Biodegradable plastics: a concept that needs to be correctly understood

The emergence of biodegradable plastics is seen as a tool to deal with plastic pollution, especially the environmental pollution of plastic food contact materials such as disposable straws. “Automatically disappear without treatment” is a general perception or expectation of biodegradable plastics.

April 2019, "Environmental Science & Technology" published a recent study at the University of Plymouth, UK, pointed out that part of the logo after three years can be used without biodegradable plastic bags placed in different natural environmental conditions; assessed oxygen Degraded or biodegradable plastic bags do not show better degradation than traditional plastic bags. The article has once again triggered concerns about the role of biodegradable plastics. The European Bioplastics Association, which represents the industry, questioned the scientific nature of the study and claimed that the study misled the value of biodegradable plastics and compostable plastics.

It can be said that the role of biodegradable plastics in the control of plastic pollution has been debated for a long time. In addition to the uncertainties of policies, unsound standards, and disputes in scientific research, the public and industry are biodegradable plastics. Unclear and chaotic concepts are also an important cause, resulting in misuse, misuse of biodegradable signs, and even false publicity.

Compostable plastic = biodegradable bag?

Not exactly equivalent, compostable plastics are a class of biodegradable plastics. Biodegradable plastics also include plastics that can be biodegraded in an anaerobic manner.

Compostable Plastics refers to the mineralized inorganic salts and new biomass that can be converted into carbon dioxide, water and its elements in a certain period of time under the composting conditions by microorganisms. Heavy metal content, toxicity test, residual debris, etc. of compost should comply with the relevant standards. Compostable plastics can be further divided into industrial compost and garden compost. The compostable plastics on the market are basically biodegradable plastics under industrial composting conditions.

Because compostable plastics are biodegradable under conditions, if the compostable plastics are discarded at will in the natural environment (such as seawater, mud), these plastics degrade very slowly in the natural environment and cannot be completely degraded into carbon dioxide in a short time. And water, etc., its adverse effects on the environment are not substantially different from traditional plastics. In addition, studies have indicated that biodegradable plastics, such as those incorporated into other recyclable plastics, can degrade the properties and properties of the recycled materials.

Biodegradable Ciothing Bag

How to regulate the identification of biodegradable plastics? There are no mandatory standards or regulations for biodegradable plastics in China. The relevant standard is GB/T20197-2006 "Definition, Classification, Marking and Degradation Performance Requirements for Degradable Plastics", which stipulates that the degradable plastic label should contain the main raw materials and composition information of the product, the degradation type or degradation mode of the plastic. And the standard number.

The European Bioplastics Association recommends in its published guidelines that when a product claims to be biodegradable, the product should state what degradation criteria (certification instructions and labeling) it meets, when it can be completely degraded, and to ensure that it is completed. The location/condition of the degradation process. In North Carolina and Alabama in the United States in 2013 (HB 315, Senate Bill 298), plastic products marked with biodegradable, biodegradable or compostable plastics should be marked as "non-recyclable, not recycled" to avoid Mix in other recyclable plastic products.

Faced with the challenge of environmental hazards of plastic waste and marine micro-plastics, the application of biodegradable plastics in food contact materials has been more and more respected and concerned. China's biodegradable food contact materials industry is facing a good development prospect.