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First, the impact of plastic applications on the environment According to statistics, the world's plastic consumption has increased rapidly in the past 20 years. In 2004, the total global plastic production was 224 million tons. In 2005, the total output reached 236 million tons, and the consumption reached 200 million. Ton. It is expected that by 2010, the average growth rate of global plastic consumption will reach 5.3%.
China's recyclable plastic waste is about 4 to 5 million tons per year, and about 2 million tons of waste plastics are actually recycled.
The harm caused by plastics to the environment is mainly in the following four aspects: 1. The lack of petrochemical resources.
2. The plastic processing consumes a lot of energy.
3. The production, use, by-products, emissions, and waste of plastic additives are harmful to the human body and the environment.
4, plastic products are not easy to break down and not easy to recycle, plastic waste pollution of the environment as hazardous waste.
Second, the concept of environmentally friendly plastics 1. Define plastics that will not cause irreversible damage to the environment during production, use, or disposal. That is to say, they are cost-effective, easy to recycle, use energy-saving and environmentally friendly methods, and be used in the environment. The plastic materials that are completely degraded and harmless to the natural environment, human beings, or biosphere are relatively environmentally friendly plastics.
2. Environment-friendly plastics classification 1) Recycled plastics â– Reusable plastics such as POF â– Recyclable plastics such as PET, PVAL2) Biodegradable â– Biodegradable plastics (natural polymers and modified substances) such as starch, natural cellulose Derivatives and their filled modified POF.
Fully biodegradable plastics (biotransformation synthetic modifiers) such as starch-based, aliphatic-aromatic copolyesters, polyhydroxyalkanoates, PLA.
3. Characteristics of environment-friendly plastics 1) Cleanliness can be produced by clean production, and plastic materials that can be routinely produced can be produced without the need of adding a small amount of additives.
2) Reduced, energy-saving plastic products that use homogeneous, homogenous, light-weight and bulk products or production methods that increase the availability of plastic raw materials and reduce processing energy consumption, such as gas-assisted molding, micro-hole forming, and half Melt molding, vibration molding technology.
3) Resource-based biomass resources - The use of natural polymers and plastics produced by biotransformation to obtain organic intermediates and synthetic polymer materials. Starch, straw composites, poly-β-hydroxyalkanoates (PHAS), polylactic acid (PLA).
4) Harmlessly degradable plastic products, biodegradable and hydrolyzed polymer materials such as PLA, PCL, polybutylene succinate PBS snow, PVAL.
III. Development and application status of environmentally friendly plastics at home and abroad (1) Recycled plastics 1 Development and application of recycled plastics 1) Industrial development of wood/plastic composite materials According to the research report of the United States PricinpiaPartmers Consulting Company in 2003, Europe and North America are currently the world's plastics The largest area of ​​wood material market is about 600,000 tons, of which the North American market accounts for about 85%. It is predicted that by 2010, wood/plastic composite materials in Europe and North America will increase by 14% and 18% respectively.
Wood/plastic composite materials used in: wall panels, partitions, decorative panels, building templates, highway noise separators, beach boards, dock platform boards, railway sleepers, packaging and logistics combination trays, storage racks, fences, Handrails, outdoor terraces and other transportation, construction, and public facilities.
It is predicted that by 2010, the largest application of wood/plastic composite foams is the introduction of building products. High-performance, lightweight wood/plastic composite foams will find great application in automotive interiors, doors and windows. China will continue to develop at an average annual growth rate of over 50%. The output and output value of China's wood/plastic composite materials and products will eventually form a new industrial system with a production value of 10 million tons/year or 70 billion yuan.
2) PEP bottle recycling technology Each year, the global consumption of beverage bottle waste is more than 10 million tons, and its output and consumption increase at a rate of 10% to 19% year by year. The consumption of polyester bottles in China was 1.78 million tons in 2005, and it is estimated that its recycling rate is at least 90%.
Polyester waste bottle recycling methods include physical and chemical methods. The vast majority of mechanical waste recycling is used to produce fiber, and some are used in plastic processing (non-food packaging materials and products). Chemical alcoholysis, alkaline hydrolysis, or hydrolysis of waste to produce terephthalic acid, ethylene glycol, and acetaldehyde and other substances. Physical recovery of waste bottles is the use of solid-phase polycondensation technology to improve the performance of waste, and then used for bottle filling beverages.
GE Plastics has successfully developed PBT resins and PC/PBT blends from used PET bottles. The target of this type of resin application is the automotive industry, and 80% of its output can be produced from waste waste bottles.
3) Production of high-density bricks from waste plastics Mexico will collect plastic bottles filled with shampoos, wine, mineral water, and beverages, and use molding technology to produce high-density bricks that are shock-resistant and have a long life compared to ordinary bricks. With its advantages of light weight and low cost, it can save 30% of construction costs.
