[Abstract] In order to make the domestic packaging industry understand the development trend of green packaging and better promote the development of China's green packaging, this article categorizes the development of green packaging materials in several aspects, including recyclable or recycled packaging. Materials, lightweight, thin, non-fluorinated, high-performance packaging materials, biodegradable plastics, natural plant fiber packaging materials, edible packaging materials, modified starch and agricultural and sideline products, high polymer packaging materials, genetically modified packaging materials, green packaging aids Materials and additives for green packaging materials. And from the future direction of development and issues that should be paid attention to, we put forward five countermeasures that China should adopt to develop green packaging materials.

Keywords: Green packaging materials; Harmless; Recycling; Recycling

In order to solve the contradiction between packaging and the environment and develop green packaging vigorously, all countries in the world have focused their attention on developing green packaging materials. Green packaging material is the material with the lowest environmental load and the highest recycling rate in the whole life cycle. Green packaging material is the core of green packaging. It not only reduces and eliminates the pollution to the environment and relieves the pressure on the ecological environment, but also saves resources, replaces some of the scarce or valuable resources, and recycles used resources. The countries of the world attach great importance to it and have invested a lot of funds and manpower in development. At present, many important achievements have been made.

1 Recyclable or recycled packaging materials

Recycling, recycling, and energy use of packaging materials are the most practical and feasible steps in the development of green packaging materials at the present stage. They are the most active waste treatment methods for protecting the environment and promoting the recycling of packaging materials, and also the development of green packaging. The most important thinking orientation of the material.

1) Reuse materials (articles). Many countries in the world attach importance to the development of product recycling technology, and through the deposit recovery system, beer, beverages, soy sauce, vinegar and other glass bottles or polyester bottles are used repeatedly. For example, Sweden and other countries have developed a sterilizing washing technology to reuse PET beverage bottles and PE milk bottles for more than 20 times; Welman, the Netherlands, and Johnson, the Netherlands, have performed 100% recovery of PET containers and received FDA approval. It can be hot-filled without degradation and is cheaper than normal PET or laminated PET. It can be directly used in the packaging of beverages and foods in Europe and the United States; after the carbonate bottles are recovered in Germany, they are washed and rinsed with high-temperature sterilization. After that, it can be reused 100 times.

Japan attaches great importance to the development of the 250L steel drum storage tanks. After renovation, washing, drying, and painting, the tanks can be used repeatedly.

2) Recycling materials. Recycling is a good way to solve solid waste. In many countries, it has become an effective way to solve the source of materials and mitigate environmental pollution. China's resources are not abundant, so the development of recyclable packaging materials and corresponding recycling technologies are particularly important. However, the cost of recycled resins is generally higher than that of the original resins, and their quality and use are not as good as those of the original resins, and they are used more cheaply. Materials, plastic films, plastic bottles (especially PET bottles), etc. Recycling of plastic packaging waste has now received the attention of many large companies in industrialized countries, and has invested a lot of manpower and material resources for the recycling of plastic waste (including direct recycling of raw materials, physical modification, recycling, Chemically modified recycling and other technologies have been studied, and the proportion of recycled uses is increasing year by year. If polyester bottles are recycled, they can be recycled using both physical and chemical methods.

The physical method refers to directly purifying the recovered plastic after comminution. It cannot have any residual contaminants. It can then be used directly in remanufacturing packaging containers, or it can be used as a sandwich material in two layers of primary resin layers to crush and wash the polyester. Multilayer PET packaging containers;

The chemical method means that after the recovered PET is pulverized and washed, the depolymerization agent such as methanol, water, ethylene glycol, or diethylene glycol is used to depolymerize all of the PET into monomers or partly depolymerize into oligomers after purification by a basic catalyst. The monomer or oligomer is re-polymerized into a recycled PET resin packaging material. For high-expanded polystyrene (EPS) packaging materials, Sony Corporation of Japan used a citrus oil dissolution method to dissolve the recovered EPS into the oil extracted from the orange at room temperature to reduce its volume to 5 % or less, and then separate out the recycled high-quality polystyrene, achieving 100% recycling of the EPS.

After the glass and metal packaging containers are discarded, they are generally melted or remelted by remelting and used as raw materials.

After the use of paper and paperboard is abandoned, new paper pulp is obtained through the disintegration, desorption and bleaching to produce recycled paper. According to statistics, in developed countries, magazine publications have used 100% recycled paper, 80% of packaging paper products use recycled pulp, and recycled paper for books has also reached 40%. In Britain, the United States, and Japan, recycled paper has become a major industry.

(to be continued)