Garbage bags are very common in our daily life, but have you ever seen environmentally friendly compostable garbage bags? Do you know what compostable bags are? Then this article will give you a deep understanding of compostable garbage bags.
What Is a Compostable Bag
Compostable bags (biodegradable garbage bags) are plastic bags that can biodegrade under certain conditions. They are usually made of natural materials such as corn starch and do not contain any plastic components. Such bags can quickly decompose into water, carbon dioxide and biomass in household and industrial composting environments, thereby reducing the long-term impact of plastic waste on the environment and achieving the recycling of resources.
What Are Compostable Bags Made Of
Main raw materials
Plant-based materials:
- Polylactic acid (PLA): Made from corn starch fermentation, with strength close to nylon, suitable for film and fiber products;
- Starch composite materials: Contains more than 90% starch, adds PBAT (degradable polyester) to enhance performance, and can be composted and decomposed within half a year;
Biological polyesters:
PHA (polyhydroxyalkanoate), synthesized by microbial fermentation, can be degraded in the marine environment.
Production process
- Mixed granulation: Mix starch, PLA and other raw materials with plasticizers, granulate and extrude into film at high temperature;
- Blow molding: The bag body is made by a film blowing machine, and the sealing is completed by heat sealing technology.
Compared with traditional plastic bags: Traditional PE bags rely on fossil fuels and take hundreds of years to decompose; compostable bags are made of renewable raw materials, reducing carbon emissions by more than 60%.
Certification standards and market supervision
International certification system
Industrial composting certification: EU EN 13432, US ASTM D6400, requiring decomposition within 6 months under composting conditions;
Household composting certification: such as Australia AS 5810, verifying decomposition ability at room temperature.
Chinese standards and supervision
GB/T 38082-2019: stipulates that the biodegradability of biodegradable shopping bags must be ≥ 60%;
Policy promotion: Before 2025, Shanghai, Guangdong and other places will completely ban the use of non-degradable plastic packaging bags, and the replacement rate target for the express delivery industry will reach 90%.
Identify authenticity: Check authoritative signs such as BPI and OK Compost, and be wary of “filled starch plastics” (only partially degradable)
Advantages and Disadvantages
Advantages
Environmentally friendly: Reduce microplastic pollution and support the recycling of organic waste;
Policy support: Plastic restrictions in various countries drive market demand, and the Chinese market size is expected to exceed 20 billion yuan;
Versatility: Applicable to high-end fields such as food packaging, agricultural film, and medical sutures.
Limitations
High cost: The price of raw materials is 2-3 times that of traditional PE bags, but large-scale production can reduce costs by 30%;
Facility dependence: Industrial composting plants are required, and the decomposition time of household composting is as long as 1-2 years
How to choose a Compostable Bag
- Capacity and thickness: For household kitchen waste, it is recommended to choose a 3-gallon capacity, with a thickness of ≥0.025mm to prevent rupture5;
- Certified brands: Recommended brands such as BioBag and EcoSafe that have passed EN 13432 certification68.
Precautions for use
- Storage conditions: Avoid high temperature and humidity environments. The shelf life of unopened bags is 2-3 years8;
- Disposal method: Confirm whether the local composting facility accepts industrial compost bags. Household compost needs to be cut into pieces to accelerate decomposition.
FAQ
How long does home composting take?
Starch-based bags take 6-12 months, and PLA bags require industrial composting conditions8.
Can they be degraded in the ocean?
Only special materials such as PHA can be decomposed in seawater, and most need land composting69.
How to avoid pseudo-environmentally friendly products?
Look for BPI and TÜV certification to test whether the biodegradability rate meets the standard
