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Sustainabilit yFossil Raw Material Replacement –Demanding Vehicle Components fromSustainable Polyamide
The aspects of a sustainable circular economy and bottlenecks in supply chains are leading thechemical and automotive industries to increasingly develop and implement strategies for using­secondary raw materials. Against this background, Mercedes-Benz, BASF, WITTE Automotive andPyrum developed an external door handle made of a more sustainable, mass-balanced polyamide.
Pyrolysis oil from scrap tires and biomethane from waste in the agricultural and food industry is
assigned as raw material base to the certified product instead of fossil raw materials.

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W R I T T E N BY

Oliver Geiger
is Sustainability Expert for
Plastics Applications in theAutomotive Industry at BASF SEin L­ udwigshafen (Germany).

Daniel Braunis Project Manager
for Future Materials
at Mercedes-Benz AG
in Böblingen (Germany).

Eleni Kougioumtzi
is Expert for Resource-saving­M aterials at Mercedes-Benz AG in
Stuttgart-Untertürkheim (Germany).

© BASF | Mercedes-Benzg With the Green Deal, the European

Commission aims to achieve climate neutrality in the EU by 2050 by reducing
Greenhouse Gas Emissions (GHG) to net
zero. The transition into regulation for
individual economic sectors occurs via
industry-specific directives covering theproduction, use phase and end-of-use
product recycling.
In 2021, the EU Commission’s evaluation of recycling components and materials in vehicles at the end of their life
per the EU End-of-Life Vehicle Directive(Directive 2000/53/EC) [1] will result ina revision in this directive. This review
includes a stricter definition of material-related recyclate quotas and a regulaATZ worldwide

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tion of measures for closed materialcycles. A draft of the revised directive
is expected in the course of the year
2023, with adoption by 2025, at the latest, and then translation into nationallaw. As a result, resources are to be conserved and thus also the emission ofgreenhouse gases during the productionof vehicles is to be reduced.
This revision poses significant challenges also for the plastics processing
industry. Industry experts expect thatthe use of mechanically recycled plastics
will not be sufficient to meet the requirements. For safety-relevant plastic com­ponents with high mechanical requirements or for applications in vehicle inte-riors with correspondingly low ­emission
limits, high requirements regarding
odor, absence of pollutants and fogging,high-quality plastic recyclates will (presumably) not be available in the required
quantities. This situation is true if therecycled plastics are not produced basedon production waste (post-industrial orpre-consumer) but are to come fromso-called post-­consumer waste.
Challenges also arise in the closed
loop of plastics from end-of-life vehicles. These concerns are mainly dismantling and sorting but also preparing plastic components into reusable
products. Only limited quantities ofhigh-quality plastic recyclates are29

C OVER STORY

Sustainabilit y­ ossible with today’s standard shredp
ding and processing technologies. Al­­
though research ­projects deal with
developing these ­technologies further, cost-efficient recycling of engi­
neering plastics will need to extend
beyond mechanical processing techniques. Added to this is the fact thatthe plastic recoverable from end-of-life
vehicles has been in use for an averageof 17 to 18 years and has thus aged significantly more than is the case withpackaging products with a short periodof use [2].
Therefore, chemical recycling tech­
nologies are additionally being discussed, and numerous companies are
already promoting their developments
and commercialization, FIGURE 1. Therefore, experts from VCI, Dechema andPED advocate the practice of mechanical and chemical plastics recycling ascomplementary recovery routes. Depending on the plastic quality and compo­
sition, different technologies can beadvantageous. In order to identify thebest recycling routes, waste management and the chemical industry must
work closely together [3].
CHEMCYCLING, PYROLYSISOIL AND MASS BALANCE

In the chemical recycling of plastics bypyrolysis, the plastic molecules are split
at elevated temperatures (300 to 700 °C)