4) Waste plastics to create advanced new packaging materials New Zealand has successfully synthesized waste plastic polyethylene milk bottles and waste coke bottles into a new plastic. This new type of plastic is harder than waste, and its oxygen barrier effect is increased by 2-3 times. It is very suitable for food packaging materials. With the addition of suitable additives, the electromagnetic shielding performance of the plastic is greatly improved, making it an ideal packaging material for electronic products. This new plastic can be recycled for several uses without degrading performance.
5) Classification of plastic parts in durable consumer goods 2. Recycling plastics recycling and decomposing technology 1) Pyrolysis into liquid fuels A. Conversion of waste polyolefins into aromatic hydrocarbons Kawashima Harima Heavy Industries has recently developed polyolefin plastics into benzene, The yields of toluene and xylene were: benzene 15%, toluene 20%, and xylene 15%. The remaining components are less than 10% ethylbenzene, about 30% C1 to C4 hydrocarbon gases, and waxes and cokes.
B. Depolymerization of Waste Plastics into Liquid Fuels Tokar has developed a new T-Technoloy process and applied it to the recycling of waste plastics from Entsorga, Cologne, Germany. The technology is to convert waste plastics into liquid fuels by depolymerization or to prepare oil fractions without pressurization during production.
The T-Technoloy process is an alternative to waste plastic granulation or incineration because the process converts the waste plastic back to its original form, that is, gas-distilled hydrocarbons containing C1-C4 chain lengths. Such hydrocarbons can be further processed. Refineries process or use fuel oil fractions for home heating.
2) Decomposing Waste Plastic Bottles with Microwave Oven Japan has recently developed a new method of recycling waste plastic bottles using microwave ovens. This method is the rapid decomposition of plastic bottles into raw materials, its energy consumption is only 1/4 of the traditional plastic bottle decomposition method. The specific method is: first cut the plastic bottle into pieces with a machine, add NaOH and alcohol substances to the chips, and then heat for 1.5 minutes in a microwave oven. Under the influence of microwaves, plastic bottle fragments can be decomposed into ethylene glycol and terephthalic acid. Ethylene glycol can be used to produce polyester fibers and antifreeze. High purity terephthalic acid can be used to make paints.
3) Decomposition and Recovery of Plastic Raw Materials by Supercritical Water The Japanese Laid-Open Patent Publication reported the use of supercritical water for the degradation and recovery processes of waste plastics (PE, PP), and proposes a device diagram and reaction flow chart of the pilot plant. The reaction temperature is 400 to 600°C, the reaction pressure is 25 MPa, and the reaction time is 10 minutes or less, and an oil ratio of 90% or more can be obtained.
Decomposition experiments of PC with supercritical water showed that the purity of bisphenol-A as a decomposed product reached 95%, and the remaining 5% was a phenol used as a PC terminal blocking agent. Therefore, the purity of the raw material for this reaction was recovered. high.
(b) Completely degradable plastics 1. Development and application of fully degradable plastics 1) Starch Thermoplastic starch is used in the manufacture of films and garbage bags, such as Czech Ecofol films and Italian Bioflex films.
Starch foamed plastic balls, ropes, strips, nets, sheets, vacuum molded containers, and trays are mainly used as substitutes for polystyrene foam and have been commercialized. Such as the United States, Amylun, NationalStarch & Chemical, Daniels, Novon, International; Biotec in Western Europe, Storopack, Sunstarke, Novamont, PaperFoam; Asia, JapanCorn. Starch, Sakai Chemical, Chisso/Novon and other companies have already mass-produced, among which Japan Green Earth has developed a starch resin with better performance, the trade name is “green starchâ€; the United States Champion International has made starch fiber with excellent mechanical properties. .
2) Cellulose Derivatives Japan, Russia, and the United States have carried out research on biodegradable plastics mainly composed of cellulose derivatives. The Shikoku Industrial Technology Laboratory, the Japan Physical and Chemical Research Institute, and Nishikawa Rubber Industries Co., Ltd. obtained cast films, facial tissues, and foamed materials, respectively.
