The K 2022 offered an immense range of innovations and application examples for – and with more – sustainable materials. Interestingly hereby was that bio-based versions were extremely popular.

Shoes made from waste gas: genetically modified bacteria produce ethanol from waste gas, which is then used to create plastic, e.g. for the Cloudprime shoes from On.

16:9

Thermoplastische Elastomere

Kunststoff Werkstoffe

Thermoplaste

Silikone

Messe K-Kunststoffmesse

kunststoffe-international.com

kunststoffe.de

Masterbatches

Additive

Polyethylen

Streifinger, Florian

Polylactid

Polyamide

Biokunststoffe

Effektpigmente

Polypropylen

Faserverbundwerkstoffe

Andere Werkstoffe

Kunststoff-Rezyklat

Silikonkautschuk

Kautschuk / Elastomere

Is Bio the New Standard?

Automakers have formulated ambitious plans for their vehicles. We discussed this topic with Frank Schumann from Trinseo.

Batterien

Energiespeicherung

Elektromobilität

Mobilität

Lichttechnik

Kunststoff-Recycling

Kunststoffverarbeitung: Verfahren

Kunststoff-Aufbereitung

“Nothing Speaks against the Use of Recyclates for Demanding Components”

The quality of recyclates can be improved very well by means of suitable additives. An overview of the variety of products and their suppliers.

Overview: Additives for Plastic Recyclates

Stabilisatoren

Vitamins for the Circular Economy

The quality of recyclates is seen as too low. Improvements are possible by using additives, as was shown by the exchanges during the Forum Plastic Recyclates.

Quite clearly, the central theme of this year’s conference  was additives for recycling materials.

Recycling

Umweltmanagement

Kreislaufwirtschaft

Additives Are Decisive

In general, recycled chocolate molds of PC do not meet the food contact requirements. A new recycling strategy is to provide a remedy.

Polycarbonate is frequently used for molds in chocolate production.

Polycarbonat

The Chocolate Side of Polycarbonate

The stabilization of used plastics is costly. Online measurement during compounding allows for stabilization directly in production.

Plastic waste often has a very different stabilizer content. This must be precisely determined in the recycling process. 

Determined Online, Recyclate Wins

Automakers want to reduce the carbon footprint of their vehicles. Frank Tönniges from Adient explains what savings are possible in seating.

Frank Tönniges: “Polyurethane has no competition. No material can currently hold a candle to it.”

Polyurethan-Schaumstoffe (PUR)

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Polyurethan

“We Are Saving 50 Percent  on Foam Emissions”

Kraiburg TPE’s latest thermoplastic elastomer (TPE) has been specially developed for consumer and industry applications and contains up to 40 % post-consumer recyclate (PCR). In accordance with standard ISO 14021, the manufacturer recycles materials that end consumers from households and the industry can no longer use for their intended purpose.

The latest solution from Kraiburg TPE makes a post-consumer recycling proportion of 40 % possible. The TPE is partly made from household waste. 

Compound

TPE with a Post-Consumer Recycling Proportion of 40 Percent

Plastic recycling: Kreyenborg uses infrared technology for the reduction of unpleasant odors in plastics.

Everything fresh: the two-stage IR-Fresh process removes unpleasant odors from recyclates.

Infrarotstrahler

Kunststoffverarbeitung: Maschinen und Komponenten

Materialhandling

IR-Fresh Minimizes Odors in PCR Granulates

Material and manufacturing process optimized, CO2 saved: recycled wash cap from Pöppelmann K-Tech closes the loop.

Material and manufacturing process optimized, closed loop: Recycled wash cap for the automotive industry. 

Spritzgießen

Schaumspritzgießen

Sustainable Wash Cap

Christian Schiller’s goal is to turn the phrase “plastic waste is recyclable material” into reality. His tool of choice: digitalization.

Digitale Transformation

Wirtschaft

Innovationen und neue Technologie

Start up

Unternehmen und Unternehmer

Ehrhardt, Melanie

“We See Our Work as Basic  Digitalization“

RCS Plastics processes PET flakes into high-quality regranulate for preform and beverage bottle manufacturers. To ensure the required food quality of the recycled material, the company relies on Sikora technology for the quality control of the rPET flakes and pellets.

