What does a mattress have to do with a PET tray?


6 insights about Design for Recycling within the plastics sector

During the Circular Plastics Conference 2022, attention was paid to all interdependent areas in the plastics value chain. From sorting and washing to recycling and production. For each of these topics, the challenges, opportunities and new technological developments were discussed. CIRCO's Ingeborg Gort attended the session on Design for Recycling and gave a presentation on the CIRCO methodology and experiences in the plastics sector. Read further to learn about her main takeaways from this session!

220901 matras pet tray

Design for Recycling

Products and packaging are often not (properly) recyclable. To increase recycling rates, it is important to take future recycling into account during the design process. This is called ‘Design for Recycling’. This requires designers to integrate all requirements together with all stakeholders in the process (collectors, sorters, recyclers and producers).
But how do you organize that? During a session at the Circular Plastics Conference that took place in The Netherlands, Auping, Hordijk and Filigrade, led by moderator Roland ten Klooster (University of Twente and Plato product consultants), presented how Design for Recycling underpins their products and activities. Geert Doorlag (principal researcher at Auping) explained the details of the circular Evolve mattress, made entirely of 2 easily recyclable and easily separable materials (plastic and steel). Rik Hennink (CEO Hordijk) discussed various innovations for sorting PET trays and reusing the recyclate in trays. Han Meiberg (CTO Filigrade) explained how coding can help to sort packaging into food and non-food packaging.
Inspirational stories. Which, in my opinion, can be summarized in six overarching insights for the entire plastics sector.


1: Mono (material) makes it easy

Both a mattress and a PET tray consist of layers with various functionalities. Such as sealability, gas barrier for trays and comfort and ventilation for mattresses. All kinds of product and material innovations made the PET tray thinner and lighter in weight and strangely enough the mattress thicker and heavier. It also ensured that the products consisted of different materials that were glued together.

The main innovation from Auping and Hordijk concerns the development towards one type of plastic, without compromising the user requirements. By using monomaterial, both companies were able to take major steps towards a circular product.

In addition to a monoplastic, Auping mattresses also consist of pocket springs. In practice, these are already easy to separate from each other in today’s mattress recycling plants. In the Netherlands, mattresses are recycled by Retour Matras and Matras Recycling Europe.

Auping Evolve

Auping Evolve mattress

2. Do not burden others with your (poorly recyclable) materials

Cascading – the recycling of materials for other products – is not completely circular. It is better to close your own cycle. Apply the materials from your own product group, range or sector.

For example, mattresses are often recycled into judo mats or cow mats. That is a linear product and comes down to a delay in combustion. So not very circular.

In the past, Hordijk used soft drink bottle material for trays. Not very circular either, because on the one hand it means that new material (primary fossil PET) is needed for bottles. On the other hand, the trays were eventually burned. Moreover, the bottle flow is now no longer available, because they are used for bottles. So your input stream can dry up just like that.

The conclusion? A mattress must become a mattress again, a tray must become a tray again.

Side note is of course that it is better than burning. So as long as there is no alternative, cascading is a suitable alternative in specific applications.


3. Some plastics (or materials) are more circular than others

The properties of different plastics make them more or less suitable when you design with recycling in mind.

For example, PET (polyester) seems to be the most suitable plastic at the moment. It is thermoplastic and therefore easily recyclable mechanically. In addition, it has a dense structure and does not absorb chemical agents (such as benzene). It is also suitable for post-condensation; an extra step that ensures that the properties of the material can be upgraded during the recycling process (this is not possible with polyolefins such as PP and PE). Finally, an additional advantage for mattresses is that polyester has a fire retardant effect.

Although PET is currently preferred, the search for better materials continues. Both Auping and Hordijk are constantly looking for the best suitable materials.


4. Tariff differentiation works as an incentive for Design for Recycling

For PET bottles there is a deposit system that is mandatory for all players in The Netherlands. This is not (yet) available for many other food packagings. In that case it is important that there are incentives for the parties that market the packaging. This encourages them to ensure that the packaging is easily recyclable. A price incentive is obvious here.

A system of rate differentiation was introduced fairly recently for short-cycle plastic packaging, in The Netherlands. Companies that market packaged products pay a levy to the Dutch Waste Fund on the packaging. To further encourage the use of easily recyclable packaging, The Dutch Waste Fund for Packaging (Stichting Afvalfonds Verpakkingen) is increasing the levy for poorly recyclable packaging and lowering the levy for readily recyclable packaging. Although there is still a lot to learn, this system already seems to be working.

The most important thing that a long-cycle product such as the mattress can learn from this is first of all to use materials that are recyclable and can be used for the same application. But also to arrange a tariff differentiation for this within the voluntary producer responsibility (UPV).

Hordijk rPET tray

Hordijk rPET tray

5. It is of mutual interest to set a standard in the market

To really make an impact with recycling, you have to work together with your competitor. This is the only way we can move towards new market standards that ensure that recycling is profitable. That is in everyone’s interest.

The Auping mattress range has been 80% (!) circular since May 2022. A gigantic achievement, since they only sold the first circular mattresses three years ago. Auping also produces these circular mattresses for other mattress brands. They have made agreements about this: competitors may make and sell the same basic mattress, but not the more luxurious types. Auping sees that consumers are very enthusiastic about the circular mattresses, which helps enormously in enthusing other manufacturers.

Filigrade takes the same approach. They test their CurvCode coding with a consortium of more than 40 parties. This coding makes it possible to distinguish and sort out non-food from food packaging in plastic sorting installations. This gives you proof that the material was originally food grade (this is necessary due to legislation and must be requested from the European Food Safety Authority). A wonderful solution, but something like this will only become profitable if a large part of the market applies it.


6. Mechanical rather than chemical recycling

Depending on the type of polymer and type of technology, chemical recycling is often much more energy intensive and therefore entails a higher environmental impact for the processing of materials than mechanical recycling. So only apply chemical recycling if it has a lower impact and produces a better yield or if mechanical recycling no longer produces good quality.

There is one exception: food grade plastics. At the moment it is not yet possible to obtain a food grade with mechanical recycling in a non-closed system (such as a deposit). Fortunately, this is being worked on, because recognisability in sorting (CurvCode) will soon allow sorting on food and non-food streams, which means that food-grade material can also be sourced in an open system.

The trade-off that manufacturers make between mechanical and chemical recycling is subject to tension.

For example, Hordijk currently uses an A B A construction in the PET Tray: the inner layer is recycled, the outer layers are made of virgin material. The virgin layer can also be replaced by chemically recycled PET in the future. After mechanical recycling of PET several times, you get a gray or yellowish discoloration that is undesirable according to the producer, at which point chemical recycling will still take place (in the future).

The mattress sector is also still facing challenges in this area. PU foam (Polyurethane foam in mattresses) does not yet appear to be a future-proof material, because it is not highly mechanically recyclable. However, the possible chemical recycling routes  (including hydrolysis) have so far yielded a low yield; you don’t get all the raw materials you put into it, just the polyol. So that means that you still need new fossil raw materials (including isocyanates) to be able to make foam again. This while raw material suppliers for PU foam manufacturers do focus on chemical recycling of mattresses to make polyol for mattresses. The question is: will this be enough?


Get started with Design for Recycling

Concluding, there are already a lot of starting points to begin with Design for Recycling. But it remains an area in development, in which a lot of materials research is going on.

Do you want to get started with circular design and collaboration in the chain? Then follow a CIRCO Track!