Bio-based plastics in the automotive market: clear benefits and strong performance

Bio-based plastics in the automotive market: clear benefits and strong performance

March 28, 2019
Elena Cantos

The automotive sector has, for now, largely escaped the media’s attention in the plastic pollution scandal. What’s as clear for the auto sector as it is for fashion and food packaging, however, with fossil fuels a dwindling resource, the future of plastic lies in its reinvention as a bioplastic

Cutting fuel consumption and emissions by reducing a vehicle’s weight is a central objective and major challenge for the automotive industry and bioplastics materials are well suited to contributing towards this goal. Indeed, leading automotive brands around the world are already using bio-based plastics – such as bio-based polyamides, bio-based polyesters, etc – with the aim of reducing their products’ environmental impact.

In this article, we will focus on available bio-based plastic materials, general benefits of biobased plastics, biobased plastics market development as well as bio-based plastic performance in the automotive sector.

Bio-based plastics comprise a range of materials with differing properties:

  • Bio-based or partially bio-based, non-biodegradable (i.e. durable) plastics such as:
    a) Mass commodity plastics – e.g. bio-based polyethylene (PE), or polyethylene terephthalate (PET);
    b) Bio-based technical performance polymers – e.g. polytrimethylene terephthalate (PTT) or thermoplastic copolyester elastomers (TPC-ET) or bio-based polyamides.
  • Plastics that are both bio-based and biodegradable – e.g. polylactic acid (PLA), polyhydroxyalkanoates (PHA) and polybutylene succinates (PBS), but can also be used in durable applications.

Several bio-based plastics are used in the automotive market, including bio-based polyamides, PTT and bio-based polyolefines as well as PLA-blends.

Benefits of bio-based plastics
Saving scarce resources, counting on renewable feed-stock
Bio-based plastics help reduce the dependency on limited fossil resources, which are expected to increase in price significantly over the coming decades. Renewable resources are gradually substituting dwindling fossil resources. These renewable resources are predominantly land-efficient annual crops, such as corn and sugar beets, castor oil plants, switch grass, or perennial cultures, such as cassava and sugar cane. The latest developments in second-generation products use cellulose as feed-stock basis.

Reduced dependency on volatile energy markets
Bio-based plastics are not as affected by oil price volatility in the way that petroleum-based materials are.

Reducing emissions, tackling climate change
Bio-based plastics contribute to the reduction of greenhouse gas emissions or can be carbon neutral. Plants absorb atmospheric carbon dioxide (CO2) as they grow. Using this biomass to create bio-based plastic products constitutes a temporary removal of CO2 from the atmosphere. This carbon fixation extends for a further period of time if the material is recycled.

Plants absorb atmospheric carbon dioxide (CO2) as they grow. Using this biomass to create bio-based plastic products constitutes a temporary removal of CO2 from the atmosphere

Closing the loop, increasing resource efficiency
Another major benefit is that bio-based plastics can ‘close the loop’ and therefore increase resource efficiency. This potential is realized by establishing use cascades. Renewable resources are firstly used to produce materials and products before being recycled mechanically, where possible. Finally, these resources are used for energy recovery. In this way, the carbon loop is closed.

Detailed Life Cycle Assessment (LCA) data are available for most bioplastics and need to be taken account of when considering end-of-life options.

Bio-based plastic market grows continuously
Currently, bioplastics represent less than 1% of the 335 million tonnes of plastic produced annually. But as demand is rising – and with more sophisticated biopolymers, applications, and products emerging – the market is continuously growing.

In 2018, capacities amounted to approximately 2.11 million tonnes per year. Market data collected by European Bioplastics in cooperation with nova-Institut (Germany) forecasts production capacities to grow by 2023 to roughly 2.6 million tonnes.

Technical applications within the automotive sector are one of the most important upcoming markets for bioplastics. Volumes are expected to increase from around 155,000 tonnes to 166,000 tonnes over the next five years.

