Synthetic plastics have made tremendous contributions to promoting industrial development and improving people's living standards. In the early days of the development of the plastics industry, the chemical stability of synthetic materials is one of the most concerned and important research topics. After several decades, its stability has been well resolved. Dramatically, its stability has become an important reason hindering its further development. “Agricultural film†is a good example. Because it is difficult to be biodegraded, it can only be used once. The easiest way to deal with it is to burn it. This not only wastes resources but also causes air pollution. The recycling and utilization of waste plastic products has become a worldwide issue. Traditional landfill and incineration processes are being replaced by reuse, degradation or decomposition processes. The recycling of waste plastic products not only protects the environment, saves energy, but also has good economics. There are three concepts in the industry for the recycling and utilization of plastic products, namely direct use, conversion, and incineration or biodegradation. Conversion utilization As the name suggests, it is used for other purposes. Both chemical and physical methods are included. Chemical methods can be divided into two types. The first method is to convert the polymer into a small molecule compound or a simple compound by utilizing the chemical properties of the polymer. For example, the polyester can be converted to a monomer or a small molecule compound by hydrolysis, alcoholysis or aminolysis. The hydrolysis reaction is a reverse reaction of the polyester synthesis reaction, and can be made into terephthalic acid and ethylene glycol (polyester synthesis raw material monomer); methanol alcoholysis can obtain methyl terephthalate and ethylene glycol; The product to be solved is bishydroxyethyl terephthalate; the propylene glycol alcoholysis produces oligomers for the synthesis of unsaturated polyesters (for paints or inks) and alkyd resins. Another method is to use the flammability of plastics to generate heat energy after incineration. These two methods have their own advantages and disadvantages. The chemical decomposition method has higher utilization rate of resources, but the process is complicated and the cost is high, thus affecting the recycling of plastic products. Exhaust gas generated by incineration, such as chlorine-containing gas produced by burning PVC (polyvinyl chloride film), is a component of acid rain. In addition, many plastics generate exhaust gas due to incomplete combustion, which is harmful to the environment and human health. There are trends in the way to be eliminated. The use of physical conversion is similar to direct utilization. The difference is that the latter is used by the manufacturer itself, and the former is used by other manufacturers. The process is also crushing-granulation-extrusion (stretching) or injection molding, etc., if necessary, adding other articles. Below are some examples of successful physical conversion of polystyrene foam. Sound insulation material After the waste foam is pulverized, it is heated by infrared irradiation to reduce its volume to less than 1/20; and then mixed with special cement to make a "rice sugar"-like building material. This building material has an average of 60% noise reduction and 90% noise suppression for certain frequencies. This material is now being used for conversion As the name suggests, it is used for other purposes. Both chemical and physical methods are included. The walls and ceilings of the soundproofing of the power station. Manufacture of lightweight roofing insulation The waste expanded polystyrene is pulverized, added with expanded perlite and cement, mortar, stirred and mixed evenly, cured on the roof for 3 days, naturally dried, and then smoothed with a cement mortar into a lightweight concrete insulation layer. The material produced by the method has low production cost, good heat preservation property, and the house is warm in winter and cool in summer. The waste expanded polystyrene is washed, pulverized to a particle size of 0.1-0.5 cm, and 425 cement paste is added, and the volume ratio of the two is 2-3: 1, add 1-3% of the early strength agent (inorganic alkali), stir with water to form a slurry, add rosin soap foaming agent, then stir into a slurry, into the mold, demoulding after 1 hour, water conservation 7 Made of 10cm thick sheet, its heat transfer coefficient and compressive strength are good, and the thermal insulation performance can reach the insulation effect of clay brick wall thickness of 95cm. When using the roof, apply a layer of cement mortar on the board, use water to maintain, and then use asphalt felt to make waterproof layer. The waste expanded polystyrene material is made into a 5% solution with a solvent, and the pulverized corn cob plant fiber is added and mixed and pressed. Manufacturing waterproof membrane The waste expanded polystyrene is washed, dried, and dissolved in an inexpensive phenol or chlorohydrocarbon residue. The toughening agent and the film-forming anti-seepage anti-wear agent are added to form a viscose. After being blown or applied to the surface of the glass cloth, it is dried into a waterproof membrane for roof waterproofing or pipelines, and the solvent can be recycled after being cooled. Manufacture of metal, wood doors and windows and glass sealants Add 50 kg of waste expanded polystyrene, 40 kg of solvent oil No. 200, 50 kg of xylene in a dissolution tank, stir to dissolve and remove impurities, and obtain a transparent polystyrene rubber. Add 13kSl788 industrial grade polyvinyl alcohol to another dissolution tank, add 80kg of water, and heat to dissolve at 30-90 °C. Add 1kg of dibutyl phthalate and surfactant octylphenol polyoxyethylene ether slightly, and add a proper amount of filler bentonite to form a paste. The product contains polar substances, which can increase the bonding strength and improve the emulsifying properties. Both polyvinyl alcohol and bentonite can be uniformly dispersed in the paste. The