At the time of writing, January 2021, we have for almost a year in connection with the pandemic seen examples of how important the material group plastics is for our society in the form of products for treatment and protection in health and care. At the same time, the focus in the debate on the use of plastics is mostly focused on the problems that plastics cause in the form of littering of our environment and consumption of fossil raw materials.
About 6% of the world’s annual oil consumption is used for plastic production. A number of restrictive measures are now being implemented by the authorities around the world, such as a ban on disposable cutlery and straws in plastic and excise duties on plastic bags.
The plastics industry has long worked to find solutions to reduce the consumption of fossil raw materials and an interesting track is “bioplastics”. But despite many and long efforts, only about 1% of the world’s plastic production of 370 million tonnes is attributable to this material group. Obstacles on the road have been and still are of both a technical and cost nature.
This article aims to provide a brief overview of the current situation for bio-based plastics.
The seemingly simple term ‘bioplastic’ is often used too broadly and should be replaced by more well – defined terms.
The interst organization European Bioplastics defines bioplastic as a plastic material that is either bio-based, biodegradable or both. To reduce the risk of confusion, the following terms are appropriate to use:
Bio-based plastic is plastic that is based on biomass. Here we find well-known polymers such as polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA) in their bio-based variants that are chemically and properties-identical to those of fossil origin. These are usually called “drop-in solutions” in that they can directly replace the standard qualities. Perhaps more interesting are the polymers that have been developed directly from bio-based raw materials and that are biodegradable. These are often polyester-based and in this group we find probably the most well-known polylactide / polylactic acid (PLA).
A limitation in the name bio-based plastic is that at present there are no requirements for how large a share a material quality must contain in order to be called bio-based. On the positive side, however, more and more manufacturers state the percentage of bio-based raw material and there are various possibilities for obtaining a certification of their raw material, for example via ICSS.
Biodegradable plastics are plastics that are suitable for degradation by biological processes. The range of degradability of different polymers is large and industrial composting processes are most often referred to here when classifying their material as biodegradable. An industrial process is far from the conditions that apply in a home compost or in nature, which easily gives the end consumer a false impression that the problem of plastic waste in our environment will soon be solved. In addition to the 100% bio-based plastics or plastic mixtures that are degradable, this group also includes plastics of fossil origin, such as polybutyl adipate phthalate (PBAT).
The standards EN 13432 and EN 14995 set requirements for how a biodegradable plastic material is to be degraded in an industrial composting process. Basic requirements in these standards are that 90% atomization must take place within 3 months and that the material is biodegradable to carbon dioxide and water to at least 90% within 6 months. An industrial composting process usually involves stirring, aerating and moistening the compost where the temperature during certain periods is 50–60 ° C.
At present, bio-based plastics make up just under 1 per cent of the 370 million tonnes of plastic produced annually in the world. In 2020, the production capacity for bioplastics was 2.1 million tonnes, with non-biodegradable plastics accounting for 42%. Dominant among them today are PE, PET and PA, but bio-based PP (polypropylene) that was introduced on the market in 2019 is the plastic that is expected to grow the most. Among the biodegradable, the “old” starch-based plastics still dominate, but here PLA, PBS (polybutyl succinate) and PHA (polyhydroxyalkanoate) also have a strong position where the latter is expected to have the most positive development.
Areas of use
As the development of new types and qualities of bio-based plastics with better properties progresses, they are gaining ground in more and more areas of use. Today, however, it is still use in packaging that is the totally dominant area. There, 47% of the total volume of bio-based plastic is used, ie a slightly larger share than the 40% of the total volume of plastic used in packaging.
Due to comparatively high manufacturing costs, bio-based plastics have found it difficult to enter the often price-squeezed market with plastic materials, which is reflected in a large number of commercially unsuccessful investments with closed projects or companies as a result.
Different types of raw materials
The combination of reduced carbon footprint and the ability to recover discarded products through composting are the most obvious benefits that have driven the development of bio-based plastics. In the second scale is the somewhat controversial use of edible crops and arable land for other than food production. Therefore, the trend is increasingly towards finding raw materials and processes that do not affect the earth’s food supply. Today we are talking about three generations of raw materials for bio-based polymers.
First generation raw materials
First-generation raw materials include the use of different types of crops, such as sugar cane, sugar beet and corn. Here, plastic thus competes with food. If you look at the proportion of the world’s agricultural land that is used for the production of bio-based plastics, today it is a vanishingly small proportion corresponding to 0.05% of arable land. By comparison, about 4% of arable land is used for biofuels. Although the proportion may seem small, it can mean a great impact on biological diversity when, for example, rainforests are used for the cultivation of, among other things, sugar cane or oil palms.
Second generation raw materials
Second-generation raw materials are raw materials that do not compete with food production at all, but originate from waste and by-products. Examples here are used cooking oil, technical corn oil (by-product of ethanol production), slaughterhouse waste and tall oil.
Third generation raw materials
The third generation is in its infancy, but here raw materials are developed for plastic production from, for example, seagrass, algae and CO2.
Chemical recycling offers other possibilities
In this context, it can also be mentioned that, in addition to various purely mechanical recycling techniques, most projects are underway where processes with chemical decomposition of plastics are being developed, where after various process steps new raw material is obtained for the manufacturing process of new plastic.
Do bio-based plastics contribute to a more sustainable society?
If you consider bio-based plastics from a sustainability perspective, they do not give unequivocally positive effects. If you start with the raw material, it is of course renewable, but the main source today, some type of crop, has a negative impact on the world’s food supply and biodiversity, but at the same time a comparatively low carbon footprint in the production process.
In terms of properties, the biodegradable plastics have technical limitations, which means that they are often used for disposable products and packaging, and in parallel with this, they cause mixing problems in today’s traditional mechanical recycling of plastic packaging. If you get an ever so small mixture of a biodegradable plastic, this can have a major negative impact on the properties of the recycled material.
It is very important, in addition to the continued development of bio-based and biodegradable plastics, to have a greater focus on reducing the amount of plastic waste, and an initiative was recently started here by a group of large chemical companies and plastic users.
Bio-based plastics and AMB
The products that AMB manufactures today often have very high demands on the plastic’s properties and service life. This means that the possibility of using bio-based and biodegradable plastic has not emerged until today. Our customers ‘products are usually intended for a lifespan of 5–10 years and then today only bio-based “drop-in” plastics are conceivable and it is mainly in this area that we monitor the plastic producers’ further efforts.
It is still worth mentioning our ongoing work with our customer inne by Feral GmbH where our goal is to replace two fossil-based plastics, in a disposable product, with bio-based and biodegradable plastics.