Degradable materials can generally be divided into four categories: photodegradable plastics, biodegradable plastics, photo/biodegradable plastics and water-degradable plastics. Photodegradable plastics are photosensitizers mixed into plastics. Under the action of sunlight, the plastics gradually decompose. But its disadvantage is that the degradation time is affected by sunlight and climate environment, so it cannot be controlled. Biodegradable plastics refer to plastics that can be decomposed into low-molecular compounds by microorganisms that exist in nature, such as bacteria, molds, and algae under certain conditions. Such plastics are convenient to store and transport, and have a wide range of applications. Light/biodegradable plastics are plastics that combine the dual characteristics of light-degradable plastics and biodegradable plastics. At present, the biodegradable plastics developed in my country are mainly biopolyesters such as polylactic acid (PLA), polyhydroxyalkanoate (PHA), carbon dioxide copolymer (PPC) and so on. Polylactic acid (PLA) is made by polymerization of lactide monomers extracted from plant sugars, and can be completely degraded into water and carbon dioxide under industrial composting. Polyhydroxyalkanoates (PHA) are aliphatic copolyesters with different structures synthesized by the fermentation of various carbon sources by microorganisms. They can not only be used in packaging materials, agricultural films, etc., but also be widely used in medicines, cosmetics, and Animal feed and other fields. Water-degradable plastics are plastics that can be dissolved in water because of the addition of water-absorbing substances. With the development of modern biotechnology, biodegradable plastics have become a new hot spot in research and development.

In China, the current biodegradable material technology is not mature enough, and there will basically be certain additives. If these additives are added, the plastic material will not achieve the effect of biodegradation. If it is not added, this plastic material will decompose under any circumstances, especially in high temperature places, so it is particularly difficult to store.
In addition, the use of biodegradable materials to make product molds requires specific modifications.