Paper, cardboard, and cellulose as alternatives…? Don’t even think about it!
All current—and especially future—packaging applications that use wood and cellulose-based materials depend above all on the availability of a fundamental resource: cellulose pulp derived from forestry operations, which forms the foundation of the entire value chain for this family of materials. Yet growing demand is putting enormous pressure on this resource, which, while renewable, is nonetheless finite at any given moment. And everyone wants wood for all kinds of applications, with packaging representing only a small fraction of that. Overall, to meet the projected increase in demand by 2050, we would need to plant an area equivalent to the size of Australia! And, unfortunately, the image of an idyllic material that would allow us, at the modest cost of converting packaging, to achieve an “environmentally friendly” consumption model is also a utopia! With the aim of helping stakeholders make informed choices without succumbing to passing trends, and after previously analyzing glass and aluminum, Gérald Martines* examines here the case of materials in the paper-cardboard family and, more generally, those based on cellulose pulp... and urges us not to get carried away!
Here, then, is a truly renewable and bio-based material. It is also the only material suitable for packaging that is both recyclable and biodegradable. Because of these advantages, we are witnessing a fundamental shift toward the “paperization” of packaging. Countless initiatives are underway to convert packaging—previously made of plastic, or even glass or aluminum—to a paper-and-cardboard base: cartons, jars, tubes, pouches, refills… This trend, already well established in the food industry, is spreading to the cosmetics sector, which adds formats specific to the industry—such as sticks or cases—to the ones mentioned above; and the “paper bottle” is becoming an industrial reality.
The well-known advantages of materials in this paper-cardboard family (bio-based, renewable, recyclable, compostable) thus point toward an ideal world where a significant portion of packaging would be made from cellulose, where most of the materials produced would be recycled in a fully circular manner, and where any leaks into the environment would be inconsequential since the material is biodegradable…
Consequently, and particularly since the impacts of plastic pollution have been widely publicized, there is strong consumer demand for “paper” packaging, especially as a replacement for plastic, and numerous initiatives are emerging in this direction: suppliers are offering alternative formats to traditional plastic ones (and those made from other materials), and brands are modifying their packaging to incorporate more paper-based formats.
Primary, secondary, tertiary packaging… different constraints.
When considering the uses of paper and cardboard in packaging, we must distinguish between primary, secondary, and tertiary packaging, as each of these areas imposes its own constraints.
Among these three categories, only tertiary packaging (which groups and protects the product throughout the supply chain up to the store shelf, or to the doorstep of e-commerce customers) can be made of a single material and easily recycled in a closed-loop system; this primarily involves plain cardboard boxes, which do not require a “consumer-facing” visual quality; their natural brown-beige color is acceptable, they do not require bleaching, and they are minimally decorated. They already contain a significant proportion of recycled material.
Gérald Martines - IN-SIGNES
Secondary packaging—such as cases, boxes, and blister packs—are important branding elements, as they represent the consumer’s first contact with the product and must therefore be appealing. As such, the material for these packages undergoes numerous “finishing processes”: printing, marking, embossing, lamination, etc., which add pigments, inks, aluminum (for metallic-look markings), plastic films, adhesive, first-use guarantee stickers, RFID chips, and so on. The proportion of post-consumer recycled material is limited due to visual quality requirements. These packages are never reused: they end up in the trash as soon as the product is purchased and unpacked. They are therefore single-use packages with a short lifespan (once in the consumer’s hands). It is this category that contributes most to the perception of waste that consumers may have regarding packaging.
As for primary packaging, it is extremely rare for paper to be used in its raw form. Indeed, the primary purpose of packaging is, as we must remember, to protect its contents. Depending on the specific contents and their particular sensitivities, packaging is required to provide dedicated protective functions against oxidation, light, moisture or drying out, heat, crushing, etc.
We can therefore see that, particularly for primary and secondary packaging, paper and cardboard alone do not provide sufficient performance for many of the expected functions, and that they must be “functionalized”—that is, they must be treated with coatings or additives designed to compensate for, for example, their wettability or lack of waterproofing and barrier properties. And these coatings are, with rare exceptions, polymers (sometimes bio-based, which makes no difference at the end of life), or even PFAS—at least until their recent ban. Packaging that appears to be—or even claims to be—paper or cardboard from the consumer’s perspective is therefore most often a cellulose-plastic composite, or a cellulose-aluminum-plastic composite (this is the case for most food cartons, many pouches, and the recently introduced “cardboard” tubes).
Recyclable!?
Nevertheless, even when functionalized and decorated in this way, paper-based packaging is considered, from a regulatory standpoint, to be recyclable. And of course, marketing capitalizes on this promise. Yet this claim deserves closer scrutiny. In France, to be classified as recyclable, packaging must demonstrate that at least 50% of its weight is recoverable as paper fibers during recycling.
Packaging can therefore claim to be recyclable with only 50% + epsilon of cellulose actually recycled, leaving a residue that can account for up to 50% - epsilon of its mass. This residue contains everything else, including the plastic and aluminum that made up the barrier layers and the decorative layer; it is most often incinerated or sent to landfills. Some food carton recycling facilities are equipped to recover the plastic-aluminum composite, known as PolyAl, which cannot be used for much other than low-value items such as flower pots, low-end garden or community furniture, etc.