under ab­­sence of oxygen. The resulting
pyrolysis gases are condensed into pyrolysis oil by a controlled cooling. In the socalled ChemCycling, the pyrolysis oilthat meets specifications is then reintroduced into the chemical production network, for example, for plastics production and replaces fossil raw materials
up to a certain percentage.
With various cooperation partners,
including the companies Pyrum andQuantafuel among others, BASF hasadvanced the pyrolysis of used tires andplastic waste which are unsuitable for amechanical recycling for technological,
economic, or environmental reasons.
The pyrolysis oils obtained in this way
are commercially used today and converted into chemical products, including
engineering plastics, at the Verbund site
in Ludwigshafen (Germany).
The pyrolysis oil quantities currently
already used at BASF pass through ex­­actly the same production lines as thethe fossil raw materials and are allocatedto the chemical sales products purely
virtually according to the mass balance
approach, FIGURE 2. This so-called attribution principle is similar to the logic
of green electricity contracts: Some customers purchase only green electricity
according to an agreement, while allreceive a randomly composed electricity mix. This distinction does not affect
the generation and distribution of electricity via the electricity grids. Only anaccounting allocation and settlementtake place in the defined balance area.
It must be demonstrably ensured thatenough green electricity is introducedinto the balance area to supply the­existing green electricity ­customers
accordingly.
Similarly, in ChemCycling, the massbalance approach is applied in order toproduce mass-balanced materials using
secondary raw materials in parallel toconventional materials without installing entirely new production facilities.
Instead, only minor adjustments are­necessary to use the pyrolysis oil on
existing plants. The allocation of raw
materials to sales products as well as
the compliance with the mass balanceof the ChemCycling products is audited
and monitored by recognized certification schemes such as RedCert² or ISCC+.
Mass-balanced plastics have thesame properties as conventionally man­ufactured products, can be further processed in the same way, and can be usedin demanding applications. This approach
applies equally to ChemCycling products
based on pyrolysis oil from plastic pyrolysis and to the Biomass Balance (BMB)
products described in the following,with biomethane attributed to the massbalance as the source of raw materials.
The availability of pyrolysis oil is currently still limited. In addition to BASF,
numerous companies in the chemicaland petroleum industries are investing

FIGURE 1 From linear to circular value chain at BASF: classification of recycling technologies (© BASF)

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FIGURE 2 Mass balance approach in BASF’svalue chain (© BASF)

in developing and expanding capacities[4, 5] to meet rising demand.
RENEWABLE RAW MATERIALSAS A SUBSTITUTE FOR
FOSSIL RAW MATERIALSIn addition to pyrolysis oils, renewable
raw materials are increasingly used as
secondary raw materials in chemicalproduction. However, this requires
their sustainable production, especiallyregarding land and water consumption
and protecting areas with high biodiversity. In principle, chemical industries
must minimize the resource competition with the food production. Therefore,
renewable raw materials from organic
waste from agricultural or food production are preferably used.
Waste-based biomethane has an enormous potential, which also attributes
to chemical products according to themass balance approach and can thus
replace natural gas proportionately intheir manufacturing. According to EU
RED [6], biomethane is certified con­cerning its origin.
The currently produced quantities ofbiogas are only partially purified into
biomethane and used as a raw material
to produce chemical products such as
plastics, FIGURE 3. However, a trend
reversal from biogas power generation
toward purification and feed-in into
the existing gas infrastructure can be
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observed. Furthermore, there is a signi­
ficant increase in capacities for biogas
production to utilize the organic waste
streams from the agricultural and foodindustry, which still need to be fully
used.
EX AMPLE OF A DOOR HANDLE:POLYAMIDE COMPOUND AS A
DROP-IN SOLUTION

Almost all vehicle manufacturers haveanchored the goals of the Green Dealand the development of a circular economy in their corporate strategy. In its
Ambition 2039 strategy, Mercedes-­Benz
consistently pursues the goal of balance
sheet CO2 neutrality along the entire
value chain in its new vehicle fleet from2039 on. A special attention is given to
the careful use of resources. Therefore,
the aim is to increasingly decouple
resource consumption from growth inproduction output and reduce the useof primary resources per vehicle.
The objective of the cooperation­project carried out by Mercedes-Benz,BASF, WITTE Automotive and Pyrum
to replace fossil raw materials in the­production of glass-fiber-reinforced­polyamide for use in sophisticated­vehicle components is derived fromthis strategy: resource conservation
and reduction of CO2 emissions while
maintaining the high-quality requirements, especially to safety-relevantmechanical properties as well as thepaintability of the target component.
The high-quality requirements forthe target component, a bow door
­handle of the Mercedes-Benz EQE andS-Class series production models, largely
exclude the use of recycled plastics frommechanical recycling. ChemCycling
and the chemically recycled polyamide
compound, on the contrary, achieve
the usual properties of primary plastics
and thus their suitability for the use indemanding applications. In this way, adrop-in solution became possible without retesting the material and component properties. Following an industry-­
specific recycling cycle philosophy,
ChemCycling uses tires as feedstock forpyrolysis. The mass balance approach
was advanced by simultaneously combining several sources of secondary raw
materials, FIGURE 4. This results in amore sustainable, chemically and physically identical polyamide compound forthe door handle.
In order to reduce the CO2 footprint(Product Carbon Footprint, PCF) of thepolyamide compound, biomethane wasattributed in addition to the secondary
raw material pyrolysis oil to produce
the door handle. To achieve the targeted secondary raw material quota of
more than 25 % by ChemCycling, theresulting pyrolysis oil share was 40 %.
For the remaining 60 %, biomethane
was the raw material source. The prod-31

