What is bio-based plastic?
A bio-based plastic is completely or partially manufactured of renewable raw materials for example wood, corn or sugar beet. Conventional, fossil-based plastic is made from raw oil and natural gas.
The raw materials in itself contain bio-mass like cellulose, starch or sugar. They can also be manufactured from waste and by-products.
For more information:
Bioråvara till plast – nuläge och trender (in Swedish, ivl.se)
There are biobased plastics that contain the same polymers as fossil-based equivalent of, for example polypropylene. They are called drop-in plastics.
At present there is not a minimum limit for a plastic to be called bio-based. But a content of at least 20 percent bio-based carbon is often required to receive different labels and certifications for bio-based products. Although the current situation does not require a minimum limit for a plastic to be called bio-based it must be stated how many percent is bio-based.
Bio-based plastic is also plastic. Certain products that contain bio-based plastic are wrongly marketed as “plastic-free”. The bio-based plastic does not have to be biodegradable it could have been designed to be as durable as other plastic.
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 both 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.