Sustainable Interiors Tap Plant-Based Materials

Austin Weber // Senior Editor // webera@bnpmedia.com

Bioplastics and natural fibers help automakers address recyclability and lightweighting.

Agave, bamboo, flax, kenaf and seaweed aren’t things that most people associate with automotive interiors. But, that isn’t stopping engineers from using them as ingredients in a new class of eco-friendly materials, such as bio-based foams and trim coverings for center consoles, door panels, floor mats, headliners, instrument panels, seats and other cockpit components.

Automakers and suppliers are scrambling to create sustainable interiors for luxury sedans and electric vehicles. The goal is to create an earth-friendly alternative to traditional interior coverings (synthetic or traditional animal leather), while reducing the use of chemicals and water consumption.

“The biggest benefit of using eco-friendly materials for automotive interiors is that you’re able to recycle the materials, so they don’t end up in landfills,” says Ryan Bailey, head of R&D for the Americas at Continental AG, a leading supplier of surface materials for passenger car interiors. “We can close the loop to ensure we’re doing our part for the Earth.

“That’s the huge ‘why’ of using these types of materials,” explains Bailey. “One surprising benefit is that a lot of these materials create exciting new textures or designs that we wouldn’t have otherwise thought of. An example of this is the thermoplastic polyurethane monomaterial artificial leather that incorporates post-industrial polyurethane waste into the film, which creates a speckled surface appearance not possible with standard materials.”

Continental has developed a variety of products that feature recycled or eco-friendly raw materials. Some applications include cut and sewn interior parts, such as instrument panels, trim parts, seating and bolsters. It has also developed thermoformable materials for door panels, seat back panels and instrument panels.

“[We are] working with customers to develop eco-friendly surface materials for most applications in each of the product lines,” says Bailey. “The guiding principle behind the development is the reduction of the product carbon footprint (PCF), which is a measure of the carbon dioxide (CO₂) associated with the life of the product from raw material creation to end of life.

“Our Benova polyurethane artificial leather product family has a new member, EcoProtect, which has nearly a 25 percent reduction in PCF,” claims Bailey. “Acella polyvinyl chloride artificial leather, an eco-friendly material already in serial production, has a reduction of 30 percent.

“With Xpreshn polyolefin thermoformable materials, a foam laminate construction is already available that has a PCF of almost zero,” adds Bailey. “That’s the first target for all materials where there is no negative carbon dioxide impact.  

“We see bio content being used for a variety of trim surfaces, including seats,” notes Young. “Many different subassembly components go into a trim cover assembly or a foam pad assembly. Just the amount of dissimilar materials in those components makes them very difficult to recycle at a vehicle’s end of life. So, unfortunately they end up as waste in landfills.”

To address those issues, Magna engineers recently developed a new line of products called EcoSphere that combine sustainability with performance. They feature monomaterial polyethylene terephthalate with 100 percent melt recyclable foam.

“You can take those components off and turn them over to a recycler that can mechanically grind it up, melt it down and create new polyester fibers,” says Young. “That creates a circular economy that can be used over and over again. Currently, it’s too difficult to disassemble a seat at a vehicle’s end of life.

“The EcoSphere product line focuses on the trim cover assembly, the trim foundation, the base pad assembly and structures,” Young points out. “This enables our seating materials to be repurposed and reused in the creation of new polyester products, contributing to a circular economy approach. Our technology offers automakers a game-changing opportunity to enhance sustainability without compromising comfort, quality or performance.”

Aside from cost, one challenge faced by Magna’s engineers was ensuring that the performance of these products meets or exceeds automotive-grade specifications. To address that issue, they looked beyond material specifications and ran products through complete seat testing to make sure that all functional objectives were still being met, such as comfort, durability and safety.
“Typically, seats are assembled with clips, hook-and-loop fasteners, or hog rings to tie trim covers down to the foam pad assembly,” says Young. “We developed a way to continue using that same exact process, but do it in a sustainable way. With EcoSphere, we still keep those components attached and don’t have to worry about disassembling them. Because everything is monomaterial, it can all get recycled as a single assembly component.“

EcoSphere is not currently in any production vehicles, but we are working with several OEMs to get it launched,” explains Young. “It will be available within the next year or two. We’re also trying to determine where else this technology can be used in other automotive applications.”

European Influence

European automakers are leading the charge to sustainable interiors, due to strict environmental rules, such as end-of-life recyclability legislation. That’s why brands ranging from Audi to Volvo are unveiling green alternatives.

“The customer base targeted by EVs are excited about opportunities to do their part in good stewardship of the world for future generations,” explains Bailey. “This group of customers also generally are willing to pay the cost associated with leading the way on vehicles containing eco-friendly materials.”

“There is a growing global demand for integrating bio-based materials as automotive OEMs respond to consumer expectations and regulatory pressures to decarbonize vehicles and embrace circular consumption models,” adds Per Mårtensson, Ph.D., chief revenue officer at Bcomp Ltd., a Swiss company that specializes in lightweight materials made with flax fiber.

“Natural materials are extremely efficient when used and applied in the right way,” claims Mårtensson. "Flax is an easy-to-care-for and highly robust plant that has been used as a raw material for linen in the textile industry for millennia.”