Technical applications within the automotive sector are one of the most important upcoming markets for bioplastics. Volumes are expected to increase from around 155,000 tonnes to 166,000 tonnes over the next five years

The automotive industry – counting on renewable alternatives
‘Lightweighting’ is a hot topic for the automotive industry and the main reason why plastics have continuously been used to substitute heavier materials such as metals. Beyond the benefits of reduced weight, the future lies in choosing the most resource-efficient plastics. Bio-based plastics contribute to minimize the environmental impact of car production by further reducing CO2 emissions and energy use. Additionally, materials such as bio-based polyesters or bio-based polyamides feature all the performance criteria to produce high-quality car components.

Major converters and car brands adopt bio-based plastic solutions
A front-runner in adopting bio-based plastics is Japanese car manufacturer Toyota, which uses bioplastics such as biobased polyesters, bio-based PET and PLA-blends in its production process. The Toyota SAI and Toyota Prius models already feature a number of bio-based plastic applications such as headliners, sun visors and floor mats. The Toyota hybrid vehicle Prius Alpha features automotive interior parts made of DuPont Sorona EP polymer, with similar performance and molding characteristics as petroleum-based, high-performance PBT (polybutylene terephthalate).

Furthermore, up to 60% of the interior fabrics are made of bio-based polyesters, which provide mechanical properties equal to or even better than PBT.

Compared to PBT, bio-based polyesters provide a higher stiffness and eature very good dimensional stability and lower warpage. They also boast better thermal shock resistance, provide good electrical properties, are easier to process and provide a better surface gloss.

Italian manufacturer Fiat is another major player in the automotive industry counting on bio-based plastics. In 2011, the use of castor oil-based long-chain polyamide in some fuel lines won Fiat and DuPont the Society of Plastics Engineers’ ‘Automotive Innovation Award’ in the environmental category. Besides bio-based polyesters and polyamides, bio-based PBS converted into a high-performance natural-fiber composite is another relevant material for the automotive market.

Besides bio-based polyesters and polyamides, bio-based PBS converted into a high-performance natural-fiber composite is another relevant material for the automotive market

Bio-based PBS is made of bio-succinic acid and 1.4-butanediol (BDO). It features an interesting thermal-mechanical balance of properties close to that of a polyolefin; it is easy to process and has good affinity with cellulosic fibers. Since 2018, bio-based PBS can be 100% sourced from renewable feed-stock.

Mitsubishi Chemicals is the producer of DURABIO, a partially bio-based engineering plastic made from plant-derived isosorbide, which presents higher resistance to impact, heat and weather than conventional engineering plastics. DURABIO is designed for applications requiring durable transparency and visual appearance with scratch and impact resistance as well as chemical inertness. Renault is the first European automobile manufacturer to choose DURABIO, the French OEM using the material for the dashboard of its Renault Clio.

Moreover, the Mercedes Benz A-class chose the bio-based polyamide DSM’s EcoPaXX Q-HGM24, which is derived from castor oil plants, for the engine cover. This material offers good chemical resistance, low moisture absorption, and a very high melting point to tolerate high temperatures, a high crystallization rate and great aesthetics.

It’s evident that bio-based plastics have reached maturity as a suitable material for a large number of automotive applications, offering high-performance and a unique potential for reducing a product’s environmental impact. It is therefore no surprise that the automotive market is one of the fastest-growing application fields for the bioplastics industry.

European Bioplastics’ Kristy-Barbara Lange, deputy managing director of Regulatory Affairs, is a key member of the Plastic Free World Conference & Expo Advisory Board and has helped craft the automotive and other streams. You will see dozens of materials innovators with solutions to create highly sustainable vehicles at Plastic Free World Conference & Expo 2019. The event will take place from Thursday 27 June to Friday 28 June, at the Kap Europa, Frankfurt Messe, Frankfurt, Germany. To register for this highly focused and solutions-driven event, please click here. For sponsorship and exhibition opportunities, please email peter@trans-globalevents.com

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