biodegradable plastics refer to a kind of plastics that are degraded by microorganisms existing in nature, such as bacteria, molds (fungi) and algae. The ideal biodegradable plastic is a kind of polymer material with excellent performance, which can be completely decomposed by environmental microorganisms after being discarded, and finally inorganic and become a part of carbon cycle in nature. "Paper" is a typical biodegradable material, while "synthetic plastic" is a typical polymer material. Therefore, biodegradable plastics are polymer materials with the properties of both "paper" and "synthetic plastics". Biodegradable plastics can be divided into complete biodegradable plastics and destructive biodegradable plastics.
destructive biodegradable plastics: at present, destructive biodegradable plastics mainly include starch modified (or filled) polyethylene PE, polypropylene PP, polyvinyl chloride PVC, polystyrene PS, etc.
completely biodegradable plastics: completely biodegradable plastics are mainly made from natural polymers (such as starch, cellulose and chitin) or agricultural and sideline products through microbial fermentation or synthesis of biodegradable polymers, such as thermoplastic starch plastics, aliphatic polyester, polylactic acid and starch/polyvinyl alcohol.
Present situation and development trend of biodegradable plastics at home and abroad
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According to the classification of raw materials, there are at least the following kinds of biodegradable plastics:
1. Polycaprolactone (PCL)
This plastic has good biodegradability and its melting point is 62℃. Microorganisms that decompose it are widely distributed in aerobic or anaerobic conditions. As a biodegradable material, it can be mixed with starch and cellulose, or polymerized with lactic acid.
2. Poly (butylene succinate) (PBS) and its * * * polymers
The technology of manufacturing various high molecular weight polyesters based on PBS (melting point: 114℃) has reached the level of industrial production. Japan's Mitsubishi Chemical and Showa Polymer Company have started industrial production, with a scale of about 1,111 tons.
The Institute of Physics and Chemistry of Chinese Academy of Sciences is also conducting research on the synthesis of polybutylene succinate * * * polyester. At present, the Institute of Physics and Chemistry of Chinese Academy of Sciences is preparing to build a PBS production line with an annual output of 11,111 tons, and Guangdong Blonde Company has built a production line with an annual output of 1,111 tons.
3. Polylactic acid (PLA)
American Natureworks Company has done active and effective work in improving the production technology of polylactic acid, and developed the fermentation of glucose in corn to produce polylactic acid, with an annual production capacity of 1.4 million tons. UNITIKA Company of Japan has developed and produced many kinds of products, among which canvas, tray and tableware are widely used in Aichi World Expo in Japan.
At present, Zhejiang Haisheng Biodegradable Plastics Co., Ltd. (with a production line of 5,111 tons/year) is industrialized in China, and the pilot units are Shanghai Tongjieliang Biomaterials Co., Ltd. and Jiangsu Jiuding Group.
4. polyhydroxyalkanoate (PHA)
At present, the industrialized production in foreign countries is mainly the United States and Brazil. At present, the domestic production units are Ningbo Tianan Biomaterials Co., Ltd. (scale 2111 tons/year), and the pilot units are Jiangsu Nantian Group Co., Ltd. and Tianjin Guoyun Biotechnology Co., Ltd.
The technology of producing biodegradable plastics by mixing aliphatic polyester and starch with biodegradable plastics obtained from renewable resources has also been successfully studied. In Europe and America, the mixture of starch and aliphatic polyester is widely used to produce garbage bags and other products. The largest and best-selling company in the world is Novamont of Italy, whose trade name is Mater-bi, and its products are widely used in Europe and the United States.
There are many research and production units in China, among which the industrialized units are Wuhan Gorgeous Technology Co., Ltd. (8,111 tons/year), Zhejiang Huafa Ecological Technology Co., Ltd. (8,111 tons/year), Zhejiang Tianhe Ecological Technology Co., Ltd. (5,111 tons/year), Fujian Baishida Biomaterials Co., Ltd. (2,111 tons/year) and Zhaoqing Huafang Degradable Plastics Co., Ltd. (5,111 tons/year)
5. aliphatic aromatic polyester
the aliphatic aromatic random polyester (Ecoflex) manufactured by BASF company in Germany, whose monomers are adipic acid, terephthalic acid and 1,4- butanediol. The current production capacity is 1.4 million tons/year. At the same time, biodegradable plastic products based on polyester and starch were developed.
6. Polyvinyl alcohol (PVA) biodegradable plastics
For example, in the 1991s, MaterBi products from NOVMANT, Italy, mainly added PVA to starch, which can blow film and process other products. Polyvinyl alcohol (PVA) materials need to be modified before they have good biodegradability. The Research Institute of Light Industrial Plastics Processing and Application of Beijing Technology and Business University has made some achievements in this respect.