3) Polylactic acid polylactic acid (PLA)
It uses corn, wheat, cassava and other starches as raw materials to be decomposed by enzymes to obtain glucose-sulfured glucose. After fermentation by lactic acid bacteria, it is transformed into lactic acid and finally lactic acid is chemically synthesized to obtain high-purity polymers. At present, the synthesis of PLA has two main methods: 1 direct polycondensation; 2 lactide ring-opening polymerization. The direct polymerization process is simple, the amount of chemical materials and reagents is small, but the polymer molecular weight is still low. The lactide ring-opening polymerization method is an indirect method, and the synthesis process uses lactic acid as a raw material to prepare lactide first in the presence of an initiator or a catalyst, and then to prepare PLA and its copolymer by ring-opening polymerization of lactide in the presence of a catalyst. . This method can obtain high molecular weight (700,000 - 1 million) PLA, but the process is complicated and the cost is high. At present, the United States, Germany, Japan, Finland, and the Netherlands have all achieved the industrialization of polylactic acid. The United States Cargill-Dow Company, with an annual output of 140,000 tons, uses polylactic acid products in packaging, textiles, and disposable plastic products.
In 1998 Germany realized the commercialization of PLA boxes. In Japan Unigika, Zhongfang, Dongli, Mitsui Chemicals and other companies have annual production of less than 10,000 tons, of which Toray is working with Cargill Dow in spinning development. In addition, Denmark, Canada, South Korea and other countries are also conducting polylactic acid industrialization research. The domestic Hisun Group has realized the industrialization of polylactic acid.
4) Poly-β-hydroxyalkanoates (PHAS)
PHAS has two preparation methods: 1 It uses starch as raw material, and it is produced by bio-fermentation (such as Alcaligenes eutropha) technology; 2 It uses alkanes as carbon source, and it is prepared by changing the control conditions of carbon source and Pseudomonas culture process. Different structure of PHAS.
Austrian Linz Chemical Group and Austrian Bio-Technology Co., Ltd. use alkali-producing bacilli to use molasses as raw material and produce 20 tons of PHB per year. ICI, an original British imperial chemical company, commercialized PHB and PHBV with the product name "BIOPOL". The Brazilian company PHBIndustralS/A has an annual output of 50 tons. Japan's Mitsubishi Gas Chemical Company has an annual output of 10 tons. Japan Showa Polyester produces aliphatic polyester PHB (polybutylene succinate) for shopping bags, agricultural films, plates, etc. After modification of isocyanate materials, it can improve the material's rigidity and thermoplasticity. Domestic Tianan Biomaterials Co., Ltd. PHBV production capacity of 1,000 tons / year.
5) Copolyesters Japan's Mitsubishi Gas Chemicals (MGC) produces carbonated polyester (PEC), which has a melting point of 110°C and performs similarly to PP homopolymers and is used by Sony for tape packaging. The aliphatic aromatic random copolyester (Ecoflex) manufactured by BASF, Germany, does not need to be dried prior to processing. It has good processing melt stability below 230°C, good tensile properties, and a film thickness of 10 μm can be obtained. Good barrier properties for oxygen and water vapor, excellent price performance ratio.
Inner Mongolia Mengxi Company was established at the end of 2002 to build an annual production capacity of 3,000 tons of carbon dioxide and propylene oxide copolymer (PPC) synthetic production line, is currently mainly used in packaging and medical materials.
2. Completely degradable plastic recycling 4. Development trend of environmentally friendly plastics (I) Production technology innovation 1. Recycled plastic recycling technology 1) Reduction/energy-saving technologies such as new micro-hole forming technology, auxiliary forming technology, and morphological control Technology, low-pressure molding technology, composite material molding technology.
2) homogenization/homogenization/ontology technologies such as high-performance materials, such as hole compatilizers, filling modification, dynamic cross-linking, nano-composite, snow, plastic assembly technology.
3) Recycled plastic recycling sorting technologies such as electrostatic separation of waste plastics, electromagnetic separation systems, X-ray processing separation, IR sorting technology.
4) Thermal cracking and energy recovery engineering technology and management system 5) High-performance recycling technology of recycled plastics 2. Bio-polymer synthesis modification technology of bio-materials 1) Improvement of gene engineering strains and synthetic processes 2) Common with other bio-degradable materials Blending improves performance such as polycaprolactone (PCL), ethylene-vinyl acetate copolymer, poly-4-vinylphenol, poly-ε-caprolactone, poly-3-hydroxybutyrate, and the like.
3) Fill modification such as hydroxyapatite (31% increase in mechanical strength of PLA/HA composite compared to unmodified composite), β-tricalcium phosphate (β-TCP snow, montmorillonite clay, layered silicate) Modified PLA.
4) Plasticization Modification All kinds of low molecular weight polymers, plasticizers, and high molecular weight PEG plasticized modified PLA, PHBV, PPC and so on. Replacement of commonly used alcohol plasticizers with amine-based compounds such as urea, thiourea, and guanidine hydrochloride can promote the gelation of starch and effectively inhibit starch aging and brittleness.
