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Can the current composite packaging bag be 100% degradable?

The main components of the composite packaging bag are made of various plastic materials, most of which are PE, PA, PET, BOPP, YOPP, CPP, etc. The molecular structure of these materials is tight, and it takes more than 100 years to fully degrade. time. The emergence of degradable materials seems to solve this problem. But the current penetration rate, and whether it can be 100% degradable, is still a problem? Some can even be called pseudo-degradation. For example, starch-based (bio-based) is mainly composed of ordinary high-density polyethylene, low-density polyethylene, starch and various additives. The principle is to use starch to decompose and compare. If it is fast, it increases the area of the surface of the bag in contact with the air, accelerates the oxidation process, and disintegrates into small plastic particles in a short time. These small particles are difficult to degrade, and the final pollution ratio is higher. Ordinary plastic bags are even more serious. To achieve full degradation, it must be decomposed in the environment of bacteria and light oxidation, and become small molecules such as water, carbon dioxide and methane. Of course, there are also degradable materials with relatively mature degradation, such as PBAT and PLA. But issues of penetration and functionality remain to be resolved. 1. In terms of material properties, taking composite food packaging bags as an example, it is required to be safe and stable, non-toxic and tasteless, non-permeable and volatilized, with certain toughness and air tightness. As for degradable materials, PBAT is a copolymer of aliphatic (butylene adipate) and aromatic (butylene terephthalate). The processing performance of PBAT is very similar to that of LDPE. It can be blown by LDPE processing equipment. membrane. However, the tensile strength and air tightness cannot meet the requirements of composite food packaging bags. Another degradable PLA polylactic acid is made from starch raw materials proposed by renewable plant resources (such as corn, cassava, etc.). Starch raw material is saccharified to obtain glucose, and then fermented from glucose and certain strains to produce high-purity lactic acid, and then chemical synthesis method is used to synthesize polylactic acid with a certain molecular weight. Although it has good biodegradability, it needs to be completely degraded in a specific environment. into carbon dioxide and water. Since most of the materials are starch, there are still some problems with stability, and some flavors will be emitted into the food. 2. In terms of production cost, due to technical reasons, the production cost of degradable materials can be much more expensive than ordinary plastic films. As far as the current market is concerned, it is difficult for most merchants to accept it. Summary: According to the standard of composite packaging bags, there is still a certain gap between degradable materials and ordinary materials, mainly because users and merchants cannot accept the cost and performance of degradable materials. The main use of degradable materials today is in single-layer plastic bags. Vacuum packaging bags, tea packaging bags

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