finished product has fast drying, good performance, and excellent acid and weather resistance. Used as asphalt enhancer Adding waste expanded polystyrene granules to the molten asphalt can enhance heat and water resistance and can be used as roofing and road building materials. Manufacturing anti-seepage trapping agent It is produced by the hot melt process using waste water polystyrene as raw material and a small amount of plasticizer. The product is fast in plasticization, fast in drying, and has the characteristics of good sealing performance, strong adhesion, acid and alkali resistance and anti-aging. Its waterproof and anti-corrosion performance greatly exceeds the commonly used plastic ointment and asphalt grease, and its service life can reach more than 20 years. Manufacturing multifunctional resin glue The multifunctional resin glue produced by waste polystyrene foam has the characteristics of good adhesion, high gloss, strong impact resistance, acid and alkali resistance, etc., and is used for producing various FRP products, which can greatly reduce the production cost; It can produce waterproof coatings, satin paints, furniture putty glue and other products. With rust antirust paint The rust-proof anti-rust paint produced by waste polystyrene foam has low cost and can be directly applied to the surface of steel with certain rust, has the triple function of anti-penetration, anti-rust and anti-corrosion, and can also be used for surface paint of civil furniture. Direct use The processing of plastic products is mainly a physical process, that is, the addition of an auxiliary or masterbatch, and is basically a physical mixing process. After the plastic chips or pellets are heated and melted, the injection molded product, the injection blow molded product or the extrusion blown film or the extruded cast sheet is stretched into a film. Examples of injection molded products are foam packaging materials (blocks). Examples of injection molded blow molded products are various plastic packaging bottles. Examples of extrusion blow molding into films are multilayer coextruded film products such as heat shrinkable film, cling film, and extrusion. Examples of the stretched film of the cast piece are a biaxially oriented polypropylene film BOPP and a biaxially stretched polyester film BOPET. Since the changes in the materials in the above process are all physical changes, the chemical structure is unchanged, which provides convenience for the application of the trim. Therefore, in the plastic product manufacturing plant, the scraps in the production are generally crushed, extruded granulated or melted, extruded and granulated, and put back into the production line for further use. Because of this, crushers and granulators are essential equipment in the plastics industry. However, there is a limitation to this method, that is, the plastic product should be a single component or the physical properties of the components are not much different, and the secondary physical processing is not affected. For example, according to a US company, EVOH is a PET beer bottle made of a sandwich. The barrier effect can reach the level of glass bottles and can be completely recycled. However, for most multi-layer composite membranes or multi-layer co-extruded membranes, the physical and chemical properties of the various layers are largely different and cannot be directly recycled. Problem and solution Whether it is chemical methods or physical methods, there is a major difficulty, that is, the recycling of waste plastics is mixed, it is difficult to identify the classification, on the other hand, it is particularly dirty (disposable polystyrene lunch boxes), cleaning is very difficult, operation The cost is high, so the enthusiasm of the manufacturers is not high. There are two main solutions at present: limiting the production of multi-component plastic products and improving the level of classified collection and tillering. For example, in order to promote the recycling of resources, the “Plastic Bottle Recycling Promotion Conferenceâ€, which is composed of Japanese beverage manufacturers and plastic bottle manufacturers, recently decided to stop production of colored plastic bottles that hinder recycling. The used plastic bottles will be collected according to the methods stipulated in the "Container Packaging Recycling Law", and then crushed in the factory, and then made into fiber products, hangers, garbage cans, and the like. In the past, in order to protect beverages such as juice from the bottle from ultraviolet rays, manufacturers use blue and green plastic bottles. However, in the case of recycling, if colored plastic bottles are mixed, not only the quality of the recycled products will be degraded, but also the manual processing is very troublesome. After all the transparent bottles were used, the solution to the ultraviolet irradiation was to cover all the transparent bottles with labels, and the needle holes on the label were left for easy peeling. Caps made of metal such as aluminum will also be replaced by plastics made of the same material as the bottle. In addition, tillering is an important factor in determining the economics of material reuse. At present, foreign branching technology has developed rapidly, and many automated branching lines have been put into use, which can be used to accurately classify different types of materials. The biggest difficulty comes from composite plastic products. Biodegradable Since plastic products are not easily aged, they are difficult to be decomposed by microorganisms, causing so-called white pollution. Instead of passively dealing with it, it is better to think of it from the source, and because of this, the plastics industry attaches great importance to the research and development of biodegradable plastics. At present, there are few varieties that are satisfactory in both performance and biodegradability. There is still a long way to go to truly achieve industrialization. Led Par Light,Washer Par Light,Led Mini Party Light,Led Flat Par Can Light EV LIGHT Guangzhou Co., Ltd , http://www.evlightprofessional.com