Today, 75 percent of the world's scutched flax fiber is cultivated in western Europe. BComp’s natural fiber materials are already used in Cupra, Polestar and Volvo vehicles. In 2023, the Volvo EX30 compact electric SUV became the first production vehicle to use BComp’s ampliTex fiber composites for its dashboard and doors. The Polestar 3 is an electric SUV that also uses the robust flax-based material for various interior trimmings, such as seat backs.

“Compared to conventional plastic trim, this can save more than half of the petroleum-based raw materials,” says Mårtensson. “Additionally, the material shines with its unique lightness and enables reduced vibrations."

“However, the issue of consumers’ general unwillingness to pay a premium for vehicles containing less plastic and more bio-based or recycled materials is compounded by the fact that plastics benefit from highly optimized and cost-effective supply chains rooted in linear consumption,” adds Christian Fischer, CEO of BComp. “[That is] without factoring in the environmental costs of landfilling at the end of a vehicle’s life.

“[Our products] address this gap by offering added value, such as lightweight design, high-performance and customization, enhancing the demand for bio-based materials, despite cost pressures,” notes Fischer.

“In [our] experience, this growing trend is most pronounced in Europe, where bio-composites are helping OEMs meet increasingly stringent regulatory standards aimed at reducing carbon footprints, improving recyclability and adhering to end-of-life vehicle directives,” says Fischer. “While the trend toward sustainability has been evident for years in Europe, it is now gaining traction worldwide, with increasing interest in the United States and Asia.”

“A company with Ford’s scale can really influence the supply chain and business practices across our entire industry,” adds Sue Slaughter, purchasing director at Ford Motor Co. “It is so important that we not only think about how [we] can use our purchasing power to fuel our business needs, but also to advance sustainability.”

Because the automotive supply chain is extremely complex, the Guiding Principles contain expectations about business ethics, working conditions, human rights, health and safety, environmental leadership and supply chain due diligence for suppliers at all tiers. All suppliers are expected to uphold these standards and enforce them throughout their supply chain.

The Guiding Principles are based on fundamental elements of social, environmental and governance responsibility that are consistent with applicable laws and international standards created by organizations such as the United Nations.

Topics covered under the revised guidelines include the following:

        Business ethics, including counterfeit parts and data protection.

        Environmental issues, such as air quality, carbon neutrality, chemical management, circularity and water management.

        Health and safety issues, such as personal protective equipment and workspace.

        Human rights and working conditions, such as benefits, wages and working hours.

        Responsible supply chain management, such as ethical sourcing of raw materials.

The BMW Group has implemented several projects in its packaging logistics unit to help the environment and conserve resources. The goal of the initiative is to work closely with suppliers to reduce carbon emissions and adhere to the principles of a circular economy.

BMW’s European assembly plants are using more recycled material in their packaging. For newly awarded contracts, the proportion of recycled material in reusable packaging for logistics purposes will almost double this year from around 20 percent to over 35 percent.

Using alternative sustainable materials, reducing single-use packaging, introducing lightweight packaging in certain areas and reducing transport volumes will also help cut carbon emissions.

BMW is monitoring the impact of individual measures via a CO₂ calculator for packaging. The automaker’s overall aim is to reduce CO₂ emissions in the supply chain by 20 percent per vehicle compared to 2019.

“Our re:think, re:duce, re:use, re:cycle approach is being implemented consistently in packaging logistics,” says Michael Nikolaides, head of production network and logistics at BMW Group. “We’re using innovative strategies to consistently reduce the volume of resources we use, thus reducing our carbon footprint.

“We are also doing our part to get the BMW iFACTORY up and running, with a particular focus on the ‘green’ side of things…with an emphasis on flexibility and efficiency, sustainability and digitalization,” explains Nikolaides. “It provides an answer to the challenges involved in the transformation to e-mobility and [leverages] the latest technologies to create a production process that uses minimal resources.”

According to Nikolaides, BMW is using more recycled material, such as expanded polypropylene (EPP) packaging. “Our newly developed EPP packaging already contains 25 percent recycled material,” he points out. “EPP is used in special containers, as its shape can be adapted to the components being packaged, allowing them to be transported safely.

“Around 360,000 of these containers are needed each year,” claims Nikolaides. “Using 25 percent recycled material allows us to save almost 280 tons of CO₂ annually. There are plans to increase this proportion of recycled material even further, with the first pilot schemes with 100 percent recycled material currently underway. If these tests are successful, this configuration will become standard for new contracts from 2024.

“An additional 680 tons of carbon emissions savings can be made every year by using covers and so-called small load carriers with 50 percent recycled contents,” says Nikolaides. “As things stand, these measures are focused within the European markets due to the current waste management situation and available recycling infrastructure. But, we are working toward expanding to our locations in China, Mexico and the United States.”

BMW also plans to use folding large load carriers in place of traditional pallet cages made of steel. The plastic alternatives will be made from over 90 percent recycled material. They work in a similar way to the collapsible shopping crates that most people are familiar with.

When they’re empty, the carriers can be folded up, making them easier to transport. Nikolaides claims that using 15,000 of these new containers will reduce CO₂ by around 3,000 tons per year.

“When it comes to packaging, the sky’s the limit,” says Nikolaides. “We’re launching pilot projects using bio-based materials to replace oil-based substances such as polyethylene and polypropylene.

“We are also investigating whether and in what ways we can use materials from recycled household appliances in our packaging,” explains Nikolaides. “In the long term, our aim is to use alternatives to raw materials across the board.”