Cedric Steeg, Employee in Quality Assurance, holds material sample in front of the Puritiy Concept V.

Qualitätssicherung

Polyethylenterephthalat

Check Food Quality of Recyclates

Solvay and Hegen Partner to Bring the First Baby Bottle Made with Recycled Content to the Market.

In the future, Hegen will manufacture baby bottles from mass-balanced PPSU recyclate.

Messe Fakuma

Recyclates Now Also for Baby Bottles

Using the latest technological advances in flake sorting helps bridge the gap between supply and demand.

Mixed plastic waste: With about 180.5 million t polyolefins make up the lion‘s share of annual plastics production.

Quantum Leap in Recyclates Quality

Dupont is adding new, more sustainable grades to the Hytrel TPC-ET product family. Hytrel Eco B is based proportionately on renewable raw materials.

Kunststoffe, biobasiert

TPC with up to 72 Percent Biomass Content

Recyclate Reduce the CO2 Footprint in Seals and Interior Applications

The use of TPE materials with recycled content supports the constantly evolving material requirements of the automotive industry regarding the use of recycled materials and CO2 footprint. In addition to classic exterior applications, TPEs are increasingly used in demanding interior applications with high odor and emission requirements.

The use of TPE materials with recycled content increases the sustainability of vehicles. They are also used more and more in the interior.

In recent years, the focus of industry and consumers on the environmental impact of materials has steadily increased. This is particularly evident in the automotive industry, with many OEMs setting ambitious targets for recyclate use. Volvo, for example, aims to use at least 25 % recyclate in every new car by 2025 [1]. Renault already achieves 33 % recyclate use in cars produced in Europe [2]. A similar recyclate quota is also targeted by BMW and Mercedes, and by 2030 the share of secondary raw materials in all models should increase to 40 % on average [3, 4].

However, a higher recyclate quota places many new challenges on the materials, as more complex components must be realized. Good examples of this are interior visible parts and seals, which until recently could not be produced with recyclate. With new thermoplastic elastomers (TPE), however, even these demanding applications can be realized, the recyclate quota increased and the CO2 footprint reduced.

In general, there are currently two types of recyclate on the market: pre-consumer/post-industrial recyclate (PIR) and post-consumer recyclate (PCR). The distinction is usually made according to the ISO 14021 standard, which defines the categories: Post-industrial recyclate is material diverted from the waste stream during a manufacturing process. Excluded is the reutilization of materials such as rework, regrind or scrap generated in a process and capable of being reclaimed within the same process that generated it. Injection molding sprues or extrusion edge trimmings can become PIR, preferably from high-value products such as food, hygiene and medical applications.

In contrast, post-consumer recyclate is obtained from the waste of end consumers. PCR sources from end-of-life vehicle recycling are conceivable. It can be seen from these definitions that post-industrial recyclate is generally easier to obtain in purer qualities and bright colors (Fig. 1), while post-consumer recyclate is usually of lower quality.

Selection of the Correct Type  of Recyclate

Waste, for example, from industrial or household collections, is mechanically shredded, separated and then processed into a regrind or regranulate. These are used as raw materials for TPE compounds, which are then processed into the final component by injection molding or extrusion. Due to the varying quality of the waste products, it is very important to select the correct type of recyclate depending on the market segment and origin.

In addition to such mechanical recyclate, intensive work is also being done to generate recyclate by chemical means (for example, pyrolysis or depolymerization). However, this is still in the experimental phase, and commercial quantities are limited.

The automotive sector has historically been one of the most important segments for recyclate, although the technical requirements for the materials are usually high.

