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Innovative structured polysaccharides-based materials for recyclable and biodegradable flexible packaging

Periodic Reporting for period 3 - SHERPACK (Innovative structured polysaccharides-based materials for recyclable and biodegradable flexible packaging)

Reporting period: 2019-12-01 to 2020-11-30

The global flexible packaging market size was estimated at USD 222 billion in 2016, growing at a forecast CAGR of 4% in coming years. It is dominated by plastic materials. In addition, films and multilayer materials can be difficult to recycle. Today, key market drivers include cost and sustainability, and the demand for bioplastics and alternatives to plastics is growing.
SHERPACK aimed at developing an innovative high barrier, renewable, biodegradable and recyclable flexible paper‐based packaging material, in order to replace plastics or aluminium foil by an advanced biomaterial. The targeted market was flexible packaging materials for dry food, evaluated in Europe in 2020 at 1.6MT per year.
This new material relies on 3 major innovations developed from Technology Readiness Level 3 up to 5 during the project:
- Patented wet-lamination process used to add a thin layer of Microfibrillated Cellulose on the paper substrate to offer excellent barrier properties to grease, oxygen, and contaminants
- Formulation of a PolyLacticAcid-based waterborne emulsion using innovative mixing and stabilisation approaches, and coating on the substrate to provide heat sealability and water vapour barrier
- Specific design and application of a polysaccharide grid to improve stiffness and grip
The innovations are then assembled into 2 proofs-of-concept. PoC1 includes the MFC and biopolymer layers, while the grid is added to the PoC2. Finally, all the developments are driven by the constraints and requests of the packaging value chain, and assisted by a Life Cycle Analysis to prove their environmental benefit.
A consortium of 6 partners was set-up for achieving the objectives, with 3 research centers (CTP, ITENE, CNR-ISOF) and 3 industrial groups (Ahlstrom-Munksjö, Cargill, Borregaard). An advisory group of stakeholders was also involved to help define requirements and ensure relevance of the new material with the value chain.
At the end of SHERPACK, the main objectives were achieved and the 2 PoC were produced at lab scale, demonstrating the feasibility of combining the 3 technologies into one new material. The performances of the new materials are superb in terms of barrier to grease, oxygen, and contaminants, reaching levels that will enable entry in the food packaging market. The polysaccharide grid gave outstanding results for stiffness improvement, opening the door for weight reduction of such materials. Last but not least, the materials that were developed fully comply with food contact regulations in Europe, and are recyclable and biodegradable.
SHERPACK's 3 major innovations have been developed as planned.
MFC wet-lamination was optimised at lab scale. Material and process parameters were selected to reach excellent barrier performances to grease, oxygen, and contaminants with a 100% cellulosic material. Moreover, the process allows joining the paper and the MFC layer without using any glue.
For the formulation of the PLA-based emulsion, polymer selection and optimisation of emulsion process parameters allowed producing stable emulsions. The formulation was improved with the addition of selected biodegradable thickeners, providing suitable rheological properties. This innovative biopolymer emulsion process was patented. However, the heat sealability and water vapour barrier performances of the biopolymer layer did not reach expected targets. Alternative solutions were investigated and allowed to reach better performances.
Polysaccharides have been formulated and deposited on the substrate using a screen-printing process. The process was optimised in terms of formulation (modified starch was the best material to increase specific stiffness) and of grid pattern (a sinusoidal pattern shows a greater stiffness improvement). The bending performance of the grid printed material was tripled under optimal conditions, which lead to filing a new patent.
The 3 technologies were successfully assembled to produce the 2 PoC. The assembly of the different layers of the material went smoothly, thus offering excellent perspectives for future industrialisation. The performances of the PoC confirm separate findings on the 3 technologies: barrier performances to grease, oxygen, and contaminants are excellent, the improvement of the specific stiffness due to the grid is outstanding, and heat-sealability and water vapour barrier should be improved. Alternative solutions were preliminary tested and gave promising results for further development.
The PoC also have several end-of-life options: they are recyclable in a conventional paper stream and biodegradable, and are also suitable for energy recovery. In addition, their projected carbon footprint is quite close to that of their fossil-based counterpart.
The materials that have been developed in the SHERPACK project achieve many of the objectives that were set. SHERPACK demonstrated the viability of these innovative technologies at low TRL scale, and the next step will be to upscale them.
These results have been disseminated in several international conferences and 2 workshops during the project, and will generate several scientific articles that will be published in 2021.
Thanks to the 3 innovative technologies developed from TRL 3 to 5 in Sherpack, we are now closer to achieve a biobased, recyclable, biodegradable paper-based flexible packaging material.
The possibility to obtain a fully cellulosic barrier material showing better performances than most polymers used today, using an industrially viable process when upscaled, was demonstrated. This will help replace aluminium layers in future packaging materials.
A new emulsification process was developed for biopolymers, which can be used to obtain stable biopolymer emulsions that can then be coated onto cellulosic substrate. The PLA-based emulsion complies with EU food contact regulations, a status that, as far as the Consortium is aware, no other biopolymer emulsion can claim. Further optimisation of this emulsion may yield the possibility to replace current solutions used for water vapour barrier and sealability by a biobased alternative.
The reinforcement polysaccharide grid developed during the project has shown outstanding performances in improving the specific stiffness of the substrate, thus opening the door for a significant reduction of weight of packaging materials. This highly innovative concept had never been implemented on paper before Sherpack, and will contribute to the societal need of reducing the use of resources.
The trend in replacing fossil-based packaging materials by biobased materials has grown significantly, and the value chain as a whole is now involved in the developments of plastics-free packaging materials answering the push from EU towards a circular economy.
The achievements of SHERPACK in that regard are significant: the PoC developed within the project have demonstrated that obtaining a 100% recyclable cellulosic material with excellent barrier performances is possible, that replacing fossil based packaging materials is feasible. There is a need for continuing research and starting upscaling activities on these new technologies.
Finally, SHERPACK strongly contributed to the development of the bio and circular economy in Europe, by developing biobased and recyclable materials that will in the future reduce the share of fossil-based materials on the market, and increase the rate of packaging materials recycled in a paper stream.
Structure of the 2 proofs-of-concept
SEM pictures of the coated biopolymer emulsion
Value chain
Best performances achieved
Synthesis of the project
Reinforcement grid patterns used in the project
Main results of the LCA carried out on proof-of-concept 2
Layers of the developed materials
Partners logos
End-of-Life results for the proofs-of-concept
TRL scale of the project