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Challenges in developing materials for the automotive sector: Volkswagen is reusing coffee waste

Silverskin: Volkswagen is developing, among a series of bio-based materials, a leatherette with coffee waste as a principal component of the filling 

Ecological development in the automotive sector

The climatic aspects and problems related to mobility have made the issue of the use of electric cars and their evolution relevant, causing the research departments of individual car manufacturers to focus on this area. On a consumer-level, the focus is on the ecological aspect which is another key point from which automotive research develops, confirms Oliver Schauerte, Head of Group Research Materials and Production Processes at Volkswagen. The attention is often focused not only on having a low impact and low carbon footprint, but also in the process of conceiving and creating the vehicle. 

In order to continue working in this direction, it is inevitable to rethink the role of interiors, such as animal leather. From this, much research has undergone based precisely on the constitution of internal material. Martina Gottschling, researcher for Volkswagen Group Innovation, states: «We are working on several materials, but many of these are not completely developed right now. That is why we tried to focus on some materials in order to have ready for use material that results in more ecological development than the previous one». The goal is to reach almost zero in terms of energy consumption and in the carbon footprint of the machine itself.

Leatherette and organic components

Different research has been carried out to create a leatherette that can be used for interiors. However, leatherette has some negative elements to it. For one, it involves the use of plastic materials for its composition, in particular the filling. In fact, this type of leather is composed of a fabric back, the foam with filling materials and then the outer surface, Volkswagen reveals.

What the company is trying to implement is the organic components that constitute the leatherette, trying to direct themselves towards a more ecological car. «Faux leather is a petrochemical material. By substituting some of the raw materials, the percentage of petroleum can be reduced and of course also the carbon footprint can decrease», continues Gottschling. «In case organic substitutes are going to be used, it is also possible to use renewable materials».

Volkswagen selection of Heimbs’ Braunschweig-based coffee roaster

In order to increase this percentage organically, different materials and sources which are already existing, such as from waste, have been studied and evaluated to be used as filler materials. They explain that the research focused on local and nearby businesses that could feasibly supply the waste stream, such as industries or manufacturing companies.

Among the properties researched for viable waste streams, are the amount and the availability, but also the specific properties of the material considered, and the additional treatments used by the industry. After careful consideration, Volkswagen selected the Braunschweig-based coffee roaster Heimbs, founded in 1880 and active since 1954 with production in the northern district of Ringgebiet, forty kilometers from the Wolfsburg Autostadt.

The raw material: coffee

Gottschling explains that coffee, as a waste material, is obtained from its processing. «The high-quality green coffee is stored in jute sacks and stored in the basement of the factory; it is kept in a thick-walled vault, which fortunately remained intact during the war. Inside there is an herbaceous, slightly acidic smell, quite different from the one we all know, which is the result of the roasting process», says Volkswagen’s MoDo website about the chosen roaster. The roasting process is the step that supplies the waste as a usable product. As the coffee beans are roasted, the silverskin, a kind of film that covers it, is accumulated as a waste material or by-product. 

This does not have many uses. The majority gets burned whilst a small part is used as a fertilizer; it cannot be used for animal feed or as a biogas because it contains residues of caffeine even after the process. Through the roasting process the material is easily selected by the manufacturer. In this way it is made ready to be used in the creation of the leatherette and is economical as it would have no other use. Another positive aspect of this material is the possibility of receiving it already dried, without having to do it in a later step within the Volkswagen company and thus saving energy. 

Additionally, Gottschling points out that it takes on an optimal shape for processing. Schauerte explains that the choice of the material was also due to a certain homogeneity of the product for interior use if compared to other popular organic leather filling, confirming that this is the first and perhaps fastest step in replacing the previous materials used with bio-based materials.

The aim was to (achieve a bio-based content of more than 50% in the leatherette) use this type of material for fifty percent of the product. In order to use the by-product of the coffee, the producer is only required to receive it from the roasting company, which is not a problem considering that a medium-sized roasting company already accumulates several bags of this film per day, they explain.

