Packaging materials: How sustainable are they in comparison?

Image: Unsplash / Clair

Packaging is an integral part of our everyday life because it fulfills important tasks: it guarantees the quality and shelf life of food and ensures that the products are protected during transport.
Packaging is also an important information and advertising medium. But in view of the ever-increasing environmental catastrophe caused by packaging waste, the search for ecologically justifiable alternatives is great. What materials are there and what impact do they each have on the environment?

conventional plastics

After China, Europe is the largest plastics producer and Germany has by far the highest demand in Europe. The greatest demand is for polypropylene (PP) and polyethylene (PE), which are used particularly often for food packaging due to their properties. Polypropylene, polyethylene, PET or expanded polystyrene are the most commonly used plastics in the packaging sector.

Plastic packaging only uses around two percent of the oil produced. Despite being carbon-based, plastics decompose extremely slowly over hundreds of years, especially in low-oxygen landfills. Most plastics ever produced still exist in some form in the world, contaminating soil and water. The effects of microplastics on the human organism have not yet been fully researched, but it is suspected that plastics may have negative effects on hormone metabolism, among other things.

It is currently still very difficult for industry to do without plastics because they are light, thermally malleable and very resistant. Their effect on the environment is highly dependent on their recyclability and national waste systems. Overall, however, the effects of microplastics in the environment are threatening to humans, animals and ecosystems.

Image: Unsplash / Well Bertholt-Jensen

Degradable Plastics

Conventional plastics that are usually mixed with starch or other bioplastics or combined with chemical additives to accelerate decomposition are referred to as degradable. These plastics break down into small pieces too small to detect, but are not converted into biomass or biogas.

Biodegradable plastics

Biodegradable plastics are plant-based bioplastics that can be converted into biomass and biogas by microorganisms. Not all bioplastics degrade in time to be suitable for composting. Other plant-based plastics, typically made from sugar cane ethanol, could even be called non-biodegradable because they are basically the same chemical as fossil plastics. Arguably they are biodegradable, but the process can take hundreds of years.

Biodegradable plastic can still bring advantages. The pollution of the seas with conventional plastic is dramatic because it breaks into small pieces, releasing toxins and can be ingested by marine animals. Most bioplastics, on the other hand, dissolve in water within a few months. Nevertheless, environmental organizations warn against excessive promotion of bioplastics. It is misleading because consumers often assume that plastics will degrade in a few days.

Bio-based plastics are usually made from starchy and cellulose-rich plants such as corn, but sometimes also from oilseeds or wood. Biodegradable can from thermoplastic starch, cellulose, degradable polyesters and polylactide (PLA). PLA is a polymer made from lactic acid, which is obtained from starch and cellulose. PLA is one of the best-known bioplastics that are becoming increasingly popular on the market. In terms of its nature, PLA can hardly be distinguished from conventional plastic, but it has the disadvantage that it is not very heat-resistant and is therefore not suitable for hot food.

The problem with bioplastics

There are three categories of conditions under which bioplastics can degrade. The decomposition can be favored by water, oxygen or light. However, too many bioplastics currently end up in landfills where they are not exposed to optimal conditions for decomposition. In contrast to conventional plastic, they can then release climate-damaging methane gas there.

Compared to conventional production based on fossil raw materials, bioplastics are advertised as being more carbon dioxide-saving. But if you take into account the emissions from production, fertilization, harvesting and irrigation, the CO₂ savings can be minimal. Land used to grow food also has to give way to grow raw materials for the production of biogas and plastics. Extreme water consumption for irrigating the fields and the use of intensive fertilizers also contribute to the destruction of the environment. In addition, bioplastics can often only be composted in industrial composting plants with the addition of heat and water. But even these are not yet adjusted to the new bioplastics. Bioplastics are also problematic in connection with recycling. Since they are too similar to conventional plastics, they are confused and contaminate the recyclable materials, which extremely reduces the quality of the recyclables. At the current stage of development, bioplastics cause more problems than they solve and are therefore not classified as sustainable.