It should be noted that there are a small number of facilities specializing in the recycling of multilayer food cartons. In these centers, broadly speaking, the recycling process typically begins by recovering the cellulose pulp fraction from the packaging; the remainder then undergoes a pyrolysis process, in which the polymer fraction is separated and recovered, leaving the aluminum fraction, which is purified and recovered. This is, in fact, a circular process where all components of the package are returned to the cycle (with the exception of inks, pigments, adhesives, etc.), but at the cost of significantly increased energy consumption (particularly during the pyrolysis phase), which makes the process more expensive and reduces its environmental benefit. Furthermore, only a small number of such facilities exist, and they can process only a small fraction of the considerable volume of this type of packaging, most of which continues to be processed by conventional facilities.
We sometimes hear the argument that “the main thing is that [this fraction] is reused,” which emphasizes the importance of not letting it become waste. That’s not wrong! At least at first glance… It should nevertheless be noted that this constitutes “downcycling”, sometimes euphemistically referred to as “open-loop recycling”: that is, the reuse of materials and resources in a degraded form, for an application less valuable than the original one. This fraction cannot be reintroduced as-is into the manufacture of new packaging, which consequently requires a constant influx of virgin materials, even at equal volumes, and all the more so to fuel volume growth. We are therefore not in a circular system. And finally, the volume of PolyAl generated is much greater than what is reused in the form of derivative products. There is therefore a fraction that becomes waste. Not to mention that objects made from PolyAl are not themselves eternal and will sooner or later end up as non-recyclable waste—after releasing, during this second life, numerous microplastics due to wear and tear, UV rays, and weather conditions…
The pouches, refills, samples, etc., used in cosmetics are also multi-layered and incorporate plastic/aluminum films, and face the inefficiency of end-of-life processing for composite objects. Furthermore, this packaging is not suitable for reuse; it is single-use, so its end-of-life flow is equivalent to its market flow.
Finally, it should be noted that substrates made from recycled fibers most often use a fraction of virgin fibers to compensate for the degradation of fibers that have been shortened and broken during the recycling process. For this reason, a flow of virgin inputs is also required. Some socially responsible brands insist on secondary packaging with a high percentage of recycled material, but this necessitates increasing the basis weight of the substrates to compensate for the loss of rigidity due to the degradation of the mechanical properties of the recycled fibers, and the overall balance is often negative.
It is therefore clear that we are far from a circular system and that the use of cellulose-based packaging requires a continuous flow of inputs and symmetrically generates a stream of waste that escapes recycling.
The “barrier”—a major hurdle!
It is evident that the main obstacle to truly recyclable paper and cardboard packaging is the issue of the barrier.
This challenge is well recognized by the industry, and countless innovation and R&D programs are underway to find alternatives to current systems based on plastic films and/or aluminum. And we can hope to soon see solutions that combine performance and safety with good recyclability.
This work is all the more meaningful given the significant progress being made in material forming processes, such as dry-molded pulp, which allows for intricate shapes while reducing water consumption—opening the door to numerous new applications such as bottles, closures, rigid refills, cushioning, and protective packaging, etc.
This work suggests that in the near future, we will see dry-molded cellulose pulp bottles and containers with shapes as intricate as those made from plastic or glass, with an appearance attractive enough to appeal to consumers on a large scale, and equipped with a barrier that does not disrupt recycling streams. Some initiatives are currently undergoing industrial and marketing testing, such as those by Carlsberg or certain Unilever brands, for example. For now, they are focusing on the bottle’s design and consumer acceptance, but are using plastic barriers while awaiting progress on barrier systems. A pragmatic, step-by-step approach. We can also commend, among other things, the work of the Pulp-In-Action consortium, which for the past four years has brought together brands, packaging suppliers, and public agencies with the stated goal of scaling up the use of paper, cardboard, and pulp for cosmetic packaging. Taking a pragmatic approach, the working group focuses on four particularly relevant packaging categories: semi-rigid refills, rigid refill cups, samples, and tubes. Each of these applications presents its own specific challenges, requiring not a universal solution, but a range of segmented technical solutions. Innovation in barrier systems is a key focus of this work.
The resource issue
As mentioned in the introduction, everyone wants wood for all sorts of applications, with packaging being only a small part of it. The construction industry is using more and more of it as a substitute for steel and concrete, which are themselves massive consumers of energy and emitters of greenhouse gases; the textile industry is increasingly using cellulose fibers derived from wood to replace synthetic fibers, which are one of the main sources of microplastics generated by fiber wear during washing; the energy sector is seeking to increase the proportion of “biomass” energy, using wood as a fuel as an alternative to fossil fuels, etc.
Once again, we see that, like all materials, wood presents its own challenges—and they are significant ones.
Alternative sources based on cellulose fibers are beginning to be utilized, such as straw, sugarcane, miscanthus, and hemp. These fibers also have the advantage of rapid growth, allowing for a shorter production cycle, and can adapt to regional conditions. Nevertheless, they are currently far from meeting demand.
Ultimately, this example illustrates a fundamental problem with modern consumption: we are living beyond the planet’s means and, overall, consuming too many resources; replacing one material with another without fundamentally changing the model solves nothing and merely shifts the problem. The idea of “responsible consumption” is a comfortable illusion that allows consumers to continue overconsuming with a clear conscience!
*Gérald Martines founded IN•SIGNES to provide companies in the beauty and luxury sector with a wealth of experience in innovation, sustainable development, and business development, gained from 30 years of experience in marketing, design, R&D, sales, and general management roles in several international groups that are leaders in the beauty and design industry.
With a master’s degree in physics, a degree in mechanical engineering, a postgraduate degree in materials science, an MBA, and a master’s degree in prospective studies, Gérald Martines has a 360° view of the various professions, skills, and functions that contribute to strategic thinking on innovation and sustainability.
