Breaking the Bottleneck of Domestic Automotive-Grade Light-Guiding Polycarbonate: Insights into Wanhua Chemical's High-End Materials R&D Strategy

China's automotive industry chain has reached a milestone in the localization of high-end materials. On August 27, Wanhua Chemical and Geely Auto jointly announced the successful domestication of automotive-grade optical polycarbonate (PC) materials, marking a substantial advancement for Chinese companies in the high-end automotive materials sector, which has long been monopolized by foreign giants.

Image source: Wanhua Chemical

This collaboration not only fills the gap in domestically produced automotive-grade optical polycarbonate in China but also provides a replicable successful model for collaborative innovation across the local industry chain.

High-end materials"Stranglehold"Dilemma: The International Competitive Landscape of a Niche Market

Although optical materials for automotive lighting may seem like just a small part of automotive components, their performance directly determines the safety and reliability of intelligent automotive lighting systems. As the optical material for the core components of automotive lamps, light-guiding polycarbonate must meet multiple stringent requirements—it needs to...​High transmittance, low haze, low birefringence, yellowing resistance​Optical "hard indicators" as mentioned above are also required.​High liquidity, high impact resistance, high temperature resistance​The "hard requirements" of physics.

Image source: Wanhua Chemical

For a long time, this niche market has been dominated by international giants such as Covestro, Mitsubishi Chemical, Sumitomo, and Idemitsu, with domestic companies mostly in a follower position. According to industry data, China's overall polycarbonate market relies on imports for high-end products, and the optical-grade polycarbonate segment is even more passively dependent on imports both in terms of equipment and products.

The key distinction between automotive-grade light-guiding polycarbonate and ordinary products lies in its requirement to meet the stringent standards of the automotive industry: a light transmittance of over 90%, passing UV aging tests, and withstanding high and low temperature cycles (-40°C to 135°C) without optical performance degradation or yellowing. These performance requirements pose extremely high barriers to the industrial-scale production of the material.

Technical Breakthrough: From Interface Aggregation Method to Full-Process Independent Innovation

The industrial preparation of automotive-grade optical polycarbonate currently relies mainly on the interfacial polycondensation method, which is significantly more complex than the process for ordinary polycarbonate. This method involves the reaction of bisphenol A (carbon footprint: 4.93 kg CO₂e/kg) with sodium hydroxide, followed by a liquid-liquid interfacial polycondensation reaction with highly toxic phosgene (COCl₂, carbon footprint: 1.39 kg CO₂e/kg). This technological route not only requires strict control of residual small-molecule impurities and extremely high standards of equipment cleanliness, but also necessitates the use of phosgene—a highly toxic and corrosive essential raw material—which demands comprehensive safety measures and exhaust treatment systems. Consequently, both the initial equipment investment and subsequent maintenance costs remain extremely high.

Wanhua Chemical, through its independently developed interfacial polycondensation phosgene process, has made breakthroughs in raw material ratio, additive optimization, and production processes, and has launched the automotive-grade light-guiding PC material Clarnate® LED1355. This material addresses the industry challenge of PC's susceptibility to yellowing by optimizing the polymerization process, significantly enhancing the product's purity and anti-aging performance. Test data shows that its core indicators such as weather resistance, light transmittance, and impact strength all reach the level of imported competing products, with some parameters, such as light transmittance (exceeding 90%), even surpassing international counterparts.

Geely Automotive's technical team simultaneously overcame the challenges of material forming processes. Through precise injection molding and optical calibration technologies, they successfully applied this material to the lighting designs of multiple models including Zeekr and Geely, creating a unique visual effect that blends a sense of technology with Eastern aesthetics. This deeply integrated upstream and downstream collaboration model from the R&D stage significantly improves innovation efficiency and shortens product time-to-market.

Industrial Chain Collaboration: A Demonstrative Case of Building a Local Innovation Ecosystem

The collaboration between Wanhua Chemical and Geely is far more than a simple supplier-customer relationship; it establishes a new paradigm of local industrial chain upstream and downstream collaborative innovation. The success of this model is reflected on three levels:

​​Technical collaboration​Wanhua focuses on breakthroughs in the performance of materials themselves, while Geely specializes in the development of application processes. From the early stages of material research and development, the technical teams of both parties have engaged in deep interaction to ensure that material characteristics and processing requirements are perfectly aligned. This integrated "design-material-process" development model avoids the common issue of disconnection between materials and applications in traditional supply chains.

