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27 July 2023

Sustainable Polyurethanes in Automobiles: Addressing the Whole Lifecycle of PU Parts

At our last conference in Budapest, EURO-MOULDERS presented a report aimed at a non-specialist audience on ways to improve the sustainability of polyurethane foam in the automotive sector. The following article summarises the main conclusions of the study, while providing important context on the usage of PU in automotive and changes in the upcoming legislation regarding the mandatory inclusion of recycled content. 

Polyurethanes: A Material of Choice in Automobiles

Polyurethane (PU) is widely used in the automotive sector in a variety of applications: from seating and armrests to headliners and dashboards. On average, a passenger car or light commercial vehicle contains up to 28 kilograms of PU, making it the second most used plastic in the sector. It is also increasingly used in both Internal Combustion Engine (ICE) cars and electric vehicles (EVs) to enhance comfort, fuel economy, and user experience – notably as regards acoustic insulation. In addition, the use of PU in EVs is growing in battery packs and for improved thermal insulation, allowing to save energy and thus increasing the range. 

To gain a better understanding of the opportunities and challenges that PU may face in automobiles in the foreseeable future, in 2021 EURO-MOULDERS published a study Polyurethanes in Automobiles – Horizon 2030. The main takeaway is that polyurethane will remain the material of choice towards 2030 for most applications in cars and other vehicles it is currently used in, and – due to the electrification of vehicles – it is expected that in some areas its market share will increase. However, as is the case with all plastics, interviewed stakeholders expressed the opinion that the circularity and sustainability of the product needs to be further improved, notably by reducing dependency on fossil feedstock and including more recycled content.  

Upcoming Legislation: New Rules for Recycled Content & EPR Schemes 

With the new proposed End-of-Life Vehicles Regulation, The EU plans to promote more circular business models and better recycling efficiency. Changes include mandatory recycled content rules for plastics used in cars and greater / more harmonised deployment of Extended Producers Responsibility (EPR) schemes for the automotive sector. The focus is on preventing downcycling of materials and promoting value-retention practices like remanufacturing.

The integration of recycled content in plastics, considered under the proposed End-of-Life Vehicles Regulation, is just one way of making polyurethane more sustainable. By working all along the lifecycle of the material, it is perfectly possible already today to use polyurethane with a lower carbon footprint in vehicles.

Improving the Sustainability of Polyurethanes in Automotive: A Holistic Point of View

The overall impact of PU in the lifecycle of a car is relatively small. Although extensively used in automobiles, polyurethane components account for less than 1% in terms of the car lifecycle GHG emissions. However, if we look at this from a holistic perspective, as the recently published EURO-MOULDERS’ study ‘Improving the Sustainability of Polyurethane Foam in the Automotive Sector’ details, there are several ways for making PU more sustainable. The analysis conducted in the report suggests that the industry needs first and foremost to focus on the raw materials that PU is made from, as they have the most significant environmental impact.

  • Substitution of Fossil-Based Feedstock

Technologies to make low-carbon or more sustainable polyurethane parts have progressively found their way onto the market for many years, specifically by reducing dependency on fossil-based feedstocks. Regarding polyols, there are several alternative technologies available. The first one is by using biomaterials – also called Natural Oil Polyols (NOP’s) – as feedstock. These range from castor, rapeseed or soybean oils, amongst others. More recently, recycled polyols coming by the means of depolymerisation from end-of-life mattresses are also available on the market. Both alternatives have been tested and tried in various applications in the automotive sector. The current issue is that non-virgin polyols can only be used in relatively small fractions in foam formulations without losing quality. As the technology keeps developing, the expectation is that the proportion of recycled polyols will increase in the future. 

Another solution is integrating recycled content from mechanical recycling such as for example rebonded PU foam. As we speak here of using materials with reduced physical and mechanical properties, this is only suited for a limited number of (non-visible) parts, especially in a  supply chain with stringent specifications, such as the automotive sector. 

  • Integration of Recycled Content in PU in Automotive Via Mass Balance Approach

The main way of integrating recycled content in PU for automotive applications is via the mass-balance approach (MBA). An increasing number of such raw materials and PU parts made with these materials are already on the market. 

The approach is basically a process methodology (bookkeeping) that allows to track how much of a bio-based, bio-circular or recycled feedstock is used in the production of virgin chemicals. This is important because the end-molecules produced are the same, no matter what the feedstock used.

Mass balance raw materials have the advantage of allowing the production of polyurethanes with a lower carbon footprint or recycled content, while still being of the same quality as traditional, ‘virgin’, raw materials. This is essential in a supply chain with very high specifications such as the automotive one. As the materials produced are essentially the same as with fossil-based feedstock, mass-balance raw materials are also easy to process with existing technology and do not require lengthy and expensive requalification of parts made using them. 

  •  Working on Eco-design of Car Parts for Easier Dismantling and Recycling

Polyurethane from end-of-life vehicles is seldom recycled today, although PU is perfectly recyclable. Similarly to many other  materials from ELVs, this is due to the difficult and costly recovery of the material once integrated in complex car components. The supply chain needs to work on the eco-design of car parts for easier dismantling and removal of parts before shredding. Better eco-design of automotive parts will enhance recycling and recyclability of PU, both mechanical and chemical. 

What Needs to be Done?

Implementing sustainable solutions requires collaboration between the whole automotive value chain; from raw material suppliers, polyurethane parts and automotive manufacturers, to policymakers and recyclers. They all must work together to foster innovation and expedite the development, scaling and adoption of the analysed solutions.

  • Supply chain needs to make greater use of novel raw materials that are coming onto the market. 
  • Regulators should create a framework that encourages investments. Imposing recycled content is a good way to create a level playing field and create a market for recyclate. However, by restricting recycled content to post-consumer plastics only – as the current draft of the ELV Regulation published in July 2023 proposes – important recycling streams including from automotive applications would not be qualified to provide recycled content and therefore promising routes (recycling oils, tyres…) may not be pursued.
  • Recycling of plastics from cars remains an issue. This requires thinking at two levels: car design and how ELV’s are handled. Some companies are also working on technologies to handle Automotive Shredder Residue (ASR) to minimise need for handling and find better economic balance, but there again we come to the same question: the need for a market and level playing field for recyclates, the need for acceptance of chemical recycling and an open attitude towards the origin of post-consumer recycled content.

All things considered, to effectively reduce the environmental impact of polyurethane in vehicles, an ecosystem-based approach is necessary. Manufacturers of polyurethane need support from both upstream suppliers and downstream users to create a pathway towards a more sustainable future. The main solution currently is by replacing fossil-based feedstock with novel low-carbon or more sustainable raw materials. It would be great if in the future part of that sustainable content would be from cars, but for that regulators, the supply chain, and recyclers all have a role to play.