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Process developments for a recyclable and compostable all-cellulose multilayer material for packaging

Periodic Reporting for period 3 - CelluWiz (Process developments for a recyclable and compostable all-cellulose multilayer material for packaging)

Reporting period: 2021-12-01 to 2022-11-30

Packaging is necessary to transport and protect food and goods and communicate with the end-user. The food packaging industry has always been agile to follow consumer expectations and societal changes. This industry is nowadays under a great pressure from both authorities and consumers to improve its environmental and sustainability credentials in the coming years. So there is a need for the development of a new generation of packaging that has at least the same technical performances as today’s mono or multi-materials but with a demonstrated recyclability and biodegradability.
CelluWiz overall objective is to develop two processes able to produce an all-cellulose packaging material that can offer a competitive alternative to existing multi-layers plastic materials or multi-materials used in the packaging sector while being renewable recyclable/recycled in the paper waste value chain and biodegradable. These two innovative processes, the MFC wet lamination process and the chromatogeny process were combined to produce three proofs of concept: clamshells, cups and trays. The environmental benefits of the innovative processes and materials and their easy integration into the value chain, were assessed by performing Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) with accurate and relevant data.
CelluWiz has made it possible to develop the two technologies to produce at pilot scale all-cellulose packaging materials with great barrier properties for food packaging.
The laminated and chromatogeny-grafted cardboard reels produced at pilot scale made it possible to produce 3 proofs of concept (clamshells, cups and trays). Compostable, recyclable and biodegradable in the marine environment and in industrial compost, these products have excellent barrier properties.
This project paves the way for a new generation of 100% cellulose packaging materials as an alternative to existing plastic or complex materials.

At the end if the project, the following major scientific and technological achievements can be pointed out:
From WP2
• MFC wet laminated reels with targeted oil barrier were delivered for the subsequent WPs to produce the PoCs.
• Operating window of the small pilot machine in terms of the influence of MFC concentration, MFC grade, machine speed, feed rate, filtration media, vacuum boxes, replication and drying was determined and described.
• Homogeneity and dryness content before replication were slightly improved with replication on wet board and vacuum boxes with higher suction area respectively.
• The analysis of 3D images obtained with X-ray microtomography enabled the determination of the thickness of the MFC layers and its contact surface to the board.
• The analysis of the mechanical behaviour of MFC films under bi-axial tensile loadings proved that MFC films induce a pronounced driving stress to curl the wet laminated board upon drying.
From WP3
• A methodology to investigate the grafting in the z-direction has been implemented allowing the localization for grafted moieties
• Samples with ultra-high grafting densities has been obtained after having developed a new technology to open the MFC films.
• Grafting of MFC films at ultra-high grafting densities led to performances in terms of barrier to water well beyond the specifications targeted for all PoC
• A power law relationship between grafting densities and water barrier performances has been evidenced, allowing to predict targeted values of modification for a given required
• The chromatogeny process has been up-graded by adding steam boxes before and after the grafting that has significantly increased the grafting efficiency and the mechanical properties of the MFC laminated films
From WP4
• Coarse elements removal in an MFC suspension by screening through fine wire opening has been proven in device developed at lab scale.
• Deflocculation in an MFC suspension by screening in a semi-industrial size pressure screening pilot plant at up to 2,7% concentration has been repeated and shown stable
From WP5
• Steam box after grafting improves convertability due to higher moisture content
• The proof of concepts were produced tested and delivered according to plan
• Not all KPI for barrier performance were met, testing of the demonstrators in real life use however showed excellent to good performance

From WP6
• The 3 PoC are compatible with conventional industrial line for the recycling of packaging, therefore they accomplish the standard EN13430 “Requirements for packaging recoverable by material recycling”. The recycling rate are: 100% for the clamshell & the tray and 97% for the cup.
• The environmental performance of the CelluWiz cup, in a cradle to grave perspective, is improved respect to the paper/PE cup in all the impact categories, with a reduction ranging between 18 and 82%.
• A 3D eco-efficiency analysis shows that the CelluWiz cup is the most sustainable option compare with the paper/PE and the PS plastic cup analysed as benchmarks.
• In terms of suitability for food contact, the tested materials comply with the requirements applicable to paper and board according to Recommendation BfR XXXVI, although the intentionally added substances must be authorised for such use, even though no specific migration of these substances is detected under the conditions of use studied.
To reach Celluwiz overall objective, four specific objectives have been defined:
1-Develop the wet lamination process:
This process assembles, without glue any papers and boards with a MicroFibrillated Cellulose (MFC) layer thus creating a stratified cellulosic material. This MFC layer brings stiffness, lightweighting, barrier to air, grease and oxygen. At the end of the project, the MFC wet lamination pilot machine is able to produce up to 80kg per day of carton board wet laminated with a 20g/m² of MFC.
2-Develop the chromatogeny coating and grafting process for MFC layers:
This process is an ultrafast and efficient solvent free chemical grafting able to turn hydrophilic cellulosic materials into hydrophobic materials. The chromatogeny pilot is now able to treat 500Kg of wet laminated board per day. On standard wet laminated board, the grafting density is 35mg/m² compared to 19mg/m² at the beginning of the project. Based on the works developed to open the structure of MFC, 500mg/m² could be reach at pilot scale.
3-Produce 3 proofs of concept all-cellulose materials: Clamshells, Cups, and Trays:
100 pieces of each PoC were produced.
4-Demonstrate the environmental benefits of the innovative processes and materials and their easy integration into the value chain, by performing Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) with accurate and relevant data:
When comparing the CelluWiz Cup with the paper/PE cup being both recycled, CelluWiz Cup can reduced the carbon footprint by 40% and if we compare the CelluWiz Cup being recycled with the PS plastic cup incinerated, the reduction is 75%, therefore the KPI is achieved.
3 PoC
Cup PoC with water
CelluWiz targeted proofs of concept
CTP's chromatogeny pilot machine
Clamshell PoC with a burger
CTP's MFC wet lamination laboratory equipment
Trays PoC with chips
CelluWiz sample