The Rigid to Flexible Evolution

The most important question in packaging procurement is no longer "which converter do I use" but "which substrate format will my category be in five years from now". The answer for most consumer-facing categories is now visible, and the answer is more flexible than it has ever been.

The premise the industry got wrong

For two decades, the packaging industry told a simple story about itself. Rigid was for premium and shelf-stable applications, where brand experience and barrier performance mattered. Flexible was for everything that needed to be cheap, light, or printed at low cost. The two formats coexisted in a comfortable equilibrium, and procurement teams managed them as separate categories with separate supplier panels.

The equilibrium has broken. Through 2024-2025, the boundary between rigid and flexible packaging started to migrate at a pace that has surprised both packaging executives and the procurement teams that buy from them. The migration is now wide enough, fast enough, and structurally durable enough that any category manager whose strategy was built on the old equilibrium needs to reassess.

This piece argues three things. First, the rigid-to-flexible shift is real, large, and accelerating, not the cyclical or hype-driven story that flexible has occasionally claimed in the past. Second, the dominant narrative for why the shift is accelerating ("sustainability") is partly wrong, and the actual drivers matter for how procurement teams should respond. Third, the regulatory inflection now arriving under EU PPWR is going to reverse some of the trend in specific sub-categories, and the buyer who reads the regulation correctly will pull cost-out from the reversal that the buyer who reads it wrong will miss.

The macro shift, by the numbers

Global packaging is a USD 1.0-1.1 trillion category in 2025, with rigid packaging (bottles, jars, tubs, pumps, dispensing closures, rigid trays) accounting for approximately USD 580-620 billion and flexible packaging (films, pouches, bags, sachets, lidstock) accounting for approximately USD 240-260 billion. The remainder is industrial packaging, corrugated, glass, metal, and paper applications outside the consumer-facing core.

The trajectory matters more than the snapshot. Through 2018-2022 the gap was widening: rigid grew at approximately 3% CAGR, flexible at approximately 4%. Through 2023-2025 the gap has narrowed dramatically: rigid has slowed to approximately 2.5% CAGR, flexible has accelerated to approximately 5.5%. Our base case forecast through 2030 puts rigid at 2.0% CAGR and flexible at 5.5%, implying the two markets converge in absolute revenue terms by 2028-2029.

Two observations from this trajectory matter for procurement. First, the convergence year is not 2035 or 2040; it is 2028-2029. That means any 5-year sourcing strategy written today must assume that the two categories are roughly the same size, not the asymmetric position they have held historically. Second, the slope difference is not narrowing through the forecast period. If anything, it is widening through 2030 as PPWR implementation forces consumer-goods customers to make platform-level decisions that disproportionately favour the flexible substrate.

Counterview on consensus. The current third-party consensus puts flexible CAGR closer to 6.5-7.5% through 2030. We don't see the case for that velocity. The consensus is anchored on the e-commerce demand impulse from 2020-2022 that has since plateaued, and overstates how quickly consumer packaged goods companies can reformulate for shelf-stable performance in flexible substrates. Our 5.5% base case sits below consensus because we expect 50-100 basis points of headwind from PPWR-driven reversals in specific sub-categories (more on this below).

Why is the shift accelerating

The consumer-goods industry talks about the rigid-to-flexible shift almost exclusively in sustainability terms. This framing is wrong, or at least incomplete enough that following it produces bad procurement strategy. The actual drivers, in order of magnitude, are different.

First, the cost-per-gram-of-product-delivered economics. A typical flexible stand-up pouch for a 250ml liquid product uses 4-6 grams of polymer film. A typical 250ml rigid bottle with closure uses 18-25 grams of polymer. At parity HDPE/PP pricing, the material cost differential alone is approximately 65-75% in favour of flexible. Add conversion economics (flexible converting is faster and less capital-intensive per unit) and the total finished-goods cost differential widens to 35-50%. For categories where the brand can convince consumers to accept a flexible format, this is decisive.

Second, the freight and warehouse economics. Flexible packaging ships and stores at approximately 5-10x the volumetric density of rigid packaging. For e-commerce fulfilment, where dimensional weight pricing dominates inbound freight cost, the flexible-format saving can exceed the material-cost saving. Our channel checks with large North American consumer-goods customers put the all-in freight-plus-warehousing benefit at 10-15% of total landed cost for switched SKUs.

Third, the e-commerce optimisation pull. Amazon's Frustration-Free Packaging programme, and equivalent direct-to-consumer transit standards, structurally favour formats that ship with high volumetric density, do not require shrinkwrap, and survive ISTA-3A drop testing without crumple zones. Flexible formats have a structural advantage on the first two and a manageable disadvantage on the third (managed via top fitments and gusset designs).