Lampoon, Braunschweig-based coffee roaster Heimbs
Volkswagen selected the Braunschweig-based coffee roaster Heimbs

Silverskin in the car production process

The material is then involved in the usual process for the production of faux leather and used, with additional materials, to fill in the coverings of the vehicles. To produce faux leather, Volkswagen relies on an external company that is at the forefront of the issue relevant to car interiors.

«The goal in the production of the material was to reach a share of renewable materials to more than fifty percent, so the filler made with silverskin was not enough; also, the textile back and softening agent has biological material and overall, we reached up to fifty-one percent biological material and working to do more», explains Gottschling. 

In addition to the biomaterial attribute, other performances were also evaluated as convincing, the same ones that are inspected in all types of interior materials used. In the car industry,  materials have to fulfill all the requirements. For example, materials chosen need to successfully perform forty tests to evaluate the aging effects which take part over a lifetime.

There are also mechanical stress tests in addition to color degradation, wet and dry situations, climate swing, and other aging aspects. «At the moment, we are still in the development process and the material fulfills most of the criteria, but in the end, it will fulfill all the criteria and it will be at least as good as other faux leathers», says Gottschling. 

Durability is a central issue when it comes to a leather material, especially in the automotive sector; it is difficult to compare it to animal leather since they are completely different. Authentic animal leather is durable but it needs care in order to last the time of the vehicle, while faux leather does not need regular care and can still be maintained for the whole lifetime of the vehicle.

The added value of leatherette is that some waste material can be saved in the production because it arrives in a geometrical shape. Animal leather, on the other hand, has a natural shape that needs a lot of cutting to create a seat, for example.

Lampoon reporting: the use of coffee by-product

The process is interesting because it looks at an aspect of the whole lifecycle and avoids considering durable materials that would not have a positive impact. Some people think of leather as a waste material from the food industry.

Gottschling points out that actually, even its production process contributes to a negative impact on the environment, such as during the tanning process. Regarding numbers when it comes to carbon emissions and global warming potential, traditional leather produces about fifty-four kilograms per square meter for a seat cover, depending on where the cows come from. 

If considering that the cows are sourced locally for the process and an improved ecological tanning process is used, it is still twenty-nine kilograms; while for leatherette created by coffee in comparison, is under four kilograms. Calculating precisely the amount of energy and emissions spent in the production of faux leather is complicated due to the involvement of different suppliers.

«We have to admit that it is really difficult to assess the carbon footprint of natural leather. Plus, you have to take into account aspects regarding allocations: what share of footprint is for the meat which one is for leather products. We oriented ourselves on guidelines of European commission and I think the numbers are valuable, others can have totally different points of view about it», confirms Schauerte. 

The use of coffee by-products opens up new frontiers of uses in terms of natural and renewable materials. Of course, in some business areas, such as the automotive industry, it can become difficult to evolve in the direction of a total biodegradable production. The researchers confirm that the rest of the material used is still of petrochemical derivation, but the development toward innovative sources should represent only the first step.

Further approaches in which the company is working on are, for example, on the basis of cellulose, and these materials could reach 100% biodegradability. «We have a strategy to come to have fully biodegradable covers, for  all interior surfaces, but it takes some time. The first steps we are doing are biomaterials development like the coffee leatherette one, and others we are working on and in the long term we are trying to develop fully biobased materials which are 100% biodegradable», states Schauerte.

Volkswagen 

The company has operated since 1937 in the automotive industry. It is developing through Volkswagen Group Innovation, a more sustainable mobility including a series of research on innovative production materials.

The writer does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article.

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Hemp / made in Italy
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check and buy on Prototipo Store
item collections in limited edition
crafted according to our editorial search

Hemp / made in Italy
Lampoon is working to restore
Hemp production in Italy
as hemp is the one and only
natural vegetal fiber sourceable in the country
for more info, please email us at [email protected]

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