High-performance, all-cellulose food packaging that is good for the environment
Food packaging is intended to enable safe and efficient food transport throughout the supply chain while preserving the shelf-life of perishable items in stores and homes. Unfortunately, the properties that make packaging materials effective are the same ones that make them difficult to recycle. Conventional food packaging is made of multiple layers of different materials including foil, paper and plastics that are difficult to separate. Consequently, most containers end up in landfills or are incinerated. The CelluWiz project received funding from the Bio-based Industries Joint Undertaking, a public-private partnership between the EU and industry, to develop technologies enabling the production of all-cellulose packaging products that are compostable/biodegradable and recyclable.
Wet lamination of microfibrillated cellulose: barring grease and oxygen admission
Cellulose is the key component of plant cell walls and the most abundant polymer on Earth. Although cellulose is not a barrier to grease, oxygen, water and water vapour, its cellulose microfibrils perform well against grease and oxygen. Microfibrillated cellulose (MFC), a type of nanocellulose, is obtained by pre-treating cellulose fibres – enzymatically in CelluWiz’s case – followed by mechanical processing. MFC layers were applied to paper board using CelluWiz’s MFC wet lamination process, one of the two key technologies developed by the project. “Wet lamination is our unique patented process enabling a thin layer of MFC to be applied to paper or board without glue and resulting in excellent barrier properties to grease and oxygen. With CelluWiz, we advanced its technology readiness level and produced high-performing MFC wet-laminated board reels for the first time,” states project coordinator Philippe Martinez of the Pulp and Paper Research & Technical Centre.
Chromatogeny adds moisture resistance
The second key outcome of CelluWiz was advancing the technology readiness level of chromatogeny, a green, solvent-free technology used to impart hydrophobicity to cellulose-based materials. “CelluWiz enabled us to optimise the chromatogeny grafting process, reaching high grafting densities of the MFC layer at both the lab and pilot scale. We increased the grafted hydrophobic fatty acid content of MFC wet-laminated board by 80 %,” notes Martinez. CelluWiz’s pilots produced 80 kg/day of packaging materials compared to the original target of 1-10 kg/day and with higher grafting densities than planned. The all-cellulose materials are recyclable (EN 13430:2004), compostable (EN 13432:2000) and biodegradable in marine conditions (ISO 14852:1999 and ASTM D6691:2017) and were used to produce 100 pieces each of three products: clamshells, cups and trays. “Celluwiz combined wet lamination and chromatogeny grafting of MFC to produce all-cellulose packaging with good barrier properties to grease, oxygen, water and water vapour without the use of glue or plastic,” Martinez summarises. He estimates that the materials and processes can reduce the carbon footprint up to 40 % when substituting recyclable fossil fuel-based materials and by 75 % compared with non-recyclable products. CelluWiz outcomes could revolutionise packaging with outsized benefits for the environment.
Keywords
CelluWiz, cellulose, packaging, MFC, wet lamination, chromatogeny, paper, microfibrillated cellulose, food containers, nanocellulose
