Volume 10, Issue 3 - May/June 2008

Plastic Possibilities
New Glazing Gains a Foothold
by Les Shaver

Editor’s Note: This is the first in a two-part series on the rise in laminate sidelites. The second part will appear in the July/August 2008 issue of AGRR.

In the late 1990s, cars equipped with laminate sidelites were just a gleam in the eyes of auto engineers. There were only a couple concept cars with the glazing then. But times have changed.

And that’s made Pete Dishart happy. The global product marketing manager with the automotive glass and services segment of PPG Industries in Pittsburgh has watched laminates go from concept into reality in more than 40 models. Dishart thinks the number of cars with laminate sidelites eventually will rise to more than three digits. This number could grow even further if the National Traffic Highway and Safety Administration (NHTSA) comes out with a ruling later this year that mandates occupant retention standards that are friendly to laminate sidelites.

“If the features catch on, everybody will try to follow,” Dishart says. “A lot of vehicles getting a lot of attention are using laminate glass and I think we’re getting to that tipping point where adoption could go very quickly in the near future.”

But laminates aren’t the only glazings making inroads into cars. Polycarbonates also are making more and more appearances in concept cars. They soon could be ready for prime time as well.

Laminate Lift-Off
If you look at the trends, it seems that tempered glass won’t be as much of a part of the cars of the future as they have been in the past. Need proof? Look at the Mercedes S Class (which also has an infrared reflective coating to keep the car cool and an advanced acoustic interlayer) where you can find laminated glazing on the windshield, front and rear sidelites, and rear and back quarter glass (see related story in March/April 2008 AGRR, page 18).“Some vehicles have gone laminate all the way around,” says Chuck Butler, business development manager for DuPont Glass Laminating Solutions in Wilmington, Del. “Typically, that’s high-end vehicles.”

Although the other examples of laminate glazing aren’t quite as comprehensive, they’re equally as impressive. Take the Chevy Malibu and Saturn Aura. What do these two cars have in common? It’s simple. They were winners of “Car of the Year” at the last two Detroit Auto Shows. But there’s another similarity, as well. They both have laminate sidelites.

And, those weren’t the only two cars in Motor City featuring laminates. Ford’s new Mustang didn’t win, but it did introduce a complete glass roof at the show (see related story in March/April 2008 AGRR, page 18). The Mustang has a high-tech roof with infrared and acoustic protection. Hyundai has added laminates to its Genesis model.

“The OEMs are seeing the benefits of laminated glass and advanced interlayers growing,” says Tom Laboda, automotive market development manager for Saflex, a unit of Solutia in St. Louis. “[Laminated] has been adopted on all types of vehicles. It performs well. It’s a very durable product. From a market development standpoint, I’m very busy.”

This trend didn’t start in the States, though. “It’s really coming from Europe,” Butler says. “Europe is using a lot of laminated roofs and now it’s coming into North America.”

Now, producers of more moderately priced cars are incorporating laminate sidelites. Subaru is the first producer making laminate sunroofs. “We’re seeing it on a lot more vehicles that are moderately priced,” Dishart says.

That doesn’t mean laminated glazing doesn’t have drawbacks. It is more expensive than tempered, which could cause some trepidation for auto manufacturers looking to incorporate it further in lower-priced cars. Rodger Pickett, vice president for Cindy Rowe Auto Glass in Harrisburg, Pa., sees this as just one of the drawbacks with laminates. “Without legislative mandate, it is difficult for me to conceive increased use of laminated product,” he says. “Not only is it more expensive, but much heavier and the manufacturers are under continuing mandate for average fleet fuel efficiency and vehicle weight is a critical part of meeting those mandates.” 

Polycarbonate Potential
With the exception of those like Pickett, most agree that laminate glazing in cars could be nearing that “tipping point” of which Dishart speaks. But laminated glazing isn’t the only option car manufacturers are studying. Polycarbonates present a lot of potential. “We continue to be very interested in polycarbonates,” Dishart says. “From the polycarbonate standpoint, the primary driver is weight. There’s fuel efficiency with that weight. You want to make sure you have less and less weight to keep the center of gravity as low as possible.”

Although Pickett is skeptical about the impact laminates will really make, he sees great potential for polycarbonates. “Polycarbonates potentially could reduce overall vehicle weight, but quality, scratch-resistant polycarbonates are much more expensive than tempered glass,” he says. Polycarbonates also allow greater design freedom. “It works for different bends and intricate shapes,” Butler says. “You can mold the polymer to that shape as opposed to trying to form-fit glass to that shape.”

But in spite of all of this potential, there are limits. “The issues with polycarbonates are related to durability and cost,” Dishart says. “There’s some more work to be done.”

Right now polycarbonates are limited to fixed windows that don’t go up and down in vehicles. That confines them primarily to quarter windows.

“I don’t believe you will see a lot of use in a moving application,” Hagen says. “It would typically be a fixed location.”

