Largest-ever Rear Quarter Window in SABIC’s LEXAN Resin Debuts on Buick’s New-generation GL8 MPVs

SAIC General Motors (SGM) has launched in China its new-generation Buick GL8 and GL8 Avenir luxury multi-purpose vehicles (MPVs), which sport the world’s largest polycarbonate (PC) rear quarter window, molded from SABIC’s LEXAN resin. SGM is offering five trim levels of the popular GL8 model, which has been a mainstay of the Chinese market since 2000 with more than 700,000 sold.

The new rear quarter window is 40 percent (3kg) lighter and significantly more impact resistant than a comparable glass window. The PC window also features design elements that cannot be achieved with glass, contributing to the more innovative exterior of the new-generation GL8.

SGM chose Ningbo Shentong Auto Decorations as its tier one supplier for this key window part. Shentong, a long-time manufacturer of automotive plastic applications, provided design assistance and technical support across the entire development cycle from concept to validation.

In addition, Shentong invested in a new production facility for PC glazing. This facility is located in Yuyao City, China, and is the first mass production PC glazing line in the country. Manufacturing capabilities include the latest PC glazing technologies, including advanced two-component injection compression molding and flow coating processes.

SABIC worked very closely with Shentong to support development of the window system and enable production readiness. Specifically, SABIC provided technical assistance and transferred expertise to Shentong on part design, process simulation, equipment selection, testing, prototyping and coating.

“This unique window in LEXAN resin meets SGM’s requirements for a lightweight solution, and we are delighted to see it go into production,” said Scott Fallon, SABIC’s automotive business leader. “We are also excited that this window marks the introduction of Shentong’s new manufacturing capability for high volume production of quality polycarbonate glazing parts. We have enjoyed our collaboration with Shentong to help make this possible, and we look forward to more potential opportunities to work with them to bring the benefits of PC glazing to automakers in China and elsewhere.”

The establishment of new PC glazing manufacturing capability in China comes at a time when automakers in the country and across the world are under pressure to adopt lightweight technologies that can help them comply with increasingly stringent emission and fuel economy standards, in addition to improving the driving range of electric vehicles.

“In addition to significant weight reduction, PC glazing allows for greater innovation than is now possible in glass, like design and styling freedom, thermal efficiency and parts integration,” said Jun Luo, Shentong’s deputy general manager. “With our investment in this new manufacturing capability, combined with the benefit of SABIC’s support and expertise, we are now in a strong position to help automakers realize the value from this technology and, ultimately, speed up its wide-scale adoption in the industry.”

The new rear quarter window measures a record-breaking 1200mm by 450mm. It is two-shot injection compression molded at Shentong’s facility, using SABIC’s transparent LEXAN PC resin and CYCOLOY resin, a PC/acrylonitrile-butadiene-styrene (ABS) material (used for the blackout area).

This resin combination helps meet the specific needs of the part’s design and the tight dimensional tolerance requirements of the large rear quarter window. A silicone hard coat protects the part against abrasion and weathering.