Who likes to buy a pig in a poke - or the contents of a bag without being able to see them? For many products, it makes sense to include a window in the packaging. What sounds simple in theory turns out to be more complicated in practice: A compostable paper bag, for example, is robbed of precisely this property with a plastic window. Are there solutions here that are also beneficial to our environment? 

Paper or plastic - that is the question here!

How simple the subject of packaging could be if everything could be put into paper bags - and sold! The bags could simply be added to the waste paper and then make their way through another processing cycle. However, paper has different material properties than plastic. For example, it is not waterproof or greaseproof, nor is it transparent.

As consumers, however, we have certain demands; we want to see exactly what we are buying. But that is only one side of the coin, because there are also certain requirements in retail itself. For example, if we fill the bags with rolls on our own, the staff at the checkout must still be able to take a look.

There are many other occasions when bags with windows are the perfect solution - after all, the eye eats with you

There is a reason why the visual appearance plays an important role in the marketing of a wide variety of goods. Even paper bags are enormously upgraded in this way, not to mention bags made of plastic or composite films.

However, the question of environmental compatibility is becoming increasingly important. The statements that these bags with windows are even compostable and therefore harmless to the environment from the consumer's point of view are often enough misleading about the fact that industrial composting must be involved. This would also be a way - certainly not the optimal one, but at least one that does not let the mountains of waste continue to grow. But that's the theory, because practice looks quite different.

Industrial composting - how does it work exactly?

So let's assume that the bags with windows are industrially compostable, disposed of separately and sent for composting. Then special facilities await the waste, where biogenic materials are converted into compost through a controlled, aerobic and exothermic biodegradation process. Sounds complicated? It is, because thermophilic phases above 55 °C must also be ensured to achieve the desired result.

In contrast to classic garden compost, it is precisely these external conditions that are stable in industrial composting. Nevertheless, it takes time until the bag with windows becomes garden compost:

• The DIN EN 13432 stipulates that packaging products certified as compostable must be degraded within a period of 22 days within a period of 22 days.
• PLA, i.e. Polylactide or polylactic acidswhich are synthetic polymers obtained from corn, for example, apparently degrade particularly well in industrial plants - good results were achieved here after just 11 days.

The European Bioplastics e.V. in turn assumes that compostable plastics must have decomposed within a period of 12 weeks , after 6 months they should have completely biodegraded.

This means that at least 90 percent of the material has been converted into carbon dioxide. The remainder must no longer contain any plastic.

As you can see, there are no uniform regulations. And: Both energy and time are required to break down the plastic into its components - it is thus withdrawn from recycling. Logically, this raises the question of whether this is the right way to go, because the plastic also has to be manufactured again for new packaging material, consuming new resources. True recycling management works differently.

Problem of understanding: recycling - how much plastic waste is recycled?

What do you expect when people talk about plastic recycling? Exactly, that's what our fellow human beings also think: That plastic is processed in such a way that it can be used to manufacture new products, thus reducing the need for new raw materials. To do this, we separate the waste, sort it and dispose of it via the existing channels. But what happens then?

The Federal Environment Agency, based in Dessau, Germany, provides information on this: the collected plastic waste is almost completely recycled. Accordingly, the picture for 2019 is as follows for 6.28 million tons of relevant waste:

• 46.6 percent - 2.93 million metric tons - were recycled for raw and mechanical materials
• 52.8 percent - 3.31 million metric tons - were used for energy recovery, i.e. incinerated and thus used to generate heat and/or electricity.
• 0.6 percent - 40,000 metric tons - ended up in landfills

Material vs. feedstock recycling

According to the Federal Environment Agency, mechanical recycling means that processes are used that do not significantly change the structure of the plastic and thus the material. Raw material recycling works in a completely different way: Here, the plastic is broken down into its basic building blocks with the help of chemical processes. In the best case, these building blocks can then be further processed.

Viewed positively, the incinerated plastic waste replaces other energy sources - but this would be a very broad interpretation of recycling. The assessment of the Federal Environment Agency, which is urging an expansion of raw and mechanical recycling, is correspondingly critical. This is the only way to reduce the use of new plastics, which in turn would have to be produced from crude oil or other resources.

"Real recycling" - why do we take so little advantage of this opportunity?

What do you think about recyclable packaging? Surely, like many other consumers, you assume that waste is recycled back into a material cycle. Theoretically, this is true. But in practice, it's not that simple: as soon as packaging is made of different types of plastic, it can't be recycled without a lot of effort. And that is too high for most protagonists.

This explains why the rate of genuine recycling has only hovered between five and seven percent - and this has been the case since the introduction of the Green Dot system, which was financed by the population.

Where is the plastic waste? This question was investigated in a documentary by ARD entitled "Die Recyclinglüge" ("The recycling lie"). The results were frustrating, because it is not landfills within the European Union that are frequented, but also on other continents. And the heating furnaces are loaded in various companies, such as a cement factory in Thuringia.

The perfidious thing is that the company not only receives free delivery of the heating material, but also money for accepting the shredded waste - from the disposal company.

Plastics: So why do we actually sort our trash?

This question is quite justified, because the bad reputation with which plastic packaging has to contend is not rooted in the material, but in our handling of it. In addition, it must be taken into account that

Not all plastics are the same - after all, there are more than 200 types, each with its own specific properties. You are probably familiar with the best-known ones:

• PE - Polyethylene
• PP - Polypropylene
• PET - Polyethylene terephthalate
• PVC - Polyvinyl chloride

Interesting and in high demand are plastics that are easy to recycle and from which, for example, reusable packaging can be made or which can be completely recycled. This is precisely what we focus on in the production of bags with windows: we consistently use plastic to facilitate recycling.

It is not without reason that plastic has become one of the most widely used packaging materials in just a few decades - it is the special properties and the interesting cost-benefit ratio.

The search for more environmentally friendly alternatives is well founded, but the paths taken are not always logical. While paper and cardboard can certainly offer an adequate substitute in certain areas, there are also areas where the material properties are not sufficient.

Even with glass, it is not always clear whether it can be a real alternative. The decisive factors are, after all, not only the manufacturing process but also other aspects such as the possibility of reuse and, of course, the capabilities of the material in question to also protect the goods in the way that is necessary.

Sorting plastic waste therefore makes sense, but the routes back into the material cycles would then also have to be created. There are also exciting approaches for composite materials here, but often enough they are only used as isolated solutions by companies.

Conclusion: Bags with windows - exciting potential for sensible recycling

Plastic bags that cover the oceans, disfigure entire stretches of land and become a danger to life for living creatures - we all have these images in mind when we discuss plastic.

However, this is only one side of the coin, which we as mankind have also caused ourselves. The other side shows a more positive picture, because plastic packaging such as our bags with windows have a low weight, consist of correspondingly little material and still protect the contents optimally. What's more, technically speaking, this plastic can be completely recycled - and recycled properly.

Ultimately, it comes back to the question: How do we as a society deal with plastic waste? Is the label that the packaging is (theoretically) recyclable really enough to ease our conscience?

There is still enormous potential lying dormant here, which we should exploit for the benefit of our environment. Products made from recycled materials are a first step toward a consistent circular economy, which should be our common goal. And at this point we are all called upon, every single consumer.