What is bio-based plastic?
Bio-based plastic is made entirely or partly from renewable raw materials, such as wood, corn, or sugar beet. In contrast, conventional fossil-based plastic is produced from crude oil and natural gas.
These renewable raw materials contain biomass components such as cellulose, starch, or sugar, and can also be derived from waste or industrial by-products
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Bioråvara till plast – nuläge och trender (in Swedish, ivl.se)
Some bio-based plastics contain the same polymers as their fossil-based counterparts, such as polypropylene. These are known as drop-in plastics.
At present, there is no minimum threshold for a plastic to be classified as bio-based. However, a bio-based carbon content of at least 20 percent is often required to obtain various labels and certifications for bio-based products. While there is currently no mandatory minimum, the exact percentage of bio-based content must still be specified.
It is important to note that bio-based plastic is still plastic. Some products containing bio-based plastic are incorrectly marketed as 'plastic-free.' Furthermore, bio-based plastic is not necessarily biodegradable – it may be engineered to be just as durable as conventional plastics.
Does bio-based plastic break down in nature?
The term biodegradable plastic means that a plastic that can break down biologically under certain conditions, for example in an industrial compost. After decomposition natural components such as water and carbon dioxide are obtained. The plastics biodegradability depends on:
- If designed for biodegradability or composting
- The conditions it is exposed to after it has been used. Often high temperature and other specific conditions are required for complete degradation.
Many mistakenly believe that plastics marketed as “biodegradable” or “compostable” can be thrown away in nature or in the food waste. But:
- Degradable plastic can cause as much damage in nature as non-degradable plastic because the degradation of the plastic partly takes time and partly demands other conditions to break down than those found in nature, which is often the case. It is therefore important that degradable plastic does not end up in nature. Even incorrect sorting of biodegradable plastic can contribute to leakage of plastic into nature.
- Food waste in Sweden is handled by local authorities and today treated generally by anaerobic digestion. As conditions differ between composting and an anaerobic digestion process, most plastics that break down in an industrial compost cannot be broken down by anaerobic digestion. The vast majority of compostable plastics on the market are not broken down by the conditions that apply in a home compost, it generally takes an industrial compost. In Sweden, there is currently no widely developed infrastructure for industrial composting.
Plastic may be called biodegradable if it does not break down completely- the standards required for packaging recyclable through composting and biological degradation (EN13432) allows a fraction below two millimeters (specified as “visually undetectable”). Incomplete biodegradation leads to microplastics and other synthetic degradation products.
If you use bio-based or biodegradable plastic
Have this in mind if you think about using bio-based plastic or biodegradable plastic:
- It is still plastic. Some alternatives are incorrectly marketed as “plasticfree”.
- Biodegradable plastic often need industrial composting to break down. This needs to be stated in the information about the product. Industrial composting is today very unusual in Sweden, instead the food waste is treated through anaerobic digestion.
- Choose biodegradable plastic only if that function is needed for the product. Ask for information about conditions under which “biodegradable plastic” breaks down and investigate whether it is an advantage in your case. The best option with resource efficiency is material that is collected and material-recycled.
- The fact that a plastic is bio-based does not mean that it is biodegradable. Bio-based drop-in plastic works well in material recycling processes.
- Always declare how much of the plastic that is bio-based in the product! Often it is not 100 percent, which means marketing can be misleading for the consumer.
- Environmental performance of different bio-based plastics varies. Ask for information about the product’s environmental impact and choose raw materials and products with minimal impact on the environment.