The morning of February 7, the State Quality Inspection Administration, the National Standards Commission approved the release of cosmetics, courier bags, fireworks and other 291 national standards, of which the new standard express delivery packaging bags should adopt biodegradable plastics.
Newly revised and released "express packaging supplies" series of national standards, according to the reduction, greening, recyclable requirements, the relevant content of the original standards were supplemented and improved. The new standard to reduce the express envelope paper, cushion film Courier bags, plastic woven bags courier bags quantitative requirements.In addition, express delivery bags also require the use of biodegradable plastics, an increase of heavy metals and the requirements of specific substances and so on.
According to statistics, a total of 12 billion to 13 billion courier bags are used nationwide in 2017, including electricity suppliers and express delivery companies (accounting for 60% of the total), and traditional materials have a biodegradation cycle of more than 200 years, causing serious environmental pollution. However, biodegradable plastics Can greatly speed up the degradation rate, reduce environmental pressure.
Biodegradable plastic refers to a class of plastics that are degraded by the action of microorganisms such as bacteria, molds (fungi) and algae found in nature, and are classified into two groups, biodegradable plastic and biodegradable plastic, depending on the biodegradation process Fully biodegradable plastics are readily degraded by the use of aliphatic polyesters, polyvinyl alcohol (PVA) and polyethylene glycol when chemically synthesized. Biodegradable plastics are those that are incompletely biodegradable and are commonly used in the production of olefins Plastic materials mixed with biodegradable material, the material loss of mechanical properties and shape, and through composting and biodegradability produce the same effect, because of the low cost of such plastics, this method has been used at home and abroad.
The mechanism of biodegradation has not yet been clearly defined. It is generally believed that the process is as follows: First, the microorganisms secrete hydrolases and hydrolases combine with the materials to break the polymer chains by hydrolysis to generate small molecules with a molecular weight of less than 500 g / mol Compounds, which is the first process.Next, the degradation of small molecules by microorganisms into the body, through the synthesis of microbial synthesis or conversion into microbial energy required, and ultimately converted into water and carbon dioxide to complete the degradation process.