5) Cross-linked modified potato starch is modified by etherification. Water, PVA, glycerol, and other additives are added to the modified starch to prepare an all-starch thermoplastic film. Using glyoxal as a cross-linking agent, polyethylene glycol as an assistant, and modified starch as the main raw material, an all-starch film can be prepared.
6) The polyurethane and chitosan prepared from the composite layer modified renewable materials are used to modify the composite layer of starch. Polyester-starch-polyester composite layer has good water resistance. Its products can be used for the controlled release of food packaging or drugs, insecticides and herbicides.
7) Grafting, copolymerization modification, such as PLLA-PCL-PLLA, PLA-co-PCL copolymer compatibilizers, these compatibilizers can promote the dispersion of PCL in the PLA matrix, and improve the mechanical properties of the blended film. .
3. Production technology of environmentally friendly plastic additives 1) Synthesis and application technology of non-toxic plastic additives For example, fatty acid esters, epoxy esters, polyethylene glycols, alkanes, higher polyols, aliphatic amides, Polysaccharides and amino acids are syntheses of basic structural units such as oligomers, polymers, decomposition residues, and salts formed with metals such as zinc, calcium, magnesium, titanium tin, and aluminum.
2) The synthesis and application technology of high-efficiency, non-toxic composite plastic additives such as the matching technology between various types of additives.
3) Non-toxic natural mineral filler application technologies such as mineral ultrafine powder, processing technology and application technology.
4. Molding and processing technologies for environmentally friendly plastic products 1) New processing technologies for forming water-soluble polymers such as PVAL, starch, and chitosan.
2) A new type of fully biodegradable plastic molding technology such as PLA flexible film molding, PLA reinforcement and toughening injection molding/extrusion molding technology, PHAS reinforced modified product molding processing, and modified aliphatic aliphatic polycarbonate plastic products.
3) Lightweight natural fiber filled composite molding technologies such as straw, starch, and shell powder filled with environmentally friendly plastic microfoam molding technology.
4) Molding technology for high-performance recycled plastic products such as co-injection, co-extrusion, and stretch-oriented molding of composite products.
5) Dedicated/special environment-friendly plastic product molding equipment machinery (2) Establishment of a sound evaluation and supervision system 1. Classification criteria for plastics such as "Degradation plastic sheet definition, classification, marking and degradation performance requirements", "Biodegradable plastic sheet definition , Signs, and Biodegradability Requirements, Definitions, Signatures, and Compostability Requirements for Compostable Plastic Sheets.
2. Labeling of environmentally friendly plastic products such as "Marking and Marking of Plastic Products".
3. Test methods and technical standards such as "Determination of final aerobic biodegradability of materials in soil -- Method for determination of oxygen demand or determination of released carbon dioxide in closed respirometer", "In the definition of compost pilot test conditions "Determination of disintegration capacity of lower materials" and "Determination of final aerobic biodegradability of materials under controlled composting conditions--Method for determination of released carbon dioxide".
4. Regulatory, institutionalized, and procedural regulations for recycling, such as Solid Waste Disposal Law, Resource Recovery Law, Pollution Prevention Law, Basic Law for Promoting the Establishment of Circular Society, and Solid Waste Management and Public Cleaning Law "," "Promote the effective use of resources law", "Promote containers and packaging classification recovery law", "Household appliances recycling law", "Building and materials recycling law", "Food recycling law", "Green procurement law."
(c) National industrial policy orientation and promotion of the establishment of a complete recycling-oriented society's material production system For example, Japan has comprehensively formulated the industrial science and technology development plan for a recycling-oriented society, including the scientific and technological development plans and supporting operating systems/regulations in various related fields. We propose a strategy for economic development from technology-building to environment-building, and the Ministry of Agriculture, Forestry and Fisheries has formulated Japan's strategy for biological substances.
China has also included related research projects in the “Ninth Five-year Planâ€, “Tenth Five-year Planâ€, “863â€, and “Eleventh Five-Year Plan†programs, and formulated the “Renewable Energy Law (Draft)†and “Solid Waste Law (Revised). Laws such as ")" smoked the "science, technology, humanities, and green" Olympic project.
(D) Government, production enterprises, consumer groups, environmental awareness, responsibilities, and obligations to strengthen, ensure the increasingly prosperous market for environmentally friendly plastics. 1. The government promulgates laws and regulations to prohibit the use of unfriendly plastics, such as taxation policy. (The Hong Kong government proposes to levy tax on plastic bags. ) Smoke banned production/sales policy smoked encouraging environmentally friendly plastic products applications. It is not easy to recycle ultra-thin POF film.
2. Production companies take on social responsibility, smoke recovery, use of products, smoke, promote environmental friendly plastic applications and technological developments. For example, Microsoft's best-selling GPS, Microsoft Map Navigation Software 2007 uses recycled waste packaging, and performs PLA hard and soft packaging and sheets. Apply the experiment. Automobiles, home appliances and furniture manufacturers recycle waste.