Fourth, the brand-experience evolution. Through 2018-2022 brand managers in personal care and household care still treated rigid bottles as the default premium-experience substrate. Through 2023-2025 they have started treating well-designed flexible pouches as comparable or superior on shelf, particularly in refill-format SKUs where rigid is held as the durable "system" and flexible as the consumable refill. Refill formats have moved from sustainability-niche to mainstream channel positioning in fewer than three years.

Fifth, and only fifth, the sustainability tailwind. Flexible packaging genuinely uses less material per unit of product delivered, and that material reduction is the single biggest lifecycle-assessment improvement available in most consumer categories. But flexible packaging is also harder to mechanically recycle than rigid, particularly multi-material flexible structures, and the regulatory environment under EU PPWR is now starting to penalise that recyclability gap. The sustainability story for flexible is therefore real but more complicated than the consumer-goods industry has acknowledged.

The order matters. If you treat sustainability as the primary driver of the rigid-to-flexible shift, your sourcing strategy will overweight PCR-content negotiations and underweight the cost-out levers that come from the freight-and-warehouse benefit. If you treat cost and e-commerce as the primary drivers, your sourcing strategy will look very different, and will be more correct for most categories.

Sub-segment winners and losers

The aggregate trajectory hides important sub-category variation. Some sub-categories are converting from rigid to flexible at roughly the headline 5.5% velocity. Some are converting much faster. Some are reversing. The procurement-decisive question is which bucket your category is in.

The fast-converters tell one story; the reversals tell a different and equally important story.

Single-serve beverage concentrates have been the headline of the rigid-to-flexible shift. Stand-up pouches with screw-cap fitments now occupy approximately 35-40% of single-serve beverage volume in 2025, up from less than 15% in 2018. The next five years are expected to extend that to approximately 55-65% as North American and European brands follow the conversion path that Asian markets pioneered. For procurement teams sourcing rigid bottles for this category today, the strategic question is not "should we transition" but "how fast and through which contract structure".

Household care refills are the more interesting development because the conversion happened faster than the industry expected. Refill-format positioning was treated as a sustainability niche through 2020-2022; by 2025 it is a mainstream pricing position with 40-50% household-care category penetration in EU markets and 25-35% in North America. The procurement implication is that converters who built rigid-only capacity into 2022 are now over-invested in the wrong substrate.

Pharma and medical primary packaging is the major reversal, and it is structurally durable. Drug stability requirements, regulatory approval cycles, and tamper-evident standards keep this category in rigid for the foreseeable future. Buyers in pharma packaging should expect their substrate mix to look largely unchanged in 2030 compared to 2026, despite the macro pressure on rigid overall. This sub-category is one of the few where the procurement strategy can safely ignore the headline rigid-to-flexible narrative.

PPWR-recyclability-sensitive SKUs are the underappreciated reversal. Multi-material flexible packaging (typically a metallised film laminate with barrier layers) is the technically simplest flexible format but is also the format hardest to recycle. Under PPWR's recyclability-by-design thresholds (entering definitive regime from 2026), multi-material flexible packaging faces substantial EPR fee uplift and, in some member states, outright phase-out by 2030. The buyer response, particularly in non-food categories where barrier requirements are less demanding, has been to re-substrate back to mono-material rigid where the recyclability picture is cleaner. This is the rigid-to-flexible-to-rigid-again whiplash that the consensus narrative misses.

The cost-economics case

Procurement teams who have already started the conversion report consistent, structural cost-out at the SKU level. Our channel checks across nine large consumer-goods customers suggest a typical conversion delivers 25-40% all-in landed-cost reduction on the converted SKU within 12-18 months of full transition. The components decompose roughly as follows:

Cost component	Saving range	Notes
Polymer material	50-65% reduction	4-6g flexible vs 18-25g rigid for same product volume
Conversion economics	15-25% reduction	Higher line speeds; lower tooling cost per SKU; faster changeovers
Inbound freight	10-15% reduction	5-10x volumetric density advantage
Warehouse storage	8-12% reduction	Same density advantage applied to inventory days
Retail labour	3-5% reduction	Faster shelf replenishment; pallet density
Total landed cost (typical SKU)	25-40% reduction	Net of conversion investment amortisation

The conversion investment matters. Net savings only show up after the brand owner has amortised the conversion cost: typically USD 250K-1.2M per SKU for tooling, qualification, ISTA testing, and brand-design rework. The 12-18 month payback assumes high-volume SKUs (>5M units/year); smaller-volume SKUs may not pay back at all. This is where the procurement decision separates from the brand decision: brand owners often want to convert SKUs that economically should stay in rigid because the conversion volume is too low. Procurement should push back on those conversions.