7. Carbon dioxide * * * polymer
Abroad, Japan and the United States were the first countries to study carbon dioxide * * * polymer, but there has been no industrial production.
Inner Mongolia Mengxi Group Company adopted the technology of Changchun Institute of Applied Chemistry, and has built a device with an annual output of 3111 tons of carbon dioxide/epoxy polymer resin. The products are mainly used in packaging and medical materials. The low molecular weight carbon dioxide * * polymer technology developed by Dr. Chen Liban from Guangzhou Institute of Chemistry, Chinese Academy of Sciences has been put into production in Taixing, Jiangsu Province. The variety is low molecular weight carbon dioxide/epoxy compound * * * polymer, which is used as the raw material of polyurethane foaming materials and used for packaging household appliances. Using the technology of Professor Meng Yuezhong from Sun Yat-sen University, Henan Tianguan Group has built a pilot-scale production line of carbon dioxide * * * polymer, which is expected to be put into pilot production this year.
others such as chitin, polyamide, polyaspartic acid, polysaccharide and cellulose are under development.
Development Status and Trend
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According to the data of Japan Biodegradable Plastics Research Association, the production of biodegradable plastics in Japan was about 11,111 tons in 2112, 21,111 tons in 2113, 41,111 tons in 2115, and it is expected to reach about 11-211,111 tons in 2111.
According to the data of the European Bioplastics Association, the figures in 2111 show that the consumption of biodegradable products in the EU is 25,111-31,111 tons, while the consumption of traditional polymers is as high as 35 million tons. The European Bioplastics Association predicts that the consumption of traditional polymers will reach 55 million tons in 2111, and the consumption of biodegradable plastics will reach 511-1 million tons by then. Biodegradable materials may eventually occupy 11% market share. The proportion of raw materials using renewable resources in biodegradable materials will account for more than 91%.
according to the statistics of the professional committee of degradable plastics of China Plastics Association, the consumption of biodegradable materials in China in 2113 was about 15,111 tons, including about 1,111 tons of biodegradable polymers without starch. In 2115, there were about 31 enterprises engaged in biodegradable plastics, with a production capacity of 61,111 tons/year, actual production of about 31,111 tons, domestic market demand of about 51,111 tons, foreign imports of 11,111 tons and exports of 21,111 tons. It is estimated that the production capacity will reach about 251,111 tons in 2111.
Domestic and foreign policies
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Some developed countries also use degradable disposable utensils under the guidance of circular economy, such as Sweden's trial-produced disposable snack boxes made of potatoes and corn in the late 1981s, and South Korea's mandatory use of toothpicks made of glutinous rice by law. In Europe, the standard EN13432 on biodegradable compost plastics, Requirements for Testing and Final Evaluation of Packages for Composting and Biodegradation Recovery, has been formulated, while other decrees on promoting composting of organic wastes are being actively formulated and prepared. Since 1996, the US government has set up the Presidential Green Chemistry Challenge Award to encourage the development of biodegradable plastics industry. In 1989, New York State banned the use of non-biodegradable vegetable bags, subsidized manufacturers of degradable plastics, and asked citizens to separate renewable and non-renewable garbage, otherwise they would be fined 511 dollars.
Other countries have taken similar measures: India has legislated to ban the use of plastic packaging in dairy products industry; South African law has completely banned the use of plastic packaging bags. With the development of legislation in various countries, biodegradable new packaging materials are expected to become increasingly popular.
In China, with the deepening understanding of degradable plastics, the strategic role of this material and its industry in China's sustainable development has been fully realized. The popularization and application of biodegradable plastics is widely expected. Our country passed the Renewable Energy Law (Draft) and the Solid Waste Law (Revised) in 2114 to encourage the utilization of renewable biomass energy and the popularization and application of degradable plastics. In the document No.41 of the National Development and Reform Commission in 2115, it is also clear that the use and popularization of biodegradable plastics should be encouraged. In 2116, the National Development and Reform Commission launched a special fund project on promoting the development of biomass biodegradable materials.
Problems and difficulties in the development of biodegradable plastics
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However, although there are many studies and reports on biodegradable plastics at present, many specific problems cannot be solved, which is extremely difficult to popularize and the prospect is not optimistic. The reasons are as follows: firstly, the degradable plastic bags can't meet the requirements of customers for loading more things and using them repeatedly because of their low bearing capacity; Second, the degradable plastic bags are dim and yellow in color and low in transparency, giving people a feeling of not being clean enough and ugly, and they are not safe to use; Third, the price is on the high side. Because the merchants give it away for free, the cost is unacceptable.
