Polycarbonate Elevates Aesthetics, Durability of Paint-free Auto Exteriors

Sabic has added a new resin to its weatherable LNP SLX polycarbonate (PC) copolymer portfolio. The speciality material — LNP Elcres SLX1271SR — features enhanced scratch and mar resistance and a high-gloss surface finish to provide the automotive industry with a new molded-in color alternative for exterior components. The LNP Elcres SLX1271SR resin also reportedly delivers exceptional weatherability, continuous UV stability, and good mechanical performance.

By adopting this new solution, customers can leverage the environmental and potential system cost advantages of paint elimination while maintaining the attractive appearance of exterior parts over time. The resin is a 2024 Edison Best New Product Awards finalist in the Advanced Materials category. The Edison Awards honor global innovation excellence.

“Our latest technological breakthrough increases the appeal of paint-free thermoplastics by resolving the downsides of traditional materials, such as scratch-resistance issues,” said Jenny Wang, director of Formulation & Application, APAC, Specialties, at Sabic. “Innovations such as our intrinsic UV absorption layer help this new resin maintain its gloss and mechanical performance over the life of the vehicle. New LNP Elcres SLX1271SR resin demonstrates our technical team’s ability to develop creative solutions to our customers’ toughest challenges.”

Reducing VOCs in automotive manufacturing

When considering a typical vehicle’s life cycle, studies have shown that as much as 95% of volatile organic compounds (VOCs) are emitted during the painting process. Although the automotive industry is turning to solutions with a lower environmental impact, such as waterborne paints, many of these products still emit some VOCs. Therefore, many manufacturers rely on thermoplastics with molded-in color to avoid VOC emissions and costly secondary operations. However, some of these materials have difficulty maintaining their original aesthetics, such as color depth and gloss, when exposed to abrasion, impact, harsh weather, and UV light.

Paint-free LNP Elcres SLX1271SR resin offers a new solution for reducing VOC emissions in automotive exterior components, while delivering aesthetics comparable to painted polycarbonate (PC) and PC/acrylonitrile-butadiene-styrene (PC/ABS) resins. For instance, in terms of scratch resistance and gloss retention, this new product showed similar performance to painted polymer substrates in the wet scrub (car wash) test. Further, the Sabic material can maintain its desirable aesthetics better than other paint-free thermoplastics – for up to 10 years or more, according to the company. One reason is that the resin forms a self-protecting layer that absorbs UV light on a continuous basis to help retain color and gloss.

Vivid molded-in colors include piano black

“We continue to evolve our LNP portfolio with new solutions that can extend the useful life of end applications,” said Maureen MacDonald-Stein, director, Portfolio Strategy & Marketing, Specialties, Sabic. “Customers increasingly favor thermoplastics with molded-in color to avoid coating operations that release volatiles into the atmosphere. Understandably, they do not want to compromise on durability or aesthetics. Our new paint-free LNP SLX resin supports VOC reduction while meeting all key requirements for a beautiful long-lasting and resilient finish.”

LNP Elcres SLX1271SR resin is formulated to deliver vivid, molded-in colors, such as piano black, and a high-gloss surface finish. In a comparison with competitive materials — a toughened PMMA grade and a blend of PMMA and acrylonitrile styrene acrylate (ASA) — the results showed that LNP SLX1271SR resin provides better mechanical performance as well as improved gloss, color depth, and heat resistance (~120℃), according to Sabic.

This new scratch-resistant grade extends Sabic’s weatherable portfolio, which encompasses a range of high-gloss, opaque colors as well as clear or tinted transparent colors. In addition to automotive exterior parts such as spoilers, grilles, and mirror housings, it is suited for computer electronics housings and outdoor infrastructure components such as solar panels.