Making the right decision when it comes to packaging material is a challenge for manufacturers. Factors such as product protection, machine runnability, environmental friendliness, cost-effectiveness and consumer expectations all need to be reconciled. A seemingly sustainable material may not necessarily be the most ecological solution. Packaging machine manufacturer Schubert has been building up comprehensive expertise for several years, which it intends to make increasingly available to its customers in the future.
In recent years, the image of packaging among consumers has been caught somewhere between poor recycling, littered oceans and global warming. Plastic especially has attracted harsh criticism because of microplastics in the environment. This is very noticeable at the point of sale and raises many questions for manufacturers of consumer goods such as food, cosmetics or confectionery. But the equation is not quite as simple as the fairy tale of evil plastic and good paper. It is difficult to communicate with end-customers in a way that they understand, while still meeting their wishes. And it can be even more challenging to master this change cost-effectively as a manufacturer.
A recent study* conducted by the GVM German Gesellschaft für Verpackungsmarktforschung (Engl.: Association for Packaging Market Research) shows that the industry has saved a considerable amount of material over the last three decades by using more lightweight packaging. In 2020, this amounted to some 1.6 million tonnes. However, the product market and consumer behaviour have changed so much that the total consumption of packaging has nevertheless increased. With the European Union’s Green Deal, the demand for less packaging is now being joined by the call for recyclability, by 2035 at the latest.
High recycling rate of cardboard
Cardboard has it easy in this context. In Germany, the recycling of paper and cardboard works very well: more than 90 per cent of the collected waste is reprocessed into paper products. Within the EU, the figure is above 70 per cent. This is another reason why the trend towards “cardboard instead of plastic” has already left its mark, for example with the increased use of trays, sleeves or other secondary packaging. The latest goal of the environmentally friendly transformation includes blister packaging and boxes that do not require any glue at all. Paper-based solutions, for example in the form of film, are also considered: if the foreign material content is not too high, the packaging ends up in the paper bin and is fed into the recycling system.
Several trends with plastic
In plastic packaging, market trends towards sustainability are also emerging. Many manufacturers are working with thinner materials for trays, bottles and films, increasing the recycled or biomass content in the packaging, and trying to establish refillable packaging and reusable systems. However, the problem and the reason for the negative image of plastic are inadequate recycling cycles and confusing labels – from biobased to biodegradable to compostable (see glossary!). What may appear ecologically sound at first glance can quickly turn into a waste disposal problem, depending on how it is disposed of and the recycling process itself. Even conscientious waste separation in German households does not guarantee that plastic packaging is actually recycled – there are still many gaps in the intended cycle.
Recycling – a science in itself
One of the underlying causes is the type of recycling used. Until now, waste management companies have been working with purely mechanical recycling processes. So, if waste from different plastics is fed into the same process, the result is often a lower-quality material that cannot be reprocessed into similar packaging. Composite materials such as films cannot be recycled and the only option is incineration. Packaging solutions made of mono-materials can help as they enable the entire packaging to be specifically fed into a recycling process, the result of which is a pure plastic granulate.
Even in paper recycling, all that glitters is not gold. The new paper-based materials behave very differently in the recycling processes. The paper is either laminated or coated to ensure the barrier or sealing properties required for product protection. When the paper fibres dissolved in water are sieved out, however, a large proportion of the fibres in laminated papers remain attached to the ultra-thin film. This results in high material losses and pushes the recycling rate down. Coated or water-coated papers, on the other hand, are much easier to separate from foreign material.
Expertise
The complex correlations between material properties, waste collection and recycling make it difficult for companies to make informed and economically sustainable decisions for or against a specific packaging material. And all the more so because even in the EU there are still major differences in waste disposal between countries. To find a good packaging solution, manufacturers would basically have to ask themselves in the case of each individual product and for which market it is intended, how consumers dispose of the packaging and what happens to it afterwards. There is also the important question of whether the packaging material and packaging design under consideration are also suitable for an automated packaging process. A challenging task for a manufacturing company, but one that can be solved in close coordination with packaging material producers and automation experts.
With all this in mind, Schubert has been consistently expanding its expertise in the field of materials for several years. Laura Gascho, plastics engineer in the application technology department at Gerhard Schubert GmbH, explains: “We want to support our customers in the choice of materials just as much as in the design of a packaging machine. A wide variety of packaging materials are collected at Schubert and tested in the Schubert Technikum (technical centre) for their machine-suitable properties. If required, the materials can also be examined in detail in the in-house laboratory. “Our laboratory testing includes physical and chemical analyses, friction value measurements, tensile tests and much more. We verify material structure with ultra-fine cross-sections under a digital microscope,” Laura Gascho reports. “Next, we create an analysis device to be able to precisely determine the types of plastic and their proportion in a given material.” This enables the machine manufacturer to show customers samples from its pool of marketable materials and provide them with comprehensive, independent advice on their selection. This also includes the development of alternative packaging made of cardboard. “With every project we complete, our knowledge base increases to the benefit of our customers,” says Laura Gascho.