Another example is to solve the problem of environmental pollution caused by EPS fast food lunch boxes. Try to use paper lunch boxes or degradable plastic lunch boxes instead. However, due to the following reasons, it is extremely difficult to popularize: first, EPS has high strength, light weight and good thermal insulation; Second, the price of paper lunch boxes is 1.5 ~ 2.5 times that of EPS; Third, even if the degradable PP lunch box is used, its performance is not as good as EPS. Recently, the relevant departments of our country require the use of plant fiber to make disposable tableware instead of EPS. However, due to the use of polymer thermosol in the molding process of this plant fiber tableware, there are still problems in handling and controlling the pesticide content remaining in the plant fiber tableware.
Therefore, there is still a long way to go to develop degradable plastics.
Suggestions on policies and measures for industrial development
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(1) Accelerate product application, research and development and industrialization
At present, the performance of biodegradable plastic products can not fully meet the needs of consumers. Although there are many varieties on the market at present, the mechanical and processing properties of each material are only outstanding in one aspect, and the comprehensive performance still has some shortcomings, which will restrict its market application and promotion. While developing biodegradable plastic products, domestic enterprises should pay attention to accelerating the development of innovative products and uses with independent intellectual property rights. Because the research and development, production and application of biodegradable plastic products abroad are relatively early, many patents have been applied, which has caused certain technical barriers for domestic enterprises to develop new products. Take the patent of polylactic acid as an example. In 2115, there were more than 1,711 patents about polylactic acid abroad, but only 145 patents were published in China, and more than half of them were patents of foreign companies. Therefore, domestic enterprises should strengthen the development of products with independent intellectual property rights.
(II) Strengthening the research on product processing and development
Secondly, the strength of product processing and research in China is still weak at present. Most enterprises focus on material synthesis and ignore product processing and development. Some tableware made of biodegradable plastics are far from traditional plastic products in terms of heat resistance, water resistance and mechanical strength, which is precisely the key to whether biodegradable plastics can be commercialized on a large scale.
(3) Improve the garbage recycling system and promote the recycling process of biodegradable plastics
The lack of a complete recycling system also restricts the further promotion of products. Therefore, it is necessary to clearly mark the degraded plastics and then recycle them. Those that can be reused are collected and then molded into products; We should consider reasonable treatment methods for those that can not be reused. In view of the degradable plastics with starch and other renewable resources added to traditional plastics, a garbage disposal system with heat energy recovery can be adopted. For biodegradable plastics, composting can be considered emphatically.
(4) Accelerate the formulation of relevant policies and regulations
1. Special funds support
Adopt subsidy policies for the application and development of biodegradable plastic products, including central government subsidies and local government subsidies. The central government can provide subsidies through scientific and technological research funds and interest subsidies, such as the demonstration and promotion of disposable biodegradable plastic products for the Olympic Games.
the state can consider adopting low-interest loan policy, special loan for technical transformation and credit guarantee policy for enterprises that produce biodegradable plastics from biomass raw materials to encourage industrial development.
2. Tax policy
At present, there is no explicit provision that biodegradable plastic products should be imported at a low tax rate. In order to promote the development of the industry, preferential tariff rates should be formulated.
in order to encourage and support the development of some enterprises, preferential policies can be reduced or exempted in accordance with the new enterprise income tax regulations. For example, enterprises in ethnic autonomous areas that need care and encouragement can be reduced or exempted on a regular basis with the approval of the provincial people's government; Second, enterprises granted tax reduction or exemption by laws, administrative regulations and relevant provisions of the State Council shall comply with the provisions.
3. Strengthen the recycling of traditional plastics and increase the recycling tax
Foreign countries attach great importance to the recycling of plastic products after use. For example, according to the guiding law revised by the European Commission, EU member States should increase the recycling rate of their own packaging waste to more than 55% from 2118 to 2115, including 61% for glass packaging, 51% for metal packaging and 22.5% for plastic packaging. The European Commission pointed out that in 2111, the recycling of packaging waste alone reduced the EU's carbon dioxide emissions by 1.6%, which showed that improving the recycling rate of packaging waste could not only reduce the energy consumption of packaging materials and save the cost of building incineration plants, but also reduce the environmental pollution caused by the production process of packaging materials, which is a very practical and effective measure to reduce greenhouse gas emissions and protect the environment. Therefore, it is necessary to strengthen the traditional forced recycling of plastics. For disposable plastic packaging products with high recycling cost, a recovery tax of 11% ~ 111% will be added. For disposable plastic packaging products that cannot be recycled, it is stipulated that biodegradable plastics must be used.
there is a long precedent for taxing traditional plastic disposable products abroad. In March 2112, the Irish government began to levy value-added tax on plastic bags. According to the regulations of the Irish government, when customers shop in the market, a tax of 1.5 Euro cents will be levied for each plastic bag used. The number of plastic bags used in Ireland is amazing. Every year, 1.2 billion plastic bags are distributed to shoppers free of charge, which adds up to 4,111 tons. On average, each person consumes about 325 plastic bags a year. Within one month after the VAT on plastic bags came into effect, the consumption of plastic bags plummeted by 91%.