Counterview on the cost case. The 25-40% landed-cost reduction band is real but is anchored on the highest-volume, highest-velocity SKUs in the brand-owner portfolio. For the long tail of mid-velocity and low-velocity SKUs, the actual saving compresses to 8-15%, and the conversion may still be net-negative once one-time investment is properly amortised. Procurement teams that have run the math on a representative sample of 50-100 SKUs typically find that 30-40% of the portfolio is not economic to convert at current resin and freight prices, and another 20-30% is marginal. Plan SKU prioritisation accordingly.

The sustainability paradox

The flexible-packaging industry has, until recently, presented itself as the obvious sustainability winner. Less material, less freight, less warehouse space. The story is genuine, but the regulatory environment has now started to qualify it in important ways.

EU PPWR (entering definitive regime from August 2026) introduces three constraints that interact with the rigid-to-flexible decision. First, all packaging placed on the EU market must meet recyclability-by-design criteria by 2030, with progressive thresholds before then. Second, EPR fees become higher and more graduated by recyclability tier, where easier-to-recycle formats pay less, harder-to-recycle formats pay more. Third, certain material structures (including some multi-material flexible structures) face restrictions or outright bans in specific member states.

The result is that mono-material flexible structures retain their cost-and-freight advantage and now also retain their sustainability advantage. But multi-material flexible structures lose much of their cost advantage as EPR fees rise and member-state restrictions tighten, and lose their sustainability advantage outright. The procurement-relevant question becomes which mono-material flexible structures can deliver the barrier performance required for the application.

For food categories with high barrier requirements (frozen, ambient long-shelf-life, oxygen-sensitive), the mono-material answer is constrained. Mono-material polyolefin films do not yet match the barrier performance of metallised laminates, and the gap is shrinking only slowly. Mono-material PE/PP with barrier coatings (silicon oxide, aluminium oxide) is the most credible path forward, but qualification cycles are 18-30 months and supply is concentrated.

For non-food categories with moderate barrier requirements (personal care, household care, dry goods), the mono-material flexible answer is increasingly viable today. Aptar, Berry-Amcor, Mondi, and Constantia all have mono-material flexible product lines in commercial production, and pricing is converging with the conventional multi-material laminate.

The procurement implication is split by barrier requirement. If your category has a moderate barrier requirement, you can extract the full cost-out of the rigid-to-flexible conversion using mono-material flexible formats that also satisfy PPWR. If your category has a high barrier requirement, you face a structural choice between staying rigid (preserving mono-material recyclability), converting to multi-material flexible (taking cost-out now but facing rising EPR fees), or waiting for mono-material flexible barrier capability to mature (preserving optionality at the cost of capital deployment timing).

The supplier landscape, after the merger

The packaging supplier landscape has consolidated dramatically through 2023-2025, and procurement teams should not assume the playbook of the previous decade still applies.

The Berry-Amcor merger closed 30 April 2025 (~USD 9B equity value, NYSE: AMBP) and created the largest global packaging conglomerate by revenue, spanning rigid and flexible formats in approximately balanced proportion. The strategic logic is exactly the rigid-to-flexible shift we have been discussing: by combining a flexible-heavy Amcor with a rigid-heavy Berry, the merged entity captures the substrate substitution wherever it happens within the customer's portfolio, rather than losing one to lose the other. This is structurally bad news for category managers who relied on cross-supplier negotiation between rigid-only and flexible-only suppliers.

Mondi and Constantia remain the European flexible-packaging anchors. Mondi (LON: MNDI) generated approximately USD 8.5B in 2025 revenue with deep integration from kraft paper through to flexible converting; Constantia generated approximately USD 1.6B. Both have committed to mono-material flexible product lines and are positioning explicitly against the PPWR-driven reversal in multi-material flexible.

Sealed Air and Sonoco retain North American flexible-and-rigid presence with somewhat softer overall growth than the larger conglomerates. Sealed Air (NYSE: SEE) generated approximately USD 5.4B in 2025 revenue; Sonoco (NYSE: SON) approximately USD 6.8B. Both have repositioned around protective packaging and food applications, leaving more of the consumer-goods conversion-cycle work to the larger players.

Aptar Group sits adjacent to the rigid-to-flexible debate, focused on dispensing closures and pumps. Aptar's positioning has become subtle and interesting: rather than choosing between rigid and flexible, Aptar is building closure and dispensing systems that work across both substrates. The 28/410 closure that fits on a rigid bottle today is being engineered to fit on the top fitment of a flexible pouch tomorrow. Procurement teams sourcing dispensing closures should expect their supplier list to look largely unchanged across the rigid-to-flexible shift.

Mid-tier and challenger suppliers face the most difficult positioning. Companies that built capacity around rigid-only or flexible-only platforms in 2018-2022 are now under strategic pressure to extend across formats or accept share loss. Expect 3-5 mid-tier acquisitions in 2026-2027 as the larger conglomerates buy capability gaps.

