Canadian materials science company, Cellulotech claims to have developed a food contact-approved process that makes paper products resistant to water, grease, oxygen, and vapour – all while having no effect on recycling and composability.
In an interview with Packaging Europe, founder and CEO, Romain Metivet explained “Chromatogeny is a green chemistry reaction that grafts long-chain fatty acids on different substrates such as paper, starch, PVOH, minerals, etcetera to make them superhydrophobic while preserving their repulpability and compostability properties.
“Besides the strong and lasting barriers and its environmental advantages, the process is extremely cost-competitive. We use as little as 2mg of a reagent per square meter of specific surface area. 20mg are then needed for a substrate with 10 square meters of specific surface area per geometric square meter. One kilogram of such reagent costs less than €10, so the input cost per square meter ends up being less than 0.02 cents. It’s difficult to find anything more competitive.”
The process does not add a layer of a different material upon the surface of a substrate, instead it generates permanent ester bonds onto its whole specific surface area. Different from composites, Chromatogeny-treated products are monomaterials, thus they cannot be altered by plying or cutting. With contact angles well above the 90° mark any capillary uptake is inhibited. Thanks to these ester bonds, paper that was treated two decades ago still shows the same properties today as then.
Metivet believes that “Chromatogeny not only has the potential to solve a lot of issues faced by the packaging industry in terms of costs and sustainability, but also to expand the use of paper for other industries”.
The process for making paper hydrophobic using long-chain fatty acids has been known for over a hundred years, but it involved a solvent, complicated conditions, and was time consuming.
“Twenty-five years ago, Daniel Samain, now Cellulotech’s chief scientist, discovered a new solvent-free green chemistry process that was able to do this much faster and named it chromatogeny. (…) However, it was maybe too early, and the first pilot that was developed more than a decade ago came short in terms of speed and efficiency which, in our opinion, has limited the adoption of this technology, until now” said Metivet.
“Two years ago, Cellulotech was founded to start from a blank page and develop a scalable process. Instead of taking a traditional paper or printing engineering approach, we took a chemical engineering one. The new process we have developed brings the reaction time from a few seconds to just 0.1 seconds. As our grafting yield also increases, we can use fewer amounts of reagent and solve other issues that have been encountered in the past. Moreover, we are not limited by a roll-to-roll approach and can also treat whole corrugated cardboard sheets and some 3D shapes” he added.
The new process has been patented and industrial pilot plans with several partners in order to demonstrate the scalability of this solution are being finalized.
According to Metivet, “Applications are extremely diverse since this chemistry can offer a large range of barriers and strengths which offers us the ability to optimize the performance/cost ratio.”
Cellulotech is already approved for food contact in some jurisdictions and grafted PVOH could replace PE coatings in single-use food packaging such as paper cups, as well as eliminate PFAS. For other industries, it could replace plastic wraps on paper products or other packaging; grafted cardboard for frozen foods could be a potential market.
The ability to make corrugated cardboard “superhydrophobic” could help save some pulp but also get rid of things like paraffin for demanding applications, making this great material in construction or manufacturing.
Metivet adds that “beyond packaging, since grafted paper behaves like a “gore-tex”, we have shown it can be used to make 100% paper face masks or offer selective oil absorption for oil spill removal for example. We also investigate applications with textile and wood. It’s a whole new world of bioproducts that is opening in front of us and that is very exciting.”
The company claims that because of the minimal amount of reagent used in the process, any substrate that is initially repulpable and compostable will remain repulpable and compostable post-grafting in the existing waste streams, without posing any threat to the environment.
As of now, the company is focusing on finalizing partnerships and financing their pilot. Meanwhile, they will keep working on product development projects regarding new substrates and applications.
“Once the pilot is ready and running at 500 meters per minute or more, scalability will be demonstrated and we will be able to start producing niche bioproducts, run larger tests and start licensing this technology. We expect our machines to be commercially available within two to three years.” finalized Metivet.
