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Design for Recycling

How can plastic packaging be made suitable for circular economy?

White packaging made of mono-material with correspondingly small labelling is highly recyclable, as it is recognised as PE or PP in the sorting process.
White packaging made of mono-material with correspondingly small labelling is highly recyclable, as it is recognised as PE or PP in the sorting process.

(Bild: Buch&Bee – stock.adobe.com)

However, recycling-friendly packaging is not a dream of the future; it already exists today, the easily recyclable packaging made of plastic. Brand manufacturers have partially converted their packaging, packaging material manufacturers are developing packaging made of mono-material and machine manufacturers are ensuring, among other things, with retrofit kits that these materials can be processed without problems.

There are clear guidelines from the "Central Packaging Register Office". This is a foundation under public law from Osnabrück. It developed a design catalogue to separate recyclable packaging types from ecologically unusable ones. The so-called minimum standard specifies criteria that must at least be taken into account when determining recyclability:

For example, a sorting and recovery infrastructure for mechanical recycling must be available for this packaging. Furthermore, the packaging must be sortable and, if necessary, separable into its components (if separation is required for high-quality mechanical recycling).

"For example, a plastic cup with a paper band causes problems," explains Christina Schulz, Design for Recycling (D4R) expert at Grüner Punkt. "The consumer should separate, but we see in the sorting plants that the consumer just doesn't do that. Even if there is a perforation on the packaging, the consumer does not separate. A cup with a paper band is sorted as paper. The sorting machines detect the material on the surface, recognise it as paper, then the cup is sorted incorrectly and ends up in the paper mill, so the plastic cup is lost."

Other obstacles to successful plastic recycling include large-area labelling with foreign material, full-sleeve labelling, multilayer construction (except PE/PP-EVOH), metallisation (except metallised on the inside/in the middle layer), dark colour design using carbon black-based pigments (also when used in inner layers), different types of plastic on the front and back sides, and metal pigments applied on a large area (lacquering, coating or embossing).

"The minimum standard clearly states that these are incompatibilities for recycling and thus already provides an initial orientation for a packaging designer," explains Christina Schulz.

To support their customers, dual systems for waste disposal, such as Belland Vision, Interseroh, Reclay Group or Duales System Deutschland, have developed IT tools with which their customers can check whether their packaging is recyclable and meets the minimum standard of the Central Packaging Register.

Design for Recycling is the solution approach from Grüner Punkt, which aims to ensure success in recycling through sustainable packaging design. The IT tool called Recycling Compass was developed to enable users to easily rate the recyclability of their packaging. The tool's assessment is based on the methodology of the Cyclos-HTP (CHI) Institute for Recyclability and Product Stewardship. The online tool is constantly updated and adapted to the current minimum standard of the Central Packaging Register.

Not only branded companies and distributors of packaging use these IT tools. Packaging manufacturers and machine builders are also usually involved in the development process towards recycling-friendly packaging. There are a few pitfalls to overcome in this process. "The still missing or unclearly formulated legal requirements lead to unclear interpretation for recycling companies, also with regard to the technology used and the procedure in the separation and sorting process. As a result, one and the same packaging is often assessed completely differently, which sometimes complicates our process when developing new solutions," explains Stefan Dangel, Head of Marketing and Sales at Sealpac.

Max Wolfmaier, Sustainability Manager at Schur Flexibles, reports similar experiences: "Certificates from Recyclass, Interseroh, and Cyclos-HTP are often seen. Each of these certificates chooses a different approach and accordingly offers different perspectives." The company has therefore built up extensive knowledge and databases relating to recyclability. This covers the whole of Europe and a number of non-European countries. Essential building blocks are laws. "Since not all EU member states have currently enacted laws, a good alternative is to follow guidelines, such as those issued by Ceflex, which represents more than 170 partners in the value chain. From raw material producers, processors to brand manufacturers, supermarket chains, recyclers and also NGOs," Wolfmaier advises. The tool of the start-up Recyda is completely new. It provides comprehensive information on recyclability in different countries in a clear and concise manner.

Who packs in a recyclable way?

So what does recycling-friendly packaging look like, and where are there already products on the market that have been modified to improve recyclability?

Henkel plans to switch its entire tube portfolio for dental care products to fully recyclable tubes from its packaging partner Albéa.
Henkel plans to switch its entire tube portfolio for dental care products to fully recyclable tubes from its packaging partner Albéa.

(Bild: Henkel)

In principle, white, uncoloured packaging made of PP or PE is considered a mono-material and is therefore recyclable. Assignment to a recycling path is possible in the sorting process because white material absorbs near-infrared rays and can thus be separated from other packaging. The labelling must also be correspondingly small so that the packaging is recognised as PE or PP in the sorting process. If the white packaging is recycled, it can be used to make granules that can be coloured as desired when recycled.

To make their toothpaste tubes more sustainable and recyclable, companies like Henkel and Procter & Gamble rely on Albéa's Greenleaf tube technology. The packaging is fully recyclable in established collection systems: the new HDPE tubes offer comparable product protection to those currently in use and have received certification from relevant North American and European bodies that they are compatible with existing recycling technologies. Until now, HDPE was considered too rigid to make a squeezable toothpaste tube. To date, toothpaste tubes have typically consisted of multiple layers and types of plastic laminate, as well as a thin layer of aluminium inside to protect the product. Because the entire mix of materials is pressed together into a single film, it has not been possible to separate and recycle them again using conventional methods.

 

Around 80% of all packaging material is unprinted and can be recycled without any loss of quality.
Around 80% of all packaging material is unprinted and can be recycled without any loss of quality.

