FAQ and glossary

These terms are part of the vocabulary of the sustainable circular economy, the methods and parameters used and are used repeatedly on our website. For this reason, we explain some of the most important and most frequently used terms here. We also answer the most common questions about sustainable circular economy.

Sustainable circular economy

The circular economy is a regenerative economic system that requires a paradigm shift to replace the concept of "end of life" with reduction (Reduce), alternative reuse (Reuse), recycling and recovery of materials (Recover) throughout the supply chain. It aims to promote value conservation and three-dimensional sustainable development. This is made possible by an alliance of stakeholders (industry, consumers, policy makers, academia) and their technological innovations and competencies.


A product or packaging is recyclable if its components can be returned to their original state using industrially available processes and a collection and recycling system exists for them. Recycling can replace virgin material on an equivalent market.

Chemical recycling

Chemical recycling involves returning substances to their original form. For example, the monomers used in production can be recovered from plastics. There are numerous processes that are counted as chemical recycling. What they have in common is that chemical bonds are dissolved. Enzymes, solvents, temperature and other methods can be used. These processes are usually energy-intensive, but conserve resources.

Material flow analysis MFA

Material flow analysis shows flows and stocks of different materials or products within a defined system (e.g. company, country, world). The systematic recording of material flows and storage simplifies the overview and enables the understanding of complex systems, such as waste systems. Knowledge of the transformation, transport and storage of valuable and hazardous materials gained through MFA forms the basis for identifying both resource potentials and risks to human health and the environment.

Life Cycle Assessment (LCA)

A life cycle assessment (LCA) is a compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle*. Therefore, LCA is one of the most important tools to describe and improve the sustainability of a product.  

An LCA consists of four steps. In the first step, the target and system boundaries are defined. In the second step, all inputs and outputs of the investigated product system are collected. Then, in the third step, environmental impacts are offset against the inputs and outputs to calculate the environmental impacts of the product system. In this step, it can be selected which so-called impact category (e.g. impact on climate change, impact on ozone layer depletion, impact on human or ecotoxicity, etc.) should be considered. In the fourth step, the results are interpreted and put into context.

*Definition according to International Organization for Standardization (ISO), The New International Standards for Life Cycle Assessment: ISO 14040 and ISO 14044 (ISO, Geneva, Switzerland, 2006).

Mechanical recycling of plastics

In mechanical recycling, plastic waste is turned into secondary raw material. In this process, the plastic products are first mechanically shredded, often washed to remove food residues, for example, and then melted. When melted in an extruder, plastic pellets can then be produced again. One challenge in the mechanical recycling of plastics is that the melting down of different polymers can have a strong negative impact on their properties. For example, a proportion of PE in PP recycling can impair the properties of the PP recyclate to such an extent that the recyclate can no longer be used afterwards. An important step for a successful mechanical recycling of plastics is therefore a clean, preceding sorting according to polymer types.

Design for Recycling, D4R

Design 4 Recycling, D4R, is a term for rethinking products. In the design process, attention is paid not only to the function of a product or packaging, but also to its recyclability. D4R is thus one of the most important steps on the way to a circular economy.

There are various guidelines for plastic packaging and other products that indicate when a product is recyclable.


Bioplastics come in different forms. On the one hand, there are biobased plastics, where the raw material from which the plastic is made is renewable. On the other hand, there are biodegradable plastics. Here, either additives are added to the plastic that accelerate the rate of degradation, or the plastic itself consists of compounds that degrade more easily than conventional plastic. The following graphic provides an overview of the possible combinations with examples of which plastics belong in which category.


Sustainability originally meant that something does not exceed the natural regenerative capacity of a system. Today, the term encompasses the 3-pillar model of sustainable development. Sustainable development means meeting the needs of the present in a way that does not limit the opportunities of future generations. It is important to consider all three dimensions of sustainability - economically efficient, socially just, ecologically viable - on an equal footing.

Digital Product Passport, DPP

The digital product passport (DPP) is intended to increase the transparency of products. It typically consists of a data carrier (QR code, RFID chip, NFC chip) and a database. With the help of the DPP, consumers will receive information on materials, maintenance and recycling paths at the end of a product's life. On the other hand, the DPP should make it possible to recycle products, as the composition can be read out at the recycler with little effort.

Is the circular economy always sustainable?

Circular economy is one of the most important concepts that can contribute to sustainability. However, an assessment of the impact on sustainability is extremely important, because it may come as a surprise, but circular economy is not sustainable per se. For example, pollutants can accumulate in material cycles (recall the case of elevated heavy metal concentrations in children's toys). Or a new refrigerator makes more sense than repairing the old appliance because of increased energy efficiency. Or reusable alternatives, which are used only 3 times instead of 50.

What are the differences between material, theoretical and actual recyclability?
  • Material recyclability of the packaging components: A process exists by which the used material can be returned to its original state (e.g. melting process).
  • Theoretical recyclability of a product: In addition to material recyclability, theoretical recyclability defines that a product consists of a mix of materials (incl. labels, lids, etc.) that can be recycled. If the product is a composite product (e.g. composite packaging such as multilayer plastic packaging), it must be possible to break down the product into its materials, whereby material recyclability applies to all partial materials.
  • Actual recyclability of a product: In addition to theoretical recyclability, a collection and recovery system must be available in which the materials can be processed into high-quality secondary raw materials within a geographically reasonable radius. The secondary raw material must make up >70% of the input material, be of high quality (free of pollutants and with the same physical properties as the primary material as far as possible) and enable local recycling.
Are bioplastics more sustainable than conventional plastics?

Bioplastics (internal link to glossary), whether biodegradable or biobased, are not per se more sustainable than conventional plastics. On the contrary, new problems may arise in composting or recycling. Nevertheless, bioplastics can have advantages over fossil-based plastics in certain situations.


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