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Sustainabilit yFIGURE 3 Origin and purifying of waste-based biomethane at BASF (© BASF)

uct defined in this way bears the product designation Ultramid B3WG6 GITBC64 bk23328, where BC64 in the­product name refers to the respective
proportion of certified Ccycled andBMB material.
In the project, substituting fossil raw
materials required for the end product bycorresponding proportions of pyrolysis
oil and biomethane was audited in cooperation with independent institutes andcertified by TÜV Nord according to theRedCert² scheme. This was the very
first audit of a product based on thisadvanced mass balance approach.
In addition to BASF as the manufacturer of the polyamide compound, theproducer of the door handle, the auto­
motive supplier WITTE Automotive, wasalso audited according to the RedCert²standard. The material transfer upondelivery as well as the material flows
and the production processes within
the company were relevant. After re­­ceiving the RedCert² certificates, theongoing production of the door handles
was able to be switched to the more­sustainable polyamide compound at
the end of 2022.
As a result of this project, BASF andMercedes-Benz sent an ­amendment tothe organization of the global International Material Data System (IMDS).
After implementing the proposed adjust-ments in May 2023, it should enable
recording of ­mass-­balanced materials,including their s­ ustainability attributes. Using the IMDS, it is possible
to meet the o­ bligations imposed on car
manu­facturers and their suppliers bynational and ­international standards,laws, and regulations.
CALCULATION OF
THE CO 2 FOOTPRINT

The greenhouse gases emitted during
the entire manufacturing process of a
product are summarized in the PCF
and expressed in CO2 equivalents perunit of a product manufactured. The

FIGURE 4 Advanced mass balance approach with combination of multiple sources of secondary raw materials (© BASF)

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PCF value of a product is calculated ina cradle-to-gate balance. For this task,
BASF has developed a software-based
solution as an online tool. FIGURE 5
shows the process steps 1 to 4 carriedout there.
Within the scope of the project de­­scribed here, several PCF calculations
were carried out assuming different
boundary conditions. Among otherthings, the PCF value for a productbased on either 100 % pyrolysis oil or
100 % biomethane was determined,
which then resulted on the other handin the 21 % PCF reduction for Ultramid
B3WG6 GIT BC64 bk23328 at theselected proportions (40/60).
Within the framework of the coop­eration project, it became clear that thecalculation methodology of the PCF is
still causing discussions among experts
in life cycle assessments. For this reason,
BASF, together with other chemical companies, is involved in the Together for
Sustainability (TfS) initiative, where it

strives to improve the sustainability of its
value chain. This initiative includes also
the creation of a uniform standard for
determining PCF values, which should
enable for the first time a fair comparisonof data from different manufacturers.
The interactive online tool, FIGURE 6, forvisualizing the concept is available on[7]. In addition, the Catena-X project isdeveloping a cross-industry standard thataims to map the PCF as a digital twin
throughout the automotive value chain.
A key success factor for this project
results from trusting the cooperationof the participating companies of­Mercedes-Benz, BASF, WITTE Auto­motive and Pyrum and the involvement of all relevant value chain stakeholders at every stage of the project.
The result of the project and the coop­erative design from idea to implementation in serial production was awarded
the Materialica Award in the category
Material with the Best of Award in­October 2022.