For example, sufficient material will need to be produced over the model’s life, i.e., the recyclate source must be sufficiently large and reliable. For a material to be specified for a component, the material quality must remain constant over the complete runtime. Each component must be evaluated to determine whether recyclate content is a possibility. Despite these requirements, the automotive industry has set high targets for the use of recyclate. The most obvious case for the use of recycled materials is exterior applications where temperature, UV stability and visibility are required. Examples are wheel arch liners, kick plates, side steps and mud flaps. Depending on the hardness of the application, high recycled content (> 50 %) is possible, and post-consumer recyclate can be used. PCR materials usually have a stronger odor, but this is less relevant in such applications. However, to achieve high levels of recycled content in the car, only working with components with Shore D hardness and low requirements will not be sufficient. This is why softer applications are increasingly being switched to TPE with recycled content.

Such applications include various components for air and water separation and disc seals, usually designed in the hardness range of 60 to 90 Shore A. In addition to the lower hardness, such materials must offer sufficient recovery behavior and sealing to fulfil their function (low compression set). Furthermore, such components often have long flow paths and relatively complex geometries, which is why highly flowable materials are necessary. Stable extrudable materials with a low compression set below 40 % (70 °C/22 h) are required for profile seals.

TPEs with recycled content can also be used for applications in the engine compartment, but the media with which they come into contact and the temperatures to which they are exposed must be considered. For such high requirements, switching to vulcanized TPE (TPV) may be necessary, in which recycled material can also be used, but the percentage is more limited.

However, a more challenging field of application for TPEs with recycled content is the automotive interior, as many requirements can be problematic for mechanical recyclate.

TPE with Recycled Content for  the Interior

In the interior, it is imperative that the materials used do not smell. This is especially important because odors are amplified many times over by the limited space in the car and increased temperatures due to sunlight. For this reason, odor tests in the automotive sector are carried out at elevated temperatures (for example, 80  °C).

In addition to these requirements, TPEs for the interior must be easy to process to produce visually flawless surfaces. Typical applications include mats, HVAC components (heating, ventilation and air conditioning) and soft elements for noise and vibration reduction (e.g., in the center console) (Fig. 2). Other OEM requirements, such as emission limits, mechanical performance, heat resistance and light fastness, must, of course, also be met by materials with recycled content. The fulfilment of these requirements and the regulatory harmlessness (e.g., compliance with GADSL and Reach specifications) must be guaranteed for recycled materials in the long term.

As mentioned above, odor and emissions, in particular, have been problematic, so only now can the first TPEs with recycled content be used for interior applications. The Table shows the emission values of some typical Dryflex Circular TPEs with PIR recycled content for the interior. The emission values are well below the limits commonly used by OEMs. Depending on the hardness and the requirements of the component, recycled content of approx. 20 to 50 % can be achieved in the interior.

By using recycled materials, it is also possible to reduce the CO2 footprint of TPE compounds. The amount of reduction depends on the raw materials used and how they are recycled. Furthermore, the calculation methodology and system boundaries play an important role. For intermediate products, the cradle-to-gate approach according to ISO 14040, ISO 14044 and ISO 14067 is often used.

The main factors influencing the CO2 footprint of a TPE compound are the raw materials used, the transport of the raw materials, the compounding process, and the packaging materials. The largest contribution is made by the raw materials used (>85 %), which results from the high (often still fossil) energy input for the synthesis of the monomers and their polymerization. In comparison, the energy input and the associated CO2 emissions for processing recycled materials are usually lower.

According to this calculation, the global warming potential of an 85 Shore A material can be reduced by 23 % if a material with 30 % post-industrial recyclate is used instead. A similar result is obtained using 40 % post-consumer recyclate in a 40 Shore D TPE: the global warming potential is reduced by 26 % (Fig. 3).

In addition to materials with recycled content, it is also possible to use TPEs with bio-based content for applications in the automotive sector. For example, polymers, plasticizers or fillers based on plants, sugar cane or fiber can serve as raw materials. For example, a bio-based floor mat has been realized (Fig. 4) that fulfils the usual requirements for automotive interiors (e.g., light resistance and low VOC and odor emission values). It is also possible to use biofillers like natural cork to introduce advantages such as low density, eco-design aspects and a low CO2 footprint.