Big Hurdles
You generally don’t see polycarbonates in movable applications because of the scratching issue. Many people think the up-and-down movement in polycarbonate sidelites still causes scratching

“NHTSA is concerned about durability of the parts and scratching in the case of moving parts,” says Thomas Hagen, an engineer covering glass and mouldings for the General Motors Exterior Center. “Glazing is put in a vehicle for the purpose of a clear viewing portal. If the part scratches during normal use, that would be considered an inadequate material for a glazing portal.”

For their part, polycarbonate advocates say these concerns are overblown. John Madej is the president of Exatec, a Wixom, Mich.-based wholly owned subsidiary of SABIC created to develop coatings for polycarbonates. He says its coating system has been tested independently and meets the requirements for moving applications. 

NHTSA has allowed Exatec® 900-coated polycarbonate to be used in vehicle areas specified for Item 2 glazing (safety glazing material for use anywhere in a motor vehicle except windshields), provided that the product satisfies the existing performance standards for Item 2 glazing.

Derek Buckmaster, body panel and glazing at SABIC Innovative Plastics, a Saudi-based global supplier of plastic resins widely used in polycarbonates, says that his company has developed coatings that specifically address the abrasion issue.

“Several car companies seemed to be satisfied that our coatings work,” Buckmaster says. “We’re working toward implementing the manufacturing steps of the Exatec coating system.”

Butler sees even more challenges for polycarbonates. One of these is crazing, which is the development of small micro cracks that develop within the polymer itself. The other issue plaguing polycarbonates for more than decade now has been stiffness and the transmission of noise, the mitigation of which has become the primary impetus for new glazing in vehicles. “Polycarbonates have unique properties,” Buckmaster says. “They’re not worse or better than glass. It’s just different. They transmit less sound at high frequencies and transmit more noise at low frequency, such as road or engine noise.”

Getting the stiffness out of polycarbonates is possible, but then it adds another hurdle. “If you get the same stiffness out of a polycarbonate, you need to be significantly thicker than plain glass,” Butler says. “You get the cost reduction and then weight goes up when you’re trying to mold it to the optical quality that you need.”

Still, polycarbonates are starting to make headway with manufacturers in concept cars. And, like laminate glazing, they played a large role in the cars at the Detroit Auto Show (see related article in January/February AGRR, page 28). The Land Rover LRX concept car on display there has a panoramic roof, sidelites and backlites made from SABIC Innovative Plastics’ Lexan GLX high-performance plastic glazing with Exatec coating technology. The new Lincoln MKT luxury concept vehicle featured lightweight glazing that reduces fuel consumption from SABIC Innovative Plastics’ in its polycarbonate roof panel and backlite.

Polycarbonates also have had some notable successes. 

The Hyundai QarmaQ Advanced Technology Demonstration Vehicle (ATDV) was winner of the International Forum (iF) Product Design Awards 2008 for Advanced Studies. It included panoramic wrap-around glazing using SABIC Innovative Plastics’ Lexan® polycarbonate resin.

“Some manufacturers are making a statement with polycarbonates and they plan to show them on their concept vehicles,” Buckmaster says. “They’re working to write material specifications for polycarbonate glazing or to require glass specifically to take advantage of polycarbonates. It’s essentially the final step.” And, there are some cars on the road now featuring polycarbonates. For instance, the Mercedes GL has polycarbonates on the sunroof working in concert with laminated and tempered glass. 

“When you think about the transition that we’ve seen over the last year and a half to two years, car companies were taking small pieces of polycarbonates, looking at it and waiting to see if something developed,” Madej says. “When you fast-forward to where we are today, Exatec and SABIC are deeply working with OEMs on full vehicle testing.”

But there’s work to be done once polycarbonates take this last step. Polycarbonate producers can’t make a move until car producers commit to their products. Then they need to be sure they can produce enough product to satisfy demand.

“OEMs are doing the specs,” Buckmaster says. “As they make decisions, we will be putting in capital globally to service those segments.” 

Tempered Legacy
Up until the 1950s, the majority of sidelites were laminated. It wasn’t until the 1950s and 1960s that tempered parts came on the scene. “In the 1940s there were many vehicles that used laminate glass for sidelites and now there are none,” says Rodger Pickett, vice president for Cindy Rowe Auto Glass in Harrisburg, Pa. “Auto manufacturers found significant cost savings in the use of tempered and made it the material of choice.”

Other factors led to the adoption of tempered. “Curvature was easier with tempered as well,” says Pete Dishart, global product marketing manager with the automotive glass and services segment of PPG Industries in Pittsburgh.

And, while many people in the industry think laminates and maybe even one day polycarbonates will be the wave of the future, not everyone agrees. Pickett hasn’t been seeing many more cars with laminates coming through the doors at Cindy Rowe. “I wonder if polycarbonates and laminates comprise any greater portion of the market than in the viewable past,” Pickett says. 

Les Shaver is a contributing writer for AGRR magazine.

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