Image: Unsplash / The Tampa Bay Estuary Program

Bioplastics from algae extracts

Materials researchers around the world are experimenting with biological plastic alternatives made from algae extracts. For example, the agar obtained from red algae, known as a vegetarian substitute for gelatine, can be used to produce a kind of natural “plastic”. The material is lightweight, can be compressed into a solid, sheet-like form, or frozen into a cushion-like structure. Such new eco-friendly biomaterials are intended, among other things, to replace conventional fossil-based plastic coatings used in grease-resistant packaging. Grease-resistant paper, for example for take-away packaging, is usually coated with plastic and other environmentally harmful chemicals such as polyfluoroalkyl substances (PFAS). The new prototype coatings made from algae meet the functional requirements of conventional grease-resistant packaging materials well and at the same time represent a circular ecological solution because they are 100 percent biodegradable. In addition, these purely bio-based materials do not harm any marine life should it enter the water. Most of the projects and prototypes are not yet ready for the market or cannot yet be produced in the required quantities, but give great hope for the future.

Paper, Cardboard & Cardboard

Paper is a sustainable material when it comes from the right source. In their different strengths, paper, cardboard and cardboard are versatile and inexpensive materials. It is also biodegradable and compostable, but the proportion of paper mixed with plant composting should not exceed ten percent. Some printing inks or coatings often make paper unsuitable for composting anyway. However, paper is easily recyclable. Paper's formability tends to be underexploited as complex folds are more time consuming and difficult to machine. On the other hand, the material is excellent for printing.

The wood for the production mostly comes from managed pine forests. Globally, 90 percent of the pulp is made from wood. However, it can also be made from other fibres, such as sugar cane fibres, palm fibres, bamboo, hemp, flax, wheat and rice straw or reed. In the case of wood, a distinction can be made between mechanical pulp and pulp. Wood pulping is a purely mechanical process of splitting the material through a grinding process. Chemical pulp processing is more efficient, although the yield of the material is higher with groundwood. It is 90 percent due to the preservation of the lignin in the wood, which is removed during chemical processing. With chemical processing, the yield is only 50 percent. Cardboard or cardboard packaging is often seen as more sustainable, but unsustainable practices in the manufacture of paper products are not uncommon. Paper production uses a lot of energy and can be polluting. The production needs a lot of fresh water, which is mixed with chlorine for bleaching. Other substances are often added for the coating. Forestry to produce wood as a raw material can also pose a threat to biodiversity. Cardboard and paper can be recycled up to eight times before the fibers become too short to form a solid structure. The reuse of the recycled material ensures 28 - 70 percent less energy consumption in production than when manufacturing with fresh materials.

After cleaning the ink and glue, the manufacturing process is identical to that of new material. A little fresh material usually has to be added to get a sufficiently solid structure. Paper pulp with a high recycled content is not always suitable for food packaging as pulp from mixed sources can be contaminated by other materials and substances. Cardboard can also be heavier when recycled.

grass paper

A particularly sustainable alternative to conventional paper made from wood has been on the market for a number of years. A paper manufacturer from Hennef near Hanover set itself the goal of developing a more environmentally friendly alternative to conventional cellulose. The result is »Graspap« , a granulate made up of 100 percent grass or hay. Grass is available everywhere in large quantities and is one of the fast-growing raw materials. The production of the grass pellets requires the use of significantly fewer energy resources than conventional raw materials in the paper industry. The process only involves purely mechanical processing and pressing into pellets, which can be used directly for papermaking. With "Graspap" a complete renunciation of chemicals is achieved and it requires a greatly reduced use of water during the production process. The yield in the grass sifting process is almost 100 percent. The raw material grass is also very cheap and can be produced regionally anywhere. According to the manufacturer, cardboard made from grass paper can compete with conventional paper in terms of performance.

Pressed recycled pulp

Pressed cardboard made from recycled paper is typical for egg cartons. It contains a high percentage of recycled paper and can be recycled again along with paper and cardboard. Due to the high proportion of waste paper, they are perceived as particularly ecological, but the molding process requires a great deal of energy and water. The reprocessing of the recycled paper also requires a lot of energy, water and chemicals.

wood pulp

Groundwood is similar in appearance to recycled pulp and is commonly used for fruit and vegetable trays. The material is produced purely mechanically by grinding coniferous wood, mostly spruce. The wood is pressed against grinding stones with the addition of water and very finely divided. Groundwood is a very cheap fibrous material which, in addition to the cellulose fibres, contains all the non-fibrous components of the wood, such as e.g. As lignin and resin contains. It has short fibers and is therefore rather brittle, hard and somewhat yellowish despite bleaching. The field of application of this substance is therefore rather limited. Since groundwood is a purely natural product, it is also completely biodegradable.