​​Market Coordination Aspect​This collaboration has made Wanhua Chemical the first Chinese company to enter the core supply chain of light guide grade materials for Geely Automobile's headlights. It also marks another breakthrough following the certification of headlamp lens materials by Hyundai Kia Group, the world's third-largest automaker, in March this year. By adopting high-end domestic materials, Geely has enhanced supply chain security and cost competitiveness.

​​Ecological Collaboration​Wanhua Chemical is accelerating the construction of a full industrial chain layout for automotive materials. On August 21, the company officially signed a strategic agreement with Changzhou Xingyu Co., a leading enterprise in the automotive lighting industry. Both parties will focus on the innovative research and development and application of key materials such as high-performance PC and PMMA, aiming to develop next-generation automotive lighting solutions that meet cutting-edge demands. As a leader in China's automotive lighting industry, Xingyu Co. has an annual production capacity of 80 million various automotive lights, with customers including mainstream automakers such as Hongmeng Zhixing, Chery, Geely, Volkswagen, Li Auto, BMW, NIO, XPeng, Mercedes-Benz, and BYD.

Image source: Wanhua Chemical

Material Matrix: Wanhua Chemical's Automotive Optical Materials Landscape

It is worth noting that Wanhua Chemical is building a complete product matrix of automotive optical materials. Besides PC, commonly used materials for automotive lighting include PMMA, COC/COP, transparent ABS, transparent PP, and transparent PA. Each material has its own advantages: PC is often chosen for headlights (impact resistance), turn signals (high temperature resistance), and dashboards; PMMA is preferred for tail lights (brightness) and ambient lights; ABS is selected for buttons; transparent PP is a cost-reduction option; and COC, as a new material, is considered the future standard for automobiles.

Wanhua Chemical currently has product lines for PC, PMMA, and COC/COP.

In the field of COP/COC, the company launched the WANCOP™ branded product last year. Recently, Wanhua Chemical disclosed a patent titled "A Cyclic Olefin Polymer and Its Preparation Method and Application," which introduces elastomer units with cyclohexyl side groups into the norbornene main chain and adds flexible aliphatic alkyl units onto the side chain polycyclic structures. This endows the COP polymer with excellent mechanical properties while maintaining the superior optical properties and thermal stability of cyclic olefin polymers. In June this year, Wanhua also filed a patent for a "Dual Active Center Metallocene Complex," which can efficiently catalyze the copolymerization of ethylene/α-olefins with cyclic olefins.

Industry Insights: From Breakthrough in a Single Point to Systematic Innovation

The collaboration between Wanhua Chemical and Geely Automobile provides important insights into independent innovation within China’s automotive industry chain.

​​The technical breakthrough needs to focus on core pain points. The biggest technical challenge of automotive-grade light-guiding PC is the yellowing problem after long-term use. Wanhua Chemical has specifically addressed this common industry issue by optimizing the polymerization process, endowing the product with market competitiveness.

Industry chain collaboration is the key to breakthroughs. The industrialization of high-end materials requires not only breakthroughs in the materials themselves but also the synchronous development of downstream application technologies. Wanhua, Geely, and Xingyu have formed a complete innovation chain of "materials - components - complete vehicles" through deep cooperation.

Independent innovation requires long-term investment. Wanhua Chemical's technological accumulation in the field of polycarbonate is not achieved overnight but through years of continuous investment. From ordinary PC to optical-grade PC, and then to COC materials, it reflects the company's step-by-step path of technological breakthroughs.

Standard guidance is of paramount importance. The key distinction between automotive-grade materials and ordinary industrial materials lies in their necessity to meet the stringent standards of the automotive industry. Wanhua Chemical benchmarks international automotive standards throughout its product development process, which is a prerequisite for gaining recognition from OEMs.

With the acceleration of automotive intelligence and electrification, the innovation of automotive materials will embrace a broader space. New applications such as smart car lights and autonomous driving sensors demand higher requirements for materials, which presents both a challenge for Chinese companies and an opportunity to overtake in curves.

Edit: Lily