Plastic isn’t disappearing, but it is being re-engineered

Mono-PE and mono-PP structures are being developed to make flexible packaging more compatible with mechanical recycling. But replicating the performance of conventional multilayer laminates — and ensuring redesigned packs are actually recycled — remains a complex engineering challenge.

Plastic packaging is not going away. Instead, one of the industry’s most significant design shifts is taking place inside the material itself, as complex flexible structures are increasingly redesigned around mono-polyethylene (mono-PE) and mono-polypropylene (mono-PP).

The objective is not simply to use less plastic. It is to develop packaging that retains the strength, sealability and barrier performance needed to protect products while making the structure more compatible with recycling.

For flexible packaging, that is a significant engineering challenge.

Multilayer structures exist because different materials perform different functions. Replacing them means finding new ways to deliver those properties without creating packaging that is difficult to sort or recycle after use.

Regulation is adding urgency. The EU’s Packaging and Packaging Waste Regulation (PPWR) entered into force in February 2025 and generally applies across the EU from 12 August 2026. It establishes new requirements designed to improve packaging recyclability and increase the use of recycled plastic, with detailed design-for-recycling criteria and major recycled-content requirements taking effect from 2030.

For packaging manufacturers, converters and brand owners, recyclability is consequently moving from a sustainability objective towards a fundamental part of the product design brief.

Why multilayer packaging is difficult to replace

Flexible packaging is highly effective partly because manufacturers can combine materials with different properties in a lightweight structure.

A single pack may require mechanical strength, reliable sealing and protection against oxygen, moisture, aromas, grease or light. Conventional multilayer laminates can meet these requirements by assigning different functions to different materials.

The difficulty comes when the package reaches the end of its useful life.

When polymers and other materials are permanently combined, conventional mechanical recycling processes may struggle to separate them or produce a consistent recycled material.

Mono-material packaging approaches the problem differently. Rather than eliminating multiple layers altogether, developers can build structures from layers based predominantly on the same polymer family.

That distinction matters. Mono-material does not mean single-layer. A mono-PE or mono-PP flexible pack can contain several functional layers, provided the overall structure remains compatible with its intended sorting and recycling route.

The latest Designing for a Circular Economy (D4ACE) guidance from CEFLEX places strong emphasis on mono-PE and mono-PP structures, alongside requirements covering other components that influence sortability and mechanical recyclability.

Its updated guidance is underpinned by a testing programme conducted between 2022 and 2024 that assessed more than 600 flexible-packaging samples and generated more than 1,700 data points across 55 materials and components.

The challenge for packaging developers is therefore not simply to eliminate multilayers. It is to reproduce their functionality within structures better suited to recycling.

The engineering challenge behind mono-PE and mono-PP

PE and PP are already widely used in flexible packaging, making them natural candidates for redesign. But converting a mixed-material laminate into a mono-material structure is not a straightforward film substitution.

Packaging engineers may need to reconsider film orientation, coatings, adhesives, printing systems and sealing technology. Properties previously provided by a separate material increasingly have to be engineered into a predominantly PE- or PP-based structure.

Barrier performance is among the biggest challenges.

Food, pet food and other sensitive products may require protection against oxygen, moisture, aromas or light. Removing an effective barrier material can be counterproductive if it results in shorter shelf life or greater product waste.

The aim is therefore not to eliminate barrier packaging, but to deliver the required performance while keeping the overall structure compatible with its intended recycling process.

That is increasing the importance of film engineering, coatings, adhesives and other technologies that can add functionality without undermining recyclability.

CEFLEX’s D4ACE guidance reflects this complexity. Its recommendations consider barrier layers, coatings, adhesives, inks, metallisation and other components rather than treating the base polymer as the sole determinant of recyclability.

Packaging performance and end-of-life requirements increasingly have to be engineered together.

Mono-material does not automatically mean recyclable

The shift towards mono-material packaging comes with an important qualification: calling a pack “mono-material” does not automatically make it recyclable.

Printing, pigments, adhesives, coatings, labels, closures and barrier materials can all affect sorting, reprocessing and the quality of the resulting recyclate. The size and shape of flexible packaging can also influence whether it is successfully captured by sorting equipment.

This is why the industry’s focus is moving beyond material selection towards design for recycling.

