The white pollution of the environment caused by traditional plastic bags is getting more and more serious. As people’s awareness of environmental protection continues to increase, degradable plastic bags, fully biodegradable plastic bags, fully degradable plastic bags, and various new types of degradable plastic bags have come out. Both bio-based plastics and biodegradable plastics are new materials that are environmentally friendly and can sustainably replace traditional plastics currently mainly made of petroleum.
“Degradable”, “biodegradable” and “compostable” are terms that people often refer to when talking about these materials. It is easy to confuse them. They are similar but different. So what is the difference between them? The following professional flexible packaging manufacturer Shunxingyuan Packaging will explain it.
1. Degradable plastic bags
Degradable plastic bags include plastic bags that can be degraded by physical and biological factors (light or heat, or microbial action). The so-called aerobic degradation (that is, accelerated degradation by catalysts or activators at high temperatures) or photodegradable starch-polyethylene plastics will cause some environmental problems. These degradable plastic bag materials do not degrade as fast as compostable plastics and may leave debris.
These degraded water-repellent fragments have a large surface area and may migrate to groundwater and soil, where they adsorb and retain some hydrophobic and highly toxic substances on their surface. Such as PCB and DDT, the toxic substance content is as high as 1 million times the background content, which is enough to become a delivery system for toxic substances in the environment. Therefore, it is necessary to ensure that the product is completely biodegradable in a very short time determined by the treatment facility.
2. Biodegradable plastic bags
Biodegradable plastic bags are those plastic bags that can be completely digested by the microorganisms in the processing system as food for energy (entering the food chain). The determination of this complete microbial digestion/utilization is measured by testing whether the carbon element of the test plastic can be completely converted into CO2 through the microbial process occurring in the cell.
3. Compostable plastic bags
In addition to being biodegradable by microorganisms, there must be a time requirement for a plastic bag to be called “compostable” plastic. For example, ASTM 6400 (specification for compostable plastics), ASTM D6868 (specification for biodegradable plastics used for surface coating of paper or other compostable media) or EN 13432 (compostable packaging) standards stipulate that these materials are used in industrial composting environments It should be biodegraded within 180 days.
The industrialized composting environment refers to the prescribed temperature of about 60°C and the presence of microorganisms. According to this definition, compostable plastics will not leave fragments longer than about 12 weeks in the residue, contain no heavy metals or toxic substances, and can sustain plant life.