A CHINESE OR INDIAN AUTO MAKER could be the first to go for plastic car windows in a big way, says an executive at Sabic Innovative Plastics.

“In China and India, they are not tied to an existing infrastructure,” says Venkatakrish Umamaheswaran, director-automotive products and marketing.

“A lot of industry technology that requires a new way of thinking is well-received” in those emerging markets, he adds.

The technology in question is polycarbonate glazing, and Sabic is investing heavily to get ready for a breakthrough it hopes will arrive soon, thanks to the pressure to improve fuel economy.

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.

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

What is not in question is the weight savings. 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).

Hyundai's HED-4 concept used polycarbonate for its backlite, sidelites and roof, cutting weight 38.1 lbs. (17.3 kg).

Plastics Europe, an industry organization, says 31-49 lbs. (14-22 kg) of carbon-dioxide emissions are saved for each 2.2 lbs. (1 kg) of polycarbonate used on cars over their lifetime.

Sabic this year added capacity for polycarbonate in a Saudi Arabian plant, and in May it signed a memorandum of understanding with its Chinese joint-venture partner, China Petroleum & Chemical, to build a new facility in China with a polycarbonate capacity of 260,000 tons (236,000 t) a year beginning in 2015.

Sabic also has invested in its U.S. Glazing Technology Development Center in Wixom, MI, to rebuild a pilot production line. That project involves Exatec, the subsidiary for developing automotive polycarbonate, and a partnership with the Japanese tool maker ULVAC.

The partners are creating tools enabling Tier 1 suppliers to manufacture high-volume polycarbonate glazing with a plasma finish that puts a protective layer of silicon on the softer plastic.

Polycarbonate has become standard for headlamp covers, and auto makers frequently experimented with the material in the early half of the 2000s.

The Smart Fortwo was the first to use polycarbonate windows, on 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.

Sabic expects polycarbonate will find a place on high-volume projects that need to improve fuel economy. The company has a new selling point: the insulation factor of plastic, when treated with resins that absorb near-infrared light waves.

Matteo Terragni, Sabic's segment manager for automotive glazing in Europe, says if plastic glazing is used on a panoramic roof and backlite of a moving car instead of glass, it will reduce the need for heating in winter and cooling in summer by 9° F (-13° C) in extreme climates.

“The reduced demands on climate control have the same benefit as the weight savings (on fuel economy),” he says. “We now show a double advantage.”

The light weight and insulation factors also are critical to electric vehicles, allowing them either to increase range or use smaller, less-costly batteries.

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