Are You Ready For: Plastic Windows?

Edward Niedermeyer
by Edward Niedermeyer

As automakers face slowly diminishing returns in their attempts to make internal combustion engines more efficient (while facing huge challenges in electric, hydrogen and other alt-fuel drivetrains), they are looking ever more closely at alternative materials to improve efficiency (and, to a lesser extent, driving pleasure) through weight-savings. Perhaps the biggest emerging trend in this area, especially at the higher end of the market, is in the use of carbon fiber, which is being actively pursued by automakers like BMW, Toyota, Lamborghini and Daimler. But, as WardsAuto points out, there’s another material that’s trying to earn a place in the lightweight cars of tomorrow: polycarbonate plastics.

Polycarbonate windows weigh half as much as glass, and because they are made with injection molding they can come in shapes that can’t be imagined with glass.

However, the material is more expensive. To get auto makers to convert, Sabic and its main material competitor, Bayer MaterialScience, have to sell the idea of integrating other parts into the plastic mold that makes the window.

For example, says Umamaheswara, “on a liftgate, a lot of features can be integrated, and if the manufacturer is short of room in the factory, it can be delivered as a module.”

A modular liftgate could include the window, cladding for the D-pillar, a roof spoiler, the high-mounted rear brake light, a rear wiper foot, handles and logos. When all those processing costs are included, he says, polycarbonate is competitive with glass and metal.

These unique assemblies are just one of the growth areas for polycarbonate plastics. Already, Wards reports that the material has become standard for headlamp covers, and when it comes to high-end, cost-no-object projects, well:

Bugatti developed a targa top for its Veyron 16:4 Grand Sport roadster in both glass and polycarbonate from Bayer, and the plastic version chosen had a weight savings of 13.0 lbs. (5.9 kg)

But that’s not the only project that has seen polycarbonates used to create light-weight windows and lower centers of gravity:

The Smart Fourtwo was the first to use polycarbonate windows, with fixed rear sidelites starting in 1998. Supplier Freeglass has made about 4 million plastic windows for Smart, Mercedes-Benz, the European Honda Civic and the SEAT Leon.

But don’t expect to see many polycarbonate plastic windows or other large subassemblies in many mass-market cars for the next few years. Even though firms like Sabic are coming up with special plastics that, if used on panorama roofs, will not just lower weight but improve insulation as well, they don’t expect major-volume projects until more EVs start coming to market, in the 2014-2015 timeframe. In the meantime, if you’re already raring for some polycarbonate windows, you’ll have to spring for a high-price Euro-spec road-racer like the Renaultsport Mégane R.26.R.

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3 of 40 comments
  • Mharrell Mharrell on Jul 13, 2011

    Am I ready for plastic windows? I've been living with them for a few years already. The stock plexiglass side and rear windows in my KV Mini 1 and my HMV Freeway have held up okay to a little over thirty years of use with only minor scratching and crazing. They're showing their age but don't require replacement. The KV has a glass windshield, so that doesn't count, but the original Lexan windshield in the HMV is doing remarkably well (much better than the adjacent plexiglass, as one would hope), despite no special treatment. I'd like to think that a properly developed modern polycarbonate could do even better.

  • Econobiker Econobiker on Jul 13, 2011

    Forget plastic windows- where the heck are the all plastic pick-up truck beds?

    • C P C P on Jul 23, 2011

      Given the huge market for bed liners, I'd bet they're working on that econo.

  • Tassos I have driven exclusively manuals in my own cars for the first 30-40 years of my driving history. They were usually very affordable, fuel efficient simple vehicles with front wheel drive. Their manuals sucked (in the case of a 1983 GM vehicle I bought new) or were perfect (in my two 5-sp manual Hondas).After 2005, I started driving excellent 5 and 7 speed automatics in my own cars, which were NOT available in the US market with manuals.With today's outstanding automatics, which are also MORE, not LESS, fuel efficient than any manual, your question becomes MEANINGLESS.Because NO CAR "needs" a manual.Only some DRIVERS "WANT", NOT "NEED", a manual.Let us use language PRECISELY.
  • 3SpeedAutomatic And this too shall pass.....Ford went thru this when the model T was introduced. It took the moving assembly line to make real money. As time progressed, it got refined, eventually moving to the Model A. Same kind of hiccups with fuel injection, 4 speed automatic, Firestone tires, dashboards with no radio knobs, etc, etc, etc. Same thing with EVs. Yep, a fire or two in the parking lot, espresso time at the charging stations, other issues yet to be encountered, just give it time. 🚗🚗🚗
  • Art Vandelay 2025 Camaro and Challenger
  • Mike Beranek Any car whose engine makes less than 300 ft-lbs of torque.
  • Malcolm Mini temporarily halted manual transmission production but brought it back as it was a surprisingly good seller. The downside is that they should have made awd standard with the manual instead of nixing it. Ford said recently that 4dr were 7% manual take rate and I think the two door was 15%.