Why monomaterial is not immediately dominant everywhere despite PPWR
The PPWR calls for “design for recycling” – and the direction is clear: packaging should be designed in such a way that it can be collected, sorted, and recycled to a high standard in practice. Monomaterials are often the most direct way to achieve this because they function most robustly in existing mechanical material flows. Nevertheless, complex multilayers still dominate supermarket shelves. This is rarely due to a lack of will, but rather to a technical interplay of polymer physics, filling line reality, and sorting and recycling practices. Those who understand these hurdles can develop targeted solutions that ensure product protection and process capability – while consistently moving toward recyclable designs.
Recyclability is a chain – not a label
It is important to note that recyclability is not simply a label that can be stuck on a material. It is the result of a chain of design, identification/sorting, and recovery—and it must work on an industrial scale. A practical rule of thumb is therefore: recyclability is the product of sortability, recyclability, and recyclate quality. It is precisely at this interface that the monomaterial dilemma arises, because any change in the material structure immediately has repercussions on product protection, process windows, and recycling streams.
Hurdle 1: Barrier physics – product protection vs. recyclable structures
The first and often most significant hurdle is the physics of barriers. Here, the rule is: physics cannot be argued away. Polyolefins such as PE or PP are excellent water vapor barriers, but comparatively permeable to oxygen. This is crucial for many food and sensitive applications because oxygen drives the oxidation of fats, loss of aroma, or degradation of sensitive ingredients. In many cases, barriers such as EVOH, PA, or certain coating systems are therefore needed to reliably achieve the required shelf life and product safety. At the same time, barriers and functional layers can influence recycling behavior because they have different thermal and rheological properties. The right approach is therefore not “barrier at any price” or “mono at any price,” but rather an engineering-driven change in objectives: clearly define barrier requirements, minimize barrier components, examine more compatible setups, and, where possible, transfer barrier functions to more recycling-friendly structures. It is crucial that the changeover is data-driven: with clear target values for product protection and a structured assessment of the impact on the target stream.
Hurdle 2: Filling line – the process window is decisive
The second hurdle lies where theory fails in reality: on the filling line. Packaging is not created in the laboratory, but often on form-fill-seal lines – and that’s where the process window counts. Multilayer structures often use heat-stable outer layers so that the sealing tool does not stick, while reliable sealing can be achieved at lower temperatures on the inside. This enables high cycle rates with stable seam quality. With pure PE, the outer and inner layers are thermally closer together; the process window shrinks, temperature and pressure sensitivity increase, and the risk of sticking, unstable seals, or increased scrap increases. This is precisely where it is decided whether a mono solution is industrially viable. Therefore, the material and machine must be optimized and validated together. “Recyclable on paper” is of no help if the line loses significant performance or quality costs skyrocket. The changeover requires a robust process window – and this is achieved through targeted material selection, sealing layer concepts, oriented films where necessary, and clean line validation.
Hurdle 3: Sorting and recycling – detection, density, components
The third hurdle is the sorting and recycling dilemma. Technically, packaging is only recyclable if it is sorted correctly and can then be recycled. Problems often arise during sorting due to design decisions that make the packaging “invisible” to detection systems: full sleeves made of foreign materials, unsuitable colors, or problematic combinations can interfere with NIR detection and lead to misplaced waste in the wrong fractions. There is a classic problem lurking in recycling that is often underestimated: density. Polyolefins are typically lighter than water and float, which means they can be separated cleanly in the float-sink process. However, if high filler contents are used, the density can rise above 1 g/cm³. The material then sinks, is discharged together with impurities, and does not end up in high-quality recycling. This leads to a hard but helpful rule: it is not only the base polymer that matters, but also additives, density, label and sleeve design, and their separability. If you really want to implement “design for recycling,” you have to protect the main body—anything that makes it unsortable or contaminates the recyclate is a real risk.
Hurdle 4: Cost-effectiveness and material efficiency – when “mono” means more mass
The fourth hurdle concerns cost-effectiveness and material efficiency. Some multilayers are material-efficient in practice because they achieve the same barrier or stiffness as a significantly thicker monofoil despite being thinner. An ill-considered change can therefore lead to more plastic being used to achieve the same performance – with implications for costs, material usage, and carbon footprint. The right approach is to make a systematic comparison: Which solution fulfills the function, remains machine-compatible, achieves the required recyclability—and does so with as little material as possible? It is precisely these trade-offs that must be calculated transparently and solved technically, otherwise the material decision becomes a matter of faith.
Technical solutions – effective, but never without trade-offs
There are technical solutions, but they rarely come without side effects. Oriented polyolefin films can improve properties and machine runnability, but they must be suitable in terms of availability, cost, and validation effort. Thinner, targeted functional layers or more recycling-friendly barrier setups can help to minimize disruption to target streams, but they require careful consideration of boundaries and consistent quality testing. Coatings can provide strong barriers, but depending on the application, they are sensitive to stretching, folding, or robustness. Compatibility and intelligent design only work if they are resilient in the real process window and in the target stream. The decisive factor is therefore not whether a technology exists, but whether it really works in your specific application—product, line, and disposal reality.
Technical documentation as a transformation tool
This brings us to the key point: under PPWR, technical documentation is transformed from a “paper file” into a transformation tool. Not to justify complex composites, but to make the transition manageable. Good documentation translates requirements into engineering decisions: Which product and barrier requirements are non-negotiable? Which parameters dominate the process window on the line? Which design factors determine sorting and recycling? Which alternatives have been tested, with what results, and which solution offers the best combination of product protection, process capability, and recycling performance? Using documentation in this way establishes a robust basis for decision-making in development, purchasing, and production—while also creating verifiable evidence of compliance and internal approvals.
The practical way: From portfolio to roadmap
In practice, this leads to a clear roadmap. First, the portfolio is segmented: Which packaging is already close to a robust design for recycling, which is technically convertible but needs design or line optimization, and which is challenging because barriers or applications place high demands on it and therefore require development work. Next, the database is neatly structured: material composition with layer thicknesses, additives, and colors; barrier and shelf life targets; line parameters such as cycle rate, seal type, temperature window, and typical reject patterns; and all components such as sleeves, labels, and closures, including separability. This is followed by a material and design screening that not only evaluates alternatives but also validates them – with the aim of creating a roadmap that brings together engineering, line and recycling logic. The benchmark is always the same: the solution must work in the real chain – from the product to the line to the target stream.
Conclusion: Monomaterial is the ideal solution—but it’s not a sprint
The conclusion is clear: monomaterial is often the ideal solution—but the transition is not a sprint. Barrier physics, machine windows, sorting reality, and material efficiency determine the pace. Those who analyze, test, and document in a structured manner now will make the transition controllable, reduce friction in production, and minimize subsequent compliance and cost risks.
PPWR portfolio check: How we support you
If you want to set up your portfolio in a technically sound manner, we can support you with a PPWR portfolio check. We use gap analysis to identify which packaging is already robustly recyclable and where the biggest technical hurdles lie. We structure requirements and evidence in such a way that material and design decisions can be made quickly and reliably. And we examine alternatives—such as oriented films, barrier setups, or sleeve/label optimizations—using a decision matrix that combines product protection, process windows, and recycling performance. Prepare your portfolio for 2030 and beyond: Contact us for a no-obligation portfolio check—including quick wins, a roadmap, and the next three technical steps for each type of packaging.
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