China's recyclable plastic waste is about 4 to 5 million tons per year, and about 2 million tons of waste plastics are actually recycled.
The harm caused by plastics to the environment is mainly in the following four aspects: 1. The lack of petrochemical resources.
2. The plastic processing consumes a lot of energy.
3. The production, use, by-products, emissions, and waste of plastic additives are harmful to the human body and the environment.
4, plastic products are not easy to break down and not easy to recycle, plastic waste pollution of the environment as hazardous waste.
Second, the concept of environmentally friendly plastics 1. Define plastics that will not cause irreversible damage to the environment during production, use, or disposal. That is to say, they are cost-effective, easy to recycle, use energy-saving and environmentally friendly methods, and be used in the environment. The plastic materials that are completely degraded and harmless to the natural environment, human beings, or biosphere are relatively environmentally friendly plastics.
2. Environment-friendly plastics classification 1) Recycled plastics â– Reusable plastics such as POF â– Recyclable plastics such as PET, PVAL2) Biodegradable â– Biodegradable plastics (natural polymers and modified substances) such as starch, natural cellulose Derivatives and their filled modified POF.
Fully biodegradable plastics (biotransformation synthetic modifiers) such as starch-based, aliphatic-aromatic copolyesters, polyhydroxyalkanoates, PLA.
3. Characteristics of environment-friendly plastics 1) Cleanliness can be produced by clean production, and plastic materials that can be routinely produced can be produced without the need of adding a small amount of additives.
2) Reduced, energy-saving plastic products that use homogeneous, homogenous, light-weight and bulk products or production methods that increase the availability of plastic raw materials and reduce processing energy consumption, such as gas-assisted molding, micro-hole forming, and half Melt molding, vibration molding technology.
3) Resource-based biomass resources - The use of natural polymers and plastics produced by biotransformation to obtain organic intermediates and synthetic polymer materials. Starch, straw composites, poly-β-hydroxyalkanoates (PHAS), polylactic acid (PLA).
4) Harmlessly degradable plastic products, biodegradable and hydrolyzed polymer materials such as PLA, PCL, polybutylene succinate PBS snow, PVAL.
III. Development and application status of environmentally friendly plastics at home and abroad (1) Recycled plastics 1 Development and application of recycled plastics 1) Industrial development of wood/plastic composite materials According to the research report of the United States PricinpiaPartmers Consulting Company in 2003, Europe and North America are currently the world's plastics The largest area of ​​wood material market is about 600,000 tons, of which the North American market accounts for about 85%. It is predicted that by 2010, wood/plastic composite materials in Europe and North America will increase by 14% and 18% respectively.
Wood/plastic composite materials used in: wall panels, partitions, decorative panels, building templates, highway noise separators, beach boards, dock platform boards, railway sleepers, packaging and logistics combination trays, storage racks, fences, Handrails, outdoor terraces and other transportation, construction, and public facilities.
It is predicted that by 2010, the largest application of wood/plastic composite foams is the introduction of building products. High-performance, lightweight wood/plastic composite foams will find great application in automotive interiors, doors and windows. China will continue to develop at an average annual growth rate of over 50%. The output and output value of China's wood/plastic composite materials and products will eventually form a new industrial system with a production value of 10 million tons/year or 70 billion yuan.
2) PEP bottle recycling technology Each year, the global consumption of beverage bottle waste is more than 10 million tons, and its output and consumption increase at a rate of 10% to 19% year by year. The consumption of polyester bottles in China was 1.78 million tons in 2005, and it is estimated that its recycling rate is at least 90%.
Polyester waste bottle recycling methods include physical and chemical methods. The vast majority of mechanical waste recycling is used to produce fiber, and some are used in plastic processing (non-food packaging materials and products). Chemical alcoholysis, alkaline hydrolysis, or hydrolysis of waste to produce terephthalic acid, ethylene glycol, and acetaldehyde and other substances. Physical recovery of waste bottles is the use of solid-phase polycondensation technology to improve the performance of waste, and then used for bottle filling beverages.
GE Plastics has successfully developed PBT resins and PC/PBT blends from used PET bottles. The target of this type of resin application is the automotive industry, and 80% of its output can be produced from waste waste bottles.
3) Production of high-density bricks from waste plastics Mexico will collect plastic bottles filled with shampoos, wine, mineral water, and beverages, and use molding technology to produce high-density bricks that are shock-resistant and have a long life compared to ordinary bricks. With its advantages of light weight and low cost, it can save 30% of construction costs.