What procurement teams should do

The strategic question is no longer whether the rigid-to-flexible shift is real but how to position the category procurement portfolio to capture cost-out while managing the PPWR-recyclability constraint. Six recommendations.

First, segment the portfolio by conversion economics not by substrate. Build a SKU-level view of each category that shows volume, conversion investment requirement, payback period at current resin and freight prices, and PPWR-compliance status. High-volume SKUs with strong payback economics and PPWR-clean conversion paths are immediate conversion candidates. Low-volume SKUs, regulatory-anchored SKUs (pharma, medical), and brand-experience-anchored SKUs (premium spirits, prestige beauty primary) should stay rigid. Mid-volume SKUs need case-by-case analysis.

Second, write contracts that allow substrate optionality. Multi-year supply agreements signed in 2026 should include explicit substrate-flexibility clauses: the supplier commits to volume at a SKU level but pricing is indexed by substrate so a mid-contract conversion does not require a renegotiation. The post-merger Berry-Amcor and Mondi-Constantia tier-1 suppliers are willing to accept this clause because it aligns with their cross-substrate strategy. Mid-tier suppliers may push back; that pushback is itself useful information about supplier strategic positioning.

Third, qualify mono-material flexible suppliers ahead of need. The PPWR-driven shift to mono-material flexible structures is creating a 12-24 month supplier-qualification window where capacity will be tight and pricing will be elevated. Procurement teams that pre-qualify mono-material flexible suppliers in 2026, ahead of the conversion peak in 2027-2028, will pay 15-25% less per pouch than teams that qualify reactively.

Fourth, manage the rigid-tail strategically. The 30-40% of the rigid portfolio that does not economically convert should be consolidated onto fewer SKU platforms, fewer suppliers, and longer contract terms. Rigid converter consolidation is freezing capacity for the largest customers; buyers who are not on the customer lists at Berry-Amcor and Silgan Dispensing will see rising rigid pricing through 2028. Lock 24-36 month volume commitments on the rigid SKUs you are keeping.

Fifth, do not optimise for sustainability alone. The sustainability optimisation question has been complicated by PPWR. A mono-material rigid bottle may have better lifecycle outcomes than a multi-material flexible pouch in some categories. A mono-material flexible pouch may have better lifecycle outcomes than a mono-material rigid bottle in others. Procurement teams that rely on a generic "flexible is more sustainable" heuristic will make sub-optimal substrate decisions. Build a category-specific lifecycle analysis using the brand owner's actual material and freight footprint.

Sixth, watch the regulatory pipeline beyond PPWR. The UK is finalising parallel EPR frameworks; Australia is implementing its 2030 packaging targets; Canada has a province-by-province patchwork; California, Washington, and New York are advancing state-level frameworks in the US. The procurement-decisive question is whether your category will face globally consistent recyclability standards or fragmented region-by-region standards. The latter creates additional procurement complexity but also creates regional sourcing arbitrage that the well-positioned buyer can capture.

The five-year view

By 2030, three things will be true that are not true today.

First, the rigid and flexible packaging markets will be approximately equal in size. The convergence year is 2028-2029 in our base case. By 2030, flexible will be the larger market in volume terms even if rigid retains modest premium pricing in some categories.

Second, mono-material flexible formats will dominate the flexible category. Multi-material flexible structures will retain share in high-barrier food applications where mono-material alternatives have not matured, but for most consumer-facing applications, mono-material polyolefin films with barrier coatings will be the default substrate.

Third, the supplier landscape will be more consolidated than today. Post-Berry-Amcor, the next round of Tier-1 consolidation is likely to involve Mondi, Sealed Air, or Sonoco as either acquirers or targets. By 2030 expect 4-5 global packaging conglomerates with USD 15B+ revenue each, plus 8-12 regional mid-tier specialists.

For procurement, this means the cost-out and risk-management opportunities of the rigid-to-flexible evolution are largest in the next 24-36 months. After that, the supplier-side pricing power that comes with consolidation will compress the gains available to buyers. The window for proactive repositioning is now.

Final analyst take. The rigid-to-flexible evolution is the largest single secular shift in consumer-goods packaging since the move from glass to plastic in the 1980s. It is bigger than the sustainability discourse has framed it, more cost-driven than the consensus has acknowledged, and more substrate-specific than the headline numbers suggest. Procurement teams who treat it as a sustainability initiative will miss the cost-out. Procurement teams who treat it as a generic substrate switch will miss the PPWR-driven reversals. The right framing is portfolio-by-portfolio: which SKUs convert, which stay rigid, and which need PPWR-clean conversion paths. The teams that do this well will outperform their peers on category cost-out by 8-12 percentage points through 2030. The teams that do not will end up with the wrong substrate mix at the wrong moment in the consolidation cycle.

---

This piece is part of the Claight Hub Thought Leadership series. Published 29 May 2026.