Barrier Papers for High-Performance Packaging
Food packaging is multi-faceted – it must securely enclose products and have an attractive appearance. Furthermore, it will soon have to meet strict design-for-recycling criteria according to the PPWR (Product Packaging and Recycling Directive). Modern barrier papers can replace multilayer plastic packaging in many applications and can be disposed of as mono-materials in wastepaper recycling.
However, the high-performance machine processing of these papers is demanding. The paper manufacturer Sappi and the packaging machine manufacturer Sacmi Packaging & Chocolate are collaborating on product development to offer brand manufacturers innovative and sustainable packaging solutions.
What do KitKat bars, Nucao and Tony's Chocolonely chocolates, and Griesson pastries have in common? According to media reports, these branded products are packaged in barrier paper pouches. Such paper packaging still seems exotic, but that could soon change. After all, the PPWR (Product Packaging Reform Directive) requires a significant improvement in the recyclability of packaging by 2030. Problematic composite plastics must be replaced with more environmentally friendly materials, and barrier papers offer a highly efficient recycling loop as an alternative. These papers are classified as mono-materials and can be easily disposed of by consumers in the paper waste stream.
Challenge: machine compatibility
Modern barrier papers have the potential to replace plastic films. A thin dispersion varnish reliably protects food products from the ingress of moisture, oxygen and mineral oils, while conversely preventing grease and aromas from escaping the packaging. Depending on the application, they can also be heat-sealable. Brand manufacturers also benefit from the high-quality appearance of these easily printable papers and their pleasant feel. However, machine processing has proved challenging, as paper behaves differently than film. To withstand the mechanical stresses during the packaging process on fast, fully automated machines, it must be tear-resistant. Furthermore, the paper should fold precisely without breaking and requires a certain degree of stiffness for smooth processing.
Cooperation for Innovation
Sappi is a market leader in fibre-based flexible packaging papers. The increasing demand for barrier and high-barrier papers that are recyclable in the paper waste stream prompted the company to install a state-of-the-art barrier coating line at its Alfeld site in 2023. This high-tech investment increased capacity and also opened up new possibilities in product design. With the new line, Sappi is conducting intensive development work on barrier paper solutions, underscoring its decades-long commitment to such functional papers. "We believe that innovation can be accelerated through corporate collaborations. Therefore, in addition to our customers, we also wanted to involve a renowned packaging machinery manufacturer in the development process," explains Sibylle Hajostek, Market Manager Paper & Packaging Solutions at Sappi Europe.
The invitation from Sacmi Packaging & Chocolate to its research and development centre for primary and secondary packaging machinery in Neuhausen am Rheinfall, Switzerland, was therefore all the more welcome. Among other things, Sacmi engineers there focus on advanced materials.
Barrier papers have a great future in food packaging, especially in the premium segment. Therefore, they must be processed efficiently by our systems. This includes application know-how from packaging to quality control, fast and flexible format development, and material testing.
says Herbert Hahnenkamp, General Manager DACH at Sacmi
Test series and findings
The meeting in Neuhausen am Rheinfall in 2024 marked the beginning of a close collaboration between the two companies, which continues to function exceptionally well to this day, without the need for a formal contract. Sappi and Sacmi initially defined their goal as offering the food industry the same performance with paper packaging as with plastic. The partners first conducted a series of tests with samples of innovative barrier papers on flow-pack machines and wrapping machines. Subsequently, Sappi modified the base paper formula to improve its mechanical properties and achieve higher tear resistance. Sacmi, on the other hand, made adjustments to its flow-pack machines regarding tensile stress, sealing and forming.
"The forming shoulders are crucial here. For paper applications, we now rely on components that are individually custom-made using 3D printing," explains Herbert Hahnenkamp. Thanks to these insights, packaging lines originally designed for processing plastic films can now be converted more quickly and continue operating at the same performance level. And the knowledge gained is incorporated into product engineering.
Sappi has developed new high-barrier papers that can be optimally processed with its packaging machines. The Guard Pro OMH paper is designed for various applications, such as flow wraps, sachets, pillow bags and doypacks using cold sealing, while the Guard Pro OHS paper is also heat-sealable. These mono-material papers help brand owners achieve their sustainability goals without compromising on performance or production efficiency.
Success as an incentive
The interim assessment of the development partnership is therefore entirely positive. Sibylle Hajostek comments: “Our collaboration is characterized by mutual trust, and the initial successful projects are both confirmation and motivation. The barrier papers can be processed efficiently and reliably using Sacmi's fully automated systems. Synergies are also emerging in sales.”
The interim assessment of the development partnership is therefore entirely positive. Our collaboration is characterized by mutual trust, and the initial successful projects are both confirmation and motivation. The barrier papers can be processed efficiently and reliably using Sacmi's fully automated systems. Synergies are also emerging in sales.
comments Sibylle Hajostek
The partners advise the food industry not to postpone the introduction of environmentally friendly packaging solutions. After all, switching to barrier papers also requires shelf-life tests, which can last up to a year.
At the interpack trade fair, the fully automated processing of Sappi barrier papers on Sacmi's form-fill-seal machines will be demonstrated in Hall 4 (E05 and F05).