4) Waste plastics to create advanced new packaging materials New Zealand has successfully synthesized waste plastic polyethylene milk bottles and waste coke bottles into a new plastic. This new type of plastic is harder than waste, and its oxygen barrier effect is increased by 2-3 times. It is very suitable for food packaging materials. With the addition of suitable additives, the electromagnetic shielding performance of the plastic is greatly improved, making it an ideal packaging material for electronic products. This new plastic can be recycled for several uses without degrading performance.
5) Classification of plastic parts in durable consumer goods 2. Recycling plastics recycling and decomposing technology 1) Pyrolysis into liquid fuels A. Conversion of waste polyolefins into aromatic hydrocarbons Kawashima Harima Heavy Industries has recently developed polyolefin plastics into benzene, The yields of toluene and xylene were: benzene 15%, toluene 20%, and xylene 15%. The remaining components are less than 10% ethylbenzene, about 30% C1 to C4 hydrocarbon gases, and waxes and cokes.
B. Depolymerization of Waste Plastics into Liquid Fuels Tokar has developed a new T-Technoloy process and applied it to the recycling of waste plastics from Entsorga, Cologne, Germany. The technology is to convert waste plastics into liquid fuels by depolymerization or to prepare oil fractions without pressurization during production.
The T-Technoloy process is an alternative to waste plastic granulation or incineration because the process converts the waste plastic back to its original form, that is, gas-distilled hydrocarbons containing C1-C4 chain lengths. Such hydrocarbons can be further processed. Refineries process or use fuel oil fractions for home heating.
2) Decomposing Waste Plastic Bottles with Microwave Oven Japan has recently developed a new method of recycling waste plastic bottles using microwave ovens. This method is the rapid decomposition of plastic bottles into raw materials, its energy consumption is only 1/4 of the traditional plastic bottle decomposition method. The specific method is: first cut the plastic bottle into pieces with a machine, add NaOH and alcohol substances to the chips, and then heat for 1.5 minutes in a microwave oven. Under the influence of microwaves, plastic bottle fragments can be decomposed into ethylene glycol and terephthalic acid. Ethylene glycol can be used to produce polyester fibers and antifreeze. High purity terephthalic acid can be used to make paints.
3) Decomposition and Recovery of Plastic Raw Materials by Supercritical Water The Japanese Laid-Open Patent Publication reported the use of supercritical water for the degradation and recovery processes of waste plastics (PE, PP), and proposes a device diagram and reaction flow chart of the pilot plant. The reaction temperature is 400 to 600°C, the reaction pressure is 25 MPa, and the reaction time is 10 minutes or less, and an oil ratio of 90% or more can be obtained.
Decomposition experiments of PC with supercritical water showed that the purity of bisphenol-A as a decomposed product reached 95%, and the remaining 5% was a phenol used as a PC terminal blocking agent. Therefore, the purity of the raw material for this reaction was recovered. high.
(b) Completely degradable plastics 1. Development and application of fully degradable plastics 1) Starch Thermoplastic starch is used in the manufacture of films and garbage bags, such as Czech Ecofol films and Italian Bioflex films.
Starch foamed plastic balls, ropes, strips, nets, sheets, vacuum molded containers, and trays are mainly used as substitutes for polystyrene foam and have been commercialized. Such as the United States, Amylun, NationalStarch & Chemical, Daniels, Novon, International; Biotec in Western Europe, Storopack, Sunstarke, Novamont, PaperFoam; Asia, JapanCorn. Starch, Sakai Chemical, Chisso/Novon and other companies have already mass-produced, among which Japan Green Earth has developed a starch resin with better performance, the trade name is “green starchâ€; the United States Champion International has made starch fiber with excellent mechanical properties. .
2) Cellulose Derivatives Japan, Russia, and the United States have carried out research on biodegradable plastics mainly composed of cellulose derivatives. The Shikoku Industrial Technology Laboratory, the Japan Physical and Chemical Research Institute, and Nishikawa Rubber Industries Co., Ltd. obtained cast films, facial tissues, and foamed materials, respectively.
3) Polylactic acid polylactic acid (PLA)
It uses corn, wheat, cassava and other starches as raw materials to be decomposed by enzymes to obtain glucose-sulfured glucose. After fermentation by lactic acid bacteria, it is transformed into lactic acid and finally lactic acid is chemically synthesized to obtain high-purity polymers. At present, the synthesis of PLA has two main methods: 1 direct polycondensation; 2 lactide ring-opening polymerization. The direct polymerization process is simple, the amount of chemical materials and reagents is small, but the polymer molecular weight is still low. The lactide ring-opening polymerization method is an indirect method, and the synthesis process uses lactic acid as a raw material to prepare lactide first in the presence of an initiator or a catalyst, and then to prepare PLA and its copolymer by ring-opening polymerization of lactide in the presence of a catalyst. . This method can obtain high molecular weight (700,000 - 1 million) PLA, but the process is complicated and the cost is high. At present, the United States, Germany, Japan, Finland, and the Netherlands have all achieved the industrialization of polylactic acid. The United States Cargill-Dow Company, with an annual output of 140,000 tons, uses polylactic acid products in packaging, textiles, and disposable plastic products.
