According to the definition of plastic degradation, there are basically three types of plastic flexible packaging materials in the world: 1. Biodegradable plastic flexible packaging materials; 2. Degradable plastic flexible packaging materials; 3. Non-degradable plastic flexible packaging materials. On the basis of these three basic concepts, it can be further subdivided according to the chemical composition. Of course, according to different definitions, some people divide it into all degradable plastic flexible packaging materials, partially degradable plastic flexible packaging materials, and refractory plastic flexible packaging materials.
1. Biodegradable plastic flexible packaging materials
If a certain kind of plastic flexible packaging material can become carbon dioxide and water under certain realistic conditions, and this material meets most of the international standards and national standards, it can be called a biodegradable material. The so-called real conditions refer to temperature, humidity, microorganisms and other conditions. The currently practical biodegradable plastic flexible packaging materials include: polylactic acid, starch-polyester mixture, polyester-polylactic acid mixture, and polyester.
2. Degradable plastic flexible packaging materials
If a material is triggered to decompose into basic elements under certain conditions and meets most of the international standards and national standards, it is a degradable material. The difference between biodegradable and biodegradable materials is controversial because they both have the commonality of releasing carbon dioxide and water. For some degradable materials, the only reason for not meeting the biodegradation standards is the longer degradation time. The other most difference is that strong heat, humidity, or ultraviolet radiation are often the main factors that trigger the degradation of degradable materials; while biodegradable materials are microbes. Typical ones are: low density polyethylene/high density polyethylene-oxidant mixture.
3. Non-degradable plastic flexible packaging materials
Although the non-degradable plastic flexible packaging material can be broken into pieces, it will not be decomposed into basic elements, nor will its chemical composition be changed. For example, put a small amount of starch into a discarded polyethylene bag, and the end result is that the bag shatters when exposed to moisture. But the polyethylene molecule has not changed, just like cutting the bag with scissors. Common ones are: low-density polyethylene/high-density polyethylene, low-density polyethylene-starch mixtures.