Environmental pollution and its treatment in the h

2022-08-08
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Prevention of pollution, environmental governance and adherence to the strategy of sustainable development are the internal requirements for enterprises to integrate into the world economic trend and establish a modern enterprise system after China's entry into WTO. In recent years, the requirements for environmental protection of printing and packaging at home and abroad are getting higher and higher. Facing the reality, how should the printing industry deal with it? The principle of preventing pollution and environmental protection is to correctly use all kinds of chemicals, not only to reduce waste at the source, but also to promote the reduction of the impact of various chemicals on the environment in the production process

in printing enterprises, manuscript, film, printing plate, ink, fountain solution, polishing solution and printing machine washing solution constitute an integral part of the printing process and are important factors in printing. Some of them form part of the finished printing products, and some of them become solid, liquid and gaseous wastes after the completion of their functions, which are left in the printing workshop or enter the environment. We analyze this in order to effectively control the environmental pollution caused by various factors. The cutting is completed by just changing the auxiliary tools. First of all, we should find ways to use safe products to reduce or avoid environmental pollution. At the same time, we should also find a reasonable use method of chemicals that have to be used at present to control their dosage to reduce environmental pollution

first, the main source of pollution in the printing process is ink. At present, traditional solvent based inks are widely used in the printing industry. Solvent based inks are composed of pigments, binders, solvents, fillers and auxiliary agents. The solvents used are mainly aromatic hydrocarbons, esters, ketones, ethers and other organic solvents. Most of these solvents are toxic and will pollute the packaged food, drugs, cosmetics and other items; It is volatile and has a strong pungent smell, which will pollute the environment and affect the health of workers; Organic solvents are flammable and explosive, and there are hidden dangers in production safety

the second is fountain solution. Fountain solution is a necessary condition to ensure the formation of hydrophilic salt layer in the blank part of the printing plate. At present, alcohol fountain system is widely used in offset printing machines, and isopropanol is one of the additives of fountain solution. Compared with the traditional water moistening system, this moistening method can greatly reduce the amount of water, and avoid the paper deformation and excessive emulsification of ink caused by excessive water, so as to greatly improve the printing effect. However, due to the toxic alcohol vapor produced by the volatilization of isopropanol, which has a bad smell and will have a harmful impact on human health, many developed countries stipulate that the threshold limit value of isopropanol in the workplace is only 200~400 ml per cubic meter; Moreover, isopropanol emissions will also pollute the environment. Isopropanol is a photochemical oxidant. Like other trace gases near the ground, it will form ozone when exposed to sunlight, resulting in the so-called "summer smoke" phenomenon. Photochemical smoke will stimulate people's eyes and respiratory system, endanger people's health and plant growth. Therefore, isopropanol is a chemical harmful to the environment and human body, It is an inevitable trend to reduce its consumption in printing

third, film and waste fixing solution. At present, offset printing is the most used in printing, and most of the plates used in offset printing are made into PS plates by Phototypesetter. Film is a silver salt photosensitive material, which contains silver ions, and the waste fixing solution after fixing also contains a large number of silver ions. If these substances enter the environment directly, the heavy metal silver ions can pollute the natural water body and cause harm to the environment. At the same time, the film base is a high molecular compound, which is extremely difficult to degrade in the environment and pollute the soil

fourth, plastic coating. Plastic film mulching is favored by publishers and consumers because of its folding resistance, wear resistance, protection of printed matter, increased gloss and low cost. However, plastic film mulching cannot be degraded and becomes white pollution, and the paper after film mulching cannot be recycled, resulting in a waste of resources. At the same time, toxic volatile solvents such as toluene and Tianna water are used in the film mulching process, which will endanger the health of workers and pollute the environment

fifth, oily glazing materials. Glazing process is a process of finishing and processing the surface of printed matter. After glazing, the gloss, smoothness and stiffness of the surface of printed matter can be increased, which plays a role in protecting printed matter and increasing beauty. However, the diluent used in oily glazing materials is mainly toluene, which is a toxic volatile substance. Inhalation of a certain amount of toluene by human body will lead to pathological changes in the respiratory system and blood system. Therefore, the oily glazing process does not meet the requirements of environmental protection, especially the packaging of drugs, food and other commodities, children's toys, children's books and so on

sixth, plastic printing waste. With the rapid development of the printing and packaging industry, the printing of organic polymer materials such as plastics is becoming more and more common. The plastic printing waste produced by printing plants is a solid pollutant that can not be ignored. Because of their water insolubility and extremely difficult to degrade in nature, it will inevitably cause harm if it directly enters the environment. If the waste is burned nearby, a large number of highly toxic gases such as dioxin will be produced. At very low concentrations, dioxin can distort people and animals, and it is a strong carcinogen, which will seriously pollute the surrounding air. Therefore, plastic printing waste must be treated reasonably

Second, the basic countermeasures for developing green printing

first, vigorously develop and develop water-based inks, UV inks and other new inks that meet the requirements of environmental protection. Water based ink is recognized as an environmentally friendly printing material in the world. Because water is a polar substance, according to the solubility of polar substances and polar substances, water-based ink does not contain or contains a very small amount of organic solvents. Therefore, the biggest feature of water-based ink is to reduce the emission of VOC (volatile substances), so as to avoid air pollution, improve the printing environment, and be conducive to the health of workers. It can completely eliminate the harm of some toxic and harmful substances in solvent ink to human body and the pollution of packaging products. It is especially suitable for packaging and printing products with strict sanitary conditions, such as food, beverage, medicine and so on. In addition, it can not only reduce the fire hazards caused by static electricity and flammable solvents, but also reduce the residual solvent odor on the surface of printed matter

second, develop and promote flexographic printing. In addition to its own advantages and technological progress, one of the most important factors of flexographic printing is that it meets the requirements of environmental protection and green packaging. It can widely use non-toxic, solvent-free and environmental pollution-free water-based inks and UV inks

third, develop and improve the waterless offset printing and alcohol free printing process. Waterless offset printing is an offset printing process without fountain solution. Because there is no fountain solution, there is no series of environmental problems such as the volatilization of organic compounds. Alcohol free printing is to replace isopropanol in alcohol fountain solution with a mixture of ether, glycol and other additives. This alcohol substitute has low volatility, high ignition point and no irritation. It is beneficial to workers' health and production safety. It is an environmental friendly printing fountain solution. For example, an alcohