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Design and development of an innovative ecoefficient low-substrate flexible paper packaging from renewable resources to replace petroleum based barrier films

Final Report Summary - FLEXPAKRENEW (Design and development of an innovative ecoefficient low-substrate flexible paper packaging from renewable resources to replace petroleum based barrier films.)

The objective of FlexPakRenew was to develop innova tive flexible functional packaging solutions, using renewable resources to replace pet roleum-derived barrier films. The project focused on recyclable, biodegradable products, envi ronmentally friendly processes and was limited to the delivery of paper based multilayer b arrier material for flexible packaging. This project combined (i) upscaling of technologies /materials that were already proven at laboratory scale and (ii) the development of new ma terials/new technologies. All the developments were done with a special attention pai d to product life cycle and thorough sustainability assessment to prove environmental ec onomic and social performance and potential for up-scaling from laboratory scale to p ilot scale.

Upscaling of proven technologies

The core of this project was to develop a medium ba rrier material, applicable on paper, based on water borne coatings made from a plasticiz ed starch matrix reinforced with pigments. Starches were combined with several candi date bentonites and plasticizers in order to optimise the bentonite dispersion and mate rial interactions to maximise the barrier properties while getting some coating flexibility. Considerable effort has been invested in optimizing the colour rheology to match the paper c oating process requirements. During the project, the solids of the colour was raised from 1 0 to 20% while water vapour transmission rate was cut by 3.
A breakthrough green chemistry process, named chrom atogeny, that brings hydrophobicity to papers and boards, was developed at pilot scale. For the first time ever, it was proven that the combination of a reactive coating with chromato geny could work at pilot scale on a reel to reel process to produce materials having a perfect water repellence and very low water vapour transmission rate.

New materials/new technologies

During the project, it was proven that paper for fl exible packaging has to be designed to receive barrier coating. Very important properties, such as roughness of the substrate and air permeability, could be tuned thanks to the addition of MicroFibrillated Cellulose (MFC) at the wet end of a paper machine thanks to spray or curta in coating technology.
A great deal of work was dedicated to finding alter natives to starch, nanoclays and synthetic plasticizers in medium barrier coating. It was demo nstrated that the use of derived hemicelluloses, i.e. xylan from birch, could be a v ery good matrix combining the advantages of a good barrier material, hydrophobic, heat seala ble and being biosourced, not in competition with food industry. It was also demonst rated that starch nanoparticles, produced from starch granules could offer an organic, biodeg radable pigment that could replace nanoclays. Microencapsulation of biosourced oils in to biopolymers also showed a plasticizing effect on starch based layers and could offer an al ternative to oil-based plasticizers. Vacuum coating is a proven technology used to magni fy the barrier properties of plastic films. For the first time, it was shown that this very dem anding process in terms of substrate properties (stable when exposed to vacuum cycles an d roughness preferably lower than 50nm) could be adapted to a coated paper to deposit an inorganic layer and magnify the barrier properties. Successful research was undertaken to develop antim icrobial coatings that facilitate a prolonged shelf life for packed food products with releasing less quantities of preservatives on the food surface. In this way, the amount of dir ectly added preservative to the food and thus the consumer ́s exposure to preservatives can b e reduced. Both the use of preservatives in the bulk of a starch layer or embe dded in capsules were assessed to modulate the preservative delivery.
In the end, FlexPakRenew demonstrated at pilot scal e that a set of technologies can be combined to produce performing paper based packagin g materials with a demonstrated environmental gain. Some steps have however still t o be climbed to get the cost performance and come to industrial production scale.