OUTLOOK: FROM BOW DOORHANDLES TO CRASH ABSORBERS
AND OTHER COMPONENTS

The solution approach jointly
developed for the bow door
handle is currently being transferred to a crash absorber for theMercedes-Benz S-Class. The com­ponent of the front end ensures aneven force distribution to the otherparty involved in the event of a frontalcollision. Here, too, a mass-balanced
plastic compound using pyro­lysis oiland biomethane meets the high-quality
requirements, especially regarding
crash safety. As with the bow door
­handle, the crash absorber switches
to the more sustainable polyamide­compound as a drop-in solution without additional material respectively­component qualification.
Further flexibilization of the mixing
ratio of attributed pyrolysis oil and biomethane will be even more effortless in

ELECTRIFICATIONBEYONDMEASURE.

NEXT GENERATION CHASSIS DYNAMOMETERS▪
▪
▪
▪

Suitable for current and future high power drive technologies
including hybrid, battery and fuel cell electric vehicles.
No building modifications necessary - fits into existing pits,
due to compact design.
High effiency of Synchron Motor technology (approx. 97%).
In combination with HORIBA STARS software solutions, energy
management can be optimized to recharge the vehicle automatically.

ATZ worldwide05|2023   

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Sustainabilit yFIGURE 5 Process steps 1 to 4 depicted in the project and online tool: CO2 consideration from usedtire to new door handle (© BASF | Stern GmbH)the future. BASF is currently preparing
the internal supply chain and ERP systems for a digitized attribution, which
will make it possible to adapt the sustainability attributes of a plastic productin the ongoing series production of theplastic component. This adaption will
open further options for applications of
the combined mass balance approachfor other components based on pyrolysis
oil and biomethane.
REFERENCES[1] European Parliament and Council (ed.):Directive 2000/53/EC of 18 September 2000 on
end-of life vehicles. Online: https://eur-lex.europa.

eu/resource.html?uri=cellar:02fa83cf-bf28-4afc-8f
9f-eb201bd61813.0005.02/DOC_1&format=PDF,
access: March 2, 2023
[2] UBA (ed.): Altfahrzeugverwertung undFahr­zeugverbleib. Kapitel Metallverwertung.
Online: https://www.umweltbundesamt.de/daten/
ressourcen-abfall/verwertung-entsorgung-ausgewaehlter-abfallarten/altfahrzeugverwertungfahrzeug­v erbleib#metallverwertung, access:March 2, 2023
[3] Plastics Europe (ed.): Chemical recycling.
Online: https://plasticseurope.org/sustainability/
circularity/recycling/recycling-technologies/chemical-recycling/, access: March 2, 2023
[4] OMV (ed.): OMV and Wood sign MoU forcommercial licensing of ReOil technology. Online:
https://www.omv.com/en/news/221102-omvand-wood-sign-mou-for-commercial-licensing-ofreoil-technology, access: March 2, 2023

[5] Scheuermann, A.: Strategische Partner­
schaft mit Bluealp. Shell investiert in chemischesRecycling von Kunststoffabfällen. Online:
https://www.chemietechnik.de/markt/shellinvestiert-in-chemisches-recycling-vonkunststoffabfaellen-338.html, access:March 2, 2023
[6] European Parliament and Council (ed.):Directive 2009/28/EC of 23 April 2009 on thepromotion of the use of energy from renewablesources. Online: https://eur-lex.europa.eu/legalcontent/EN/TXT/PDF/?uri=CELEX:32009L0028&from=EN, access: March 2, 2023
[7] BASF (ed.): Interactive animation –Experiencing the mass balance approach.
Online: https://plastics-rubber.basf.com/global/en/
performance_polymers/industries/pp_automotive/
transportation_sustainability/mass_balance_animation.html, access: March 2, 2023

THANKS
The team of authors would like to thank the following
contributors for their considerable contribution tothe success of the cooperation project: Michael Frik,Klaus

Ruhland,

Bernd-Uwe

Kettemann,

Jan­Heyduck, Jürgen Moczygemba, and Aline Meiser (allMercedes-Benz AG), as well as Marion Mayer,­StefanMilimonka,

ChristianKrüger,Carolin­Deregowski, Simon Rauch, Raman Chaudhari,
Eileen Orlich, Sascha Brod and Birgit Hellmann (alleBASF SE). In addition, thanks go to Georg Stalter,
Harald Hau and David Skala (all WITTE Automotive)
FIGURE 6 Interactive online tool for the visualization of the combined mass balance approach [7] (© BASF)

34

as well as Pascal Klein (Pyrum Innovations AG).
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