In 1998 Germany realized the commercialization of PLA boxes. In Japan Unigika, Zhongfang, Dongli, Mitsui Chemicals and other companies have annual production of less than 10,000 tons, of which Toray is working with Cargill Dow in spinning development. In addition, Denmark, Canada, South Korea and other countries are also conducting polylactic acid industrialization research. The domestic Hisun Group has realized the industrialization of polylactic acid.
4) Poly-β-hydroxyalkanoates (PHAS)
PHAS has two preparation methods: 1 It uses starch as raw material, and it is produced by bio-fermentation (such as Alcaligenes eutropha) technology; 2 It uses alkanes as carbon source, and it is prepared by changing the control conditions of carbon source and Pseudomonas culture process. Different structure of PHAS.
Austrian Linz Chemical Group and Austrian Bio-Technology Co., Ltd. use alkali-producing bacilli to use molasses as raw material and produce 20 tons of PHB per year. ICI, an original British imperial chemical company, commercialized PHB and PHBV with the product name "BIOPOL". The Brazilian company PHBIndustralS/A has an annual output of 50 tons. Japan's Mitsubishi Gas Chemical Company has an annual output of 10 tons. Japan Showa Polyester produces aliphatic polyester PHB (polybutylene succinate) for shopping bags, agricultural films, plates, etc. After modification of isocyanate materials, it can improve the material's rigidity and thermoplasticity. Domestic Tianan Biomaterials Co., Ltd. PHBV production capacity of 1,000 tons / year.
5) Copolyesters Japan's Mitsubishi Gas Chemicals (MGC) produces carbonated polyester (PEC), which has a melting point of 110°C and performs similarly to PP homopolymers and is used by Sony for tape packaging. The aliphatic aromatic random copolyester (Ecoflex) manufactured by BASF, Germany, does not need to be dried prior to processing. It has good processing melt stability below 230°C, good tensile properties, and a film thickness of 10 μm can be obtained. Good barrier properties for oxygen and water vapor, excellent price performance ratio.
Inner Mongolia Mengxi Company was established at the end of 2002 to build an annual production capacity of 3,000 tons of carbon dioxide and propylene oxide copolymer (PPC) synthetic production line, is currently mainly used in packaging and medical materials.
2. Completely degradable plastic recycling 4. Development trend of environmentally friendly plastics (I) Production technology innovation 1. Recycled plastic recycling technology 1) Reduction/energy-saving technologies such as new micro-hole forming technology, auxiliary forming technology, and morphological control Technology, low-pressure molding technology, composite material molding technology.
2) homogenization/homogenization/ontology technologies such as high-performance materials, such as hole compatilizers, filling modification, dynamic cross-linking, nano-composite, snow, plastic assembly technology.
3) Recycled plastic recycling sorting technologies such as electrostatic separation of waste plastics, electromagnetic separation systems, X-ray processing separation, IR sorting technology.
4) Thermal cracking and energy recovery engineering technology and management system 5) High-performance recycling technology of recycled plastics 2. Bio-polymer synthesis modification technology of bio-materials 1) Improvement of gene engineering strains and synthetic processes 2) Common with other bio-degradable materials Blending improves performance such as polycaprolactone (PCL), ethylene-vinyl acetate copolymer, poly-4-vinylphenol, poly-ε-caprolactone, poly-3-hydroxybutyrate, and the like.
3) Fill modification such as hydroxyapatite (31% increase in mechanical strength of PLA/HA composite compared to unmodified composite), β-tricalcium phosphate (β-TCP snow, montmorillonite clay, layered silicate) Modified PLA.
4) Plasticization Modification All kinds of low molecular weight polymers, plasticizers, and high molecular weight PEG plasticized modified PLA, PHBV, PPC and so on. Replacement of commonly used alcohol plasticizers with amine-based compounds such as urea, thiourea, and guanidine hydrochloride can promote the gelation of starch and effectively inhibit starch aging and brittleness.
5) Cross-linked modified potato starch is modified by etherification. Water, PVA, glycerol, and other additives are added to the modified starch to prepare an all-starch thermoplastic film. Using glyoxal as a cross-linking agent, polyethylene glycol as an assistant, and modified starch as the main raw material, an all-starch film can be prepared.