(Bild: Werner & Mertz)

How a stand-up pouch made of PE shows what is feasible in terms of recycling technology

Werner & Mertz proves that recycling-friendly packaging design has long been possible. For years, the company has been using transparent or white bottles that are completely recyclable, and pays specific attention to the sustainable selection of printing inks, labels and closures. In 2019, the Mainz-based eco-pioneer has launched a new stand-up pouch for its Frosch brand detergents and cleaners that can be fully recycled. The bag is made of 100% recyclable polyethylene, so it contains only one type of plastic. In addition, the printed outside is not glued to the unprinted inside of the bag. During recycling, the printed part ends up in a dark fraction, the unprinted part in a transparent fraction. A full 85 % can thus be recycled as high-quality, transparent material that is equal in quality to virgin material. The remaining 15 % can also be recycled thanks to recycling-friendly printing inks.

New monomaterial polypropylene (PP) solution for Knorr dry soup powder replaces multi-material laminate.
New monomaterial polypropylene (PP) solution for Knorr dry soup powder replaces multi-material laminate.

(Bild: Mondi)

Food packaged sustainably

In the dry soup range, Unilever is partnering with Mondi to supply an innovative new polypropylene monomaterial solution for Knorr dry soup powder in Turkey. The new packaging preserves the shelf life of the food product and does not affect the machinability in production. In addition, the recyclability of the packaging material developed by Jindal has been certified by the Cyclos-HTP Institute. This new packaging solution has been introduced for selected Knorr designs in the Turkish market and Unilever is now considering using it for other product ranges of the brand.

The German Packaging Award went to Schur Flexibles' Mono-Flow system. The recycling-friendly tubular bag made of polypropylene for packaging minced meat replaces the previous PP trays with PET/PE lidding films, which are difficult to recycle, and also saves about 60 % plastic material. Nevertheless, it meets the high barrier requirements for fresh minced meat.

How does mono-material behave on packaging machines?

A close exchange in the supply chain between material, food and packaging machine manufacturers is imperative in order to identify problems at an early stage. After all, how can mono-materials be processed on packaging machines without any problems? Do the new materials run as fast as conventional films? Is the flexibility of the machine limited by recyclable materials? What developments are necessary, on the machine and material side?

Mono materials often consist of a more temperature-sensitive carrier layer than composite films, so it can easily lead to defective sealing seams. The extended stroke length of Syntegon's Amplified Heat Sealing technology allows for extended sealing time on horizontal form fill and seal machines, especially suitable for mono materials, which are therefore faster to process. "Sustainable packaging made of paper and mono materials is in vogue. Our retrofit kit enables customers to switch to sustainable packaging materials such as cold-sealable paper - without speed or format restrictions," explains Christoph Langohr, Project Manager Sustainability Horizontal Packaging at Syntegon Technology.

Use of recyclates in packaging

So there they are, the easily recyclable plastic packaging. But where to put the recyclate? In the sense of an optimally functioning material cycle, they should be used again for the production of packaging. However, there are restrictions on the use of recyclates in food packaging. With the exception of rPET, which is used in beverage bottles and thermoforming sheets, there are currently no other types of plastics approved for food contact. The European Food Safety Authority is responsible for this approval. "It is much more difficult for us to use recycled plastic in food packaging; there are still legal issues to be clarified," confirms Konstantin Bark, Director Sustainable Business & Communications at Unilever. Separate PET collections have so far been the only PCR resource for food, as they are the only way to ensure food safety.

In order to increase the amount of rPET used for food contact material, the German Packaging Institute believes that it makes sense to ensure that material from non-returnable PET bottles does not end up in textiles. "In addition, extending the mandatory deposit to PET trays for eggs, fruit, vegetables or baked goods is worth considering," suggests Kim Cheng, DVI managing director. "In using more recyclate, what we need most of all is more support and paving the way by policy makers and regulators. Because recycled plastic can do much more than just flower pots and park benches. The greatest and most sustainable opportunities lie in the area of food packaging. This is where we can really turn a big wheel in terms of circularity if the necessary certifications and approvals take place."

A study by the Gesellschaft für Verpackungsmarktforschung (Society for Packaging Market Research) commissioned by the climate protection offensive of the retail sector also comes to the conclusion that many more recycled plastics could be used for packaging in Germany. Condition: more high-quality recyclates on the market and fewer legal hurdles for their use. The study shows that only 10% of plastic packaging has no to low barriers to the use of recyclates.

"Binding and reliable quality standards must be established for the use of recycled plastics so that they can be used more extensively than before," says Stefan Genth, Chief Executive at the German Trade Association. "Especially in the case of food packaging, we also need a fast, unbureaucratic approval procedure for recyclates with food contact." Repeatedly discussed political requirements for a minimum recyclate content in packaging would additionally exacerbate the scarcity of recycled material and drive up prices.

Why recyclates are more expensive than virgin material

Recycled plastic is hardly competitive because the low price of oil means that the price of primary plastics is often lower than that of secondary plastics. Konstantin Bark, Unilever, clarifies: "The price of crude oil has dropped due to the pandemic, which of course also affects the price of virgin plastic relative to recycled plastic. Anyone who remains committed to a sustainability agenda needs to know that this comes with investment."

Norbert Völl, press spokesman for Duales System Deutschland, explains the dilemma: "Customers don't use recycled material at the moment if they can buy virgin material cheaper. Even in the case of simple qualities, where the price is still below that of virgin material, one can see that the falling price of virgin material is also putting pressure on the price of recyclates, although there is no direct connection. The cost of recycled material is measured quite differently. However, buyers often insist that the gap between the cost of recycled and virgin material be maintained. This means that if the price of virgin material drops by ten per cent, this is also reflected in the price of recycled material. Although the price of virgin material depends on the price of oil, the price of recycled material does not.

 

Über die Autorin
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Eva Middendorf

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