In summary, with the right choice of raw materials, it is possible to realize automotive applications in the Shore A and D hardness range with recycled content. Depending on the application, recycled content of up to 50 % can be realized, which supports suppliers and OEMs in achieving their sustainability goals. With new, softer recyclate, it will be possible in the future to further increase the recycling share without having to compromise on material performance.

Close cooperation between OEMs, suppliers, compound manufacturers, recyclers and (bio)raw material producers can accelerate the shift to more sustainable materials in vehicle construction. In addition to working with various OEMs, Hexpol TPE is also a partner in the Polestar 0 project to develop a climate-neutral car [5]. Cooperation with almaak international GmbH (manufacturer of recycled technical thermoplastics) enables the combination of TPE and technical thermoplastics with recycled content for 2-component injection molding [6].

[1] <a href="https://www.media.volvocars.com/ch/de-ch/media/pressreleases/230703/ab-2025-stecken-in-jedem-neuen-fahrzeug-von-volvo-cars-25-prozent-recyclingkunststoffe" target="_blank">https://www.media.volvocars.com/ch/de-ch/media/pressreleases/230703/ab-2025-stecken-in-jedem-neuen-fahrzeug-von-volvo-cars-25-prozent-recyclingkunststoffe</a>

[2] <a href="https://www.renaultgroup.com/en/news-on-air/news/circular-economy-moving-up-a-gear/" target="_blank">https://www.renaultgroup.com/en/news-on-air/news/circular-economy-moving-up-a-gear/</a>

[3] <a href="https://group.mercedes-benz.com/nachhaltigkeit/ressourcen/kreislaufwirtschaft.html" target="_blank">https://group.mercedes-benz.com/nachhaltigkeit/ressourcen/kreislaufwirtschaft.html</a>

[4] <a href="https://www.press.bmwgroup.com/deutschland/article/detail/T0403367DE/bmw-group-nachhaltigkeit-durch-innovation-2022" target="_blank">https://www.press.bmwgroup.com/deutschland/article/detail/T0403367DE/bmw-group-nachhaltigkeit-durch-innovation-2022</a>

[5] <a href="https://media.polestar.com/de/de/media/pressreleases/659180" target="_blank">https://media.polestar.com/de/de/media/pressreleases/659180</a>

[6] <a href="https://almaak.de" target="_blank">https://almaak.de</a>/

HEXPOL TPE GmbH  

https://www.hexpoltpe.com

Ausgabenartikel

The selection of high-quality recyclate enables their use in demanding automotive applications.  

Fig. 1. Example of a typical recycling process from PIR and PCR sources. Generally, the quality of PIR are higher, and they are easier to reuse for plastic products.

Fig. 2. The use of recycled material in air control elements requires a very high quality of recycled material.

Fig. 3. Reduction of the global warming potential (GWP) through the use of recyclate (calculated in kg CO2e/kg material): Significant savings are possible with both PIR and PCR materials. 

Fig. 4. Bio-based TPEs can also be used to great effect in interior applications, such as inlay mats. 

Table. Typical odor and emission values of Dryflex Circular TPE with recycled content. 

KUint2-23_Hexpol TPE - Hauptartikel

TPE with Recycled Content for Interieur Parts

Florian Dresel, M. Sc., is Central Research Engineer at Hexpol TPE.

Dr.-Ing. Thomas Köppl is Group Product Manager Hexpol TPE; <a href="mailto:thomas.koeppl@hexpoltpe.com">thomas.koeppl@hexpoltpe.com</a>

Dipl.-Chem. Michael Walter is Business Development Manager at Hexpol TPE.

Hexpol TPE is a global polymer compounding group specializing in thermoplastic elastomers (TPEs). TPEs are used in key industries such as consumer, medical, packaging, automotive, construction and electronics. The German site is located in Lichtenfels, Upper Franconia, Germany.

Read the German version of the article in our magazine Kunststoffe or at <a href="https://www.kunststoffe.de/a/fachartikel/weich-elastisch-und-recycelt-3455681" target="_blank">www.kunststoffe.de</a>