6) The polyurethane and chitosan prepared from the composite layer modified renewable materials are used to modify the composite layer of starch. Polyester-starch-polyester composite layer has good water resistance. Its products can be used for the controlled release of food packaging or drugs, insecticides and herbicides.
7) Grafting, copolymerization modification, such as PLLA-PCL-PLLA, PLA-co-PCL copolymer compatibilizers, these compatibilizers can promote the dispersion of PCL in the PLA matrix, and improve the mechanical properties of the blended film. .
3. Production technology of environmentally friendly plastic additives 1) Synthesis and application technology of non-toxic plastic additives For example, fatty acid esters, epoxy esters, polyethylene glycols, alkanes, higher polyols, aliphatic amides, Polysaccharides and amino acids are syntheses of basic structural units such as oligomers, polymers, decomposition residues, and salts formed with metals such as zinc, calcium, magnesium, titanium tin, and aluminum.
2) The synthesis and application technology of high-efficiency, non-toxic composite plastic additives such as the matching technology between various types of additives.
3) Non-toxic natural mineral filler application technologies such as mineral ultrafine powder, processing technology and application technology.
4. Molding and processing technologies for environmentally friendly plastic products 1) New processing technologies for forming water-soluble polymers such as PVAL, starch, and chitosan.
2) A new type of fully biodegradable plastic molding technology such as PLA flexible film molding, PLA reinforcement and toughening injection molding/extrusion molding technology, PHAS reinforced modified product molding processing, and modified aliphatic aliphatic polycarbonate plastic products.
3) Lightweight natural fiber filled composite molding technologies such as straw, starch, and shell powder filled with environmentally friendly plastic microfoam molding technology.
4) Molding technology for high-performance recycled plastic products such as co-injection, co-extrusion, and stretch-oriented molding of composite products.
5) Dedicated/special environment-friendly plastic product molding equipment machinery (2) Establishment of a sound evaluation and supervision system 1. Classification criteria for plastics such as "Degradation plastic sheet definition, classification, marking and degradation performance requirements", "Biodegradable plastic sheet definition , Signs, and Biodegradability Requirements, Definitions, Signatures, and Compostability Requirements for Compostable Plastic Sheets.
2. Labeling of environmentally friendly plastic products such as "Marking and Marking of Plastic Products".
3. Test methods and technical standards such as "Determination of final aerobic biodegradability of materials in soil -- Method for determination of oxygen demand or determination of released carbon dioxide in closed respirometer", "In the definition of compost pilot test conditions "Determination of disintegration capacity of lower materials" and "Determination of final aerobic biodegradability of materials under controlled composting conditions--Method for determination of released carbon dioxide".
4. Regulatory, institutionalized, and procedural regulations for recycling, such as Solid Waste Disposal Law, Resource Recovery Law, Pollution Prevention Law, Basic Law for Promoting the Establishment of Circular Society, and Solid Waste Management and Public Cleaning Law "," "Promote the effective use of resources law", "Promote containers and packaging classification recovery law", "Household appliances recycling law", "Building and materials recycling law", "Food recycling law", "Green procurement law."
(c) National industrial policy orientation and promotion of the establishment of a complete recycling-oriented society's material production system For example, Japan has comprehensively formulated the industrial science and technology development plan for a recycling-oriented society, including the scientific and technological development plans and supporting operating systems/regulations in various related fields. We propose a strategy for economic development from technology-building to environment-building, and the Ministry of Agriculture, Forestry and Fisheries has formulated Japan's strategy for biological substances.
China has also included related research projects in the “Ninth Five-year Planâ€, “Tenth Five-year Planâ€, “863â€, and “Eleventh Five-Year Plan†programs, and formulated the “Renewable Energy Law (Draft)†and “Solid Waste Law (Revised). Laws such as ")" smoked the "science, technology, humanities, and green" Olympic project.
(D) Government, production enterprises, consumer groups, environmental awareness, responsibilities, and obligations to strengthen, ensure the increasingly prosperous market for environmentally friendly plastics. 1. The government promulgates laws and regulations to prohibit the use of unfriendly plastics, such as taxation policy. (The Hong Kong government proposes to levy tax on plastic bags. ) Smoke banned production/sales policy smoked encouraging environmentally friendly plastic products applications. It is not easy to recycle ultra-thin POF film.
2. Production companies take on social responsibility, smoke recovery, use of products, smoke, promote environmental friendly plastic applications and technological developments. For example, Microsoft's best-selling GPS, Microsoft Map Navigation Software 2007 uses recycled waste packaging, and performs PLA hard and soft packaging and sheets. Apply the experiment. Automobiles, home appliances and furniture manufacturers recycle waste.
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