Wood

Today, wood has largely been replaced by other materials, but is sometimes used in fruit and vegetable packaging or for cheese products and dried fruit. It suggests quality and, as a natural material, represents sustainability, which, like paper, depends on the source. Wood is durable, stable and moisture resistant, but expensive compared to other materials. Scraped from the trunk in a thin layer, it is relatively brittle and not very flexible, but can be steam pressed into shape to some extent.

Due to the natural material as well as the solid structure, it can be reused better than other materials in the home. It can be recycled in the form of chipboard. Since there is very little wooden packaging on the market, it is usually not collected separately in the household but disposed of as residual waste. While wood is biodegradable, it is not compostable in a realistic timeframe.

bagasse

Bagasse is made from sugar cane fiber, which is a by-product left after the juice is squeezed from the canes. The fiber residues are mixed with water and processed into a pulp, usually without the addition of chemicals, which is finally pressed into shape and dried. The resulting material resembles a very tear-resistant paper. For bagasse production, no additional area is currently used for the cultivation of raw materials, on the contrary, a waste product is sensibly reused. Bagasse is also heat-resistant and therefore suitable for both hot dishes and the microwave. The material also decomposes faster than bioplastics in the compost and can be disposed of in the organic waste bin. However, bagasse is quite unstable, so that some products are mixed with other substances to stabilize them, which in turn is detrimental to composting. When buying bagasse, it is therefore essential to use untreated products, which are actually a good, environmentally friendly alternative.

Image: Arekapak GmbH

palm leaf

The areca palm, or betel nut palm, has been cultivated in large parts of India, Southeast Asia and Africa for thousands of years because of its fruit, the betel nut. The palm leaf, actually a protective covering at the end of the palm frond, is an agricultural by-product. The renewable raw material accumulates in large quantities as leaves when the palm trees are cultivated. The cultivation of the areca palm in India extends over 400,000 hectares. Around 5.4 billion palm leaves fall from the trees that accumulate in the plantations each year. A large part of the existing raw material is unused and is burned as agricultural waste or rots in the cultivation areas.

A growing industry consisting of mainly small production units for the further processing of waste material has been established in India for several years. The palm leaf offers great potential due to its natural properties. It can be pressed into shape without chemical additives, using little water and energy. The material is mainly used to make disposable tableware such as plates and bowls for catering or private use. For this, the palm trees do not have to be cleared, nor do new plantations have to be cultivated to extract raw materials. After collecting, the leaves are washed and dried in the sun. They are finally pressed into shape under heat and pressure. After pressing, they are very stable and keep their shape. The product is 100 percent natural, biodegradable and fully compostable within three months. When dried, the palm leaves have a wood-like, light beige to brown color, sometimes with darker grains. The material is odorless and tasteless and has a natural moisture-resistant top that can even hold liquids for up to 24 hours. Palm leaf products are also safe for use in the refrigerator and limited use in the microwave or oven. Here you can find out more about which products palm leaf is suitable for and what you should pay attention to when using the material.

Due to other needs in India, the design and functional potential of the material has not yet been exhausted. Arekapak's goal is to develop new designs and areas of application and thus offer more sustainable, attractive and functional alternatives to conventional packaging. Explore our range of products or learn more about our custom design services .

Sources:

Boylston, Scott. Designing sustainable packaging.
London 2009: Laurence King Publishing Limited
Miller, Laurel; Aldridge, Stephen. Why Shrink-Wrap a Cucumber?
London 2012: Laurence King Publishing Limited
http://www.graspapier.de
https://algaeplanet.com/
http://www. Verbraucherzentrale.nrw/plastic packaging
https://www.plastikalternative.de/
https://www.bund.net/themen/chemie/achtung-plastik/