific design factors, including the size of the window area made with PC glazing.

Is it possible to use PC in place of glass for winding glasses?

Yes. Volkswagen produced the fixed and roll-down side windows of its XL1 diesel plug-in hybrid through a two-shot (2K) injection compression moulding process using PC materials from SABIC - our Lexan and Cycoloy resins, and our Exatec plasma coat solution for high quality aesthetics and scratch resistance. Use of PC glazing for the XL1 side windows resulted in a 33 percent weight saving compared to conventional glass solutions.

These are the first fully homologated PC roll-down windows produced using 2K injection compression moulding that meet VIII/B/L ECE R43 requirements. We know of no other PC glazing solution commercially available today that can enable automakers to meet these requirements. So yes, it's possible to design moving windows to take advantage of all benefits PC glazing can offer.

In what ways would you like to see Regulation 43 (for safety glazing) be changed and updated, perhaps taking account of the technical advances made in the PC glazing arena?

The remainder of this interview is available on just-auto's QUBE research service