The principle is straightforward. Packaging needs to be designed not only around the material it contains, but around the recycling process it is expected to enter.

Choosing PE or PP may therefore be the starting point, but it does not settle the recyclability question.

The complete packaging structure has to be considered.

Designing for recycling does not guarantee recycling

There is a further distinction for packaging companies to consider: a package can be designed to meet recycling criteria and still not be recycled in practice.

Collection, sorting and reprocessing infrastructure ultimately determine whether discarded packaging reaches an appropriate recycling facility.

The UK illustrates the challenge. Under the government’s current Recyclability Assessment Methodology (RAM), flexible plastics must be collected by at least 75% of local authorities to meet its “widely collected at kerbside” criterion. The methodology states that no flexible-plastic category currently exceeds a 14% collection rate.

The same methodology shows how material composition can affect reprocessing. Polyolefin flexible packaging must contain at least 80% PE, PP or a combination of the two by weight to be considered for reprocessing under the assessment, while specified materials and components can lead to different classifications.

The distinction underlines a fundamental point: packaging design can improve the prospects for recycling, but it cannot by itself create collection systems, sorting capacity or markets for recycled material.

Recyclability therefore has to be considered as a system rather than simply as a property of a film.

For packaging developers, that means asking whether a pack can be collected and identified, whether its composition is compatible with sorting and reprocessing, and whether the recovered material has a viable route into another application.

Answering those questions requires cooperation across the value chain, bringing together brand owners, converters, film and polymer suppliers, coating and adhesive manufacturers, waste companies and recyclers.

PPWR turns recyclability into a commercial issue

The regulatory environment is making these questions more immediate.

The PPWR generally applies across the EU from 12 August 2026 and establishes a harmonised framework for packaging and packaging waste.

Its recyclability requirements are being introduced through a series of measures and implementation dates. Detailed design-for-recycling criteria and recyclability performance grades apply from 2030, while requirements for recycled plastic content in new plastic packaging also begin from 2030 and increase over time.

For companies supplying European markets, this changes the commercial calculation.

A packaging structure may perform exceptionally well on a production line and provide the required protection on the shelf. But if it cannot satisfy future recyclability requirements, it may ultimately need to be redesigned.

That makes development timelines important.

Changing a flexible packaging structure can involve material trials, barrier and shelf-life testing, filling-line validation, supplier qualification and changes to converting or packaging processes. For companies managing large packaging portfolios, redesigning multiple formats is unlikely to be an overnight exercise.

The regulatory milestones therefore matter well before their respective deadlines arrive. Packaging being developed today may remain in production for years, making future recyclability an increasingly important design parameter.

Performance remains the limit

Despite the momentum behind mono-material flexible packaging, mixed-material structures are unlikely to disappear immediately.

Packaging’s first job remains protecting its contents. A pack that is easier to recycle but fails to provide adequate protection can create other environmental impacts, particularly where weaker barrier performance contributes to food or product waste.

Packaging developers are therefore balancing three requirements: performance, material efficiency and recyclability.

In some applications, mono-PE or mono-PP structures can increasingly satisfy all three. In others, demanding barrier, processing or shelf-life requirements make the transition more difficult.

There is consequently unlikely to be a single mono-material solution for every flexible-packaging application.

Instead, the industry is moving towards a more application-specific approach: simplifying structures where performance can be maintained, while recognising that some products will continue to require more complex constructions.

That makes the transition as much an engineering and innovation challenge as a sustainability one.

The new design brief for plastic packaging

Flexible packaging has traditionally been engineered around what happens before disposal: whether it can be manufactured efficiently, survive distribution, protect its contents and perform on the shelf.

End of life is now becoming part of the same engineering equation.

That does not mean every multilayer structure can be replaced by mono-PE or mono-PP. Some applications still require combinations of barrier and processing properties that are difficult to reproduce within current mono-material designs.

But where performance can be maintained, regulation and recycling requirements are giving packaging developers a powerful incentive to simplify structures and align them more closely with established recycling systems.

For brand owners, converters and packaging manufacturers, the definition of a successful pack is consequently changing.

The next generation of plastic packaging will have to work on the production line, protect the product on the shelf — and work within the recycling system after its first job is done.