Testing for machine runnability: no real solution without the right partner
Expert partners in the field of packaging materials and packaging printing are indispensable for building up the material pool. Schubert has been working with many material manufacturers and packaging producers for some time now and is committed to further developing these partnerships. Testing possibilities in the Schubert Technikum directly on a packaging machine are not only beneficial for customers, but also for the material developers. “Here we can try out entirely new solutions, such as paper pulp, and test them in detail,” Laura Gascho highlights. “The partnerships are very important for us and we learn a lot from each other.”
At Schubert, machine runnability has priority, because material recyclability is already determined by the respective manufacturer. In the case of flowpacks, the Schubert experts test sealability, tear strength and packaging size changes. Initially, this is carried out using Schubert technologies which are already available. But if required, new components such as robotic tools or a forming shoulder can be specially developed to create a flowpack. “Sealing mono-materials or paper-based films is not always easy. There is a lot to be considered,” Laura Gascho points out. “For instance, paper thickness, coating, printing and especially, sealing times. Paper needs either a lot of time or a lot of heat during the sealing process. Mono-materials are even more sensitive, as they burn very easily.” This is why Schubert uses special forming shoulders and ultrasound sealing technology in its Flowpackers. This protects the material and the product, reducing the number of rejects in the packaging process.
In the area of cardboard packaging, in addition to the material itself, the shape of the blank plays a major role in the feeding into the packaging machine, as in the erection and closing of the box. Small changes can under certain circumstances increase material efficiency, make the packaging process more stable or even simplify the entire machine concept.
Mono-materials for complete recycling loops
With sustainability being such a hot topic, packaging expert Laura Gascho points out a key aspect to be considered: “At Schubert, we are not always in favour of eliminating plastic at the expense of durability. A product’s CO2 footprint is primarily created during the production and processing of raw materials. Packaging accounts for a mere fraction of this. And it ensures that sensitive foodstuffs survive transport undamaged and remain fresh for longer once purchased. Without packaging, the ecological damage would be far greater.” With this in mind, it is all the more important for Schubert to be able to offer its customers truly sustainable solutions in terms of recycling cycles. “Mono-materials are the most important trend for us. With them, complete recycling cycles can be established, both for paper and for plastics,” Laura Gascho firmly believes. If plastics were separated by type and completely recycled, hardly any new plastics would have to be produced from fossil raw materials and no more microplastics would enter the environment. At the same time, the key barrier functions developed to ensure the shelf life of foodstuffs could continue to be used without hesitation. Certainly, a goal worth pursuing, with a long way to go. This is precisely why the Schubert family business will support its customers in choosing more ecological packaging in the future, in line with its Mission Blue sustainability strategy.
* “Development of consumer behaviour, volume and material efficiency of packaging”, Gesellschaft für Verpackungsmarktforschung GVM, May 2022
Environmentally friendly plastics
The environmental friendliness of plastic packaging is promoted with many different terms. But what does it all really mean?
Bio-based:
Bio-based materials consist, to varying degrees, of renewable raw materials such as bamboo, maize starch or grass. To use them for packaging, they need to be shredded and mixed with additives.
Pro: No fossil raw materials such as petroleum are used.
Con: Not every bio-based material is biodegradable or compostable. So, under some circumstances, the result is packaging that is not recyclable.
Biodegradable:
Biodegradable materials can be broken down into their constituent parts by microorganisms over a shorter or longer timeframe. This also includes certain plastics.
Pro: If the materials end up in the environment due to incorrect waste disposal, they simply decompose and no microplastics are produced.
Con: The decomposition process can take a very long time, in some cases several years.
Compostable:
Compostable materials are biodegradable substances that can be decomposed into their constituent parts within defined timeframes and temperatures. A distinction is made between “industrially compostable” and “garden compostable”. Industrial composting plants work with shorter timeframes and higher temperatures.
Pro: Compostable materials degrade more quickly than biodegradable variants.
Cons: Recyclability requires ultra-modern industrial plants, which are seldom in use to date. In conventional plants, materials need to be painstakingly sorted out and incinerated. Plastics often end up in garden compost, which remain in the environment much longer than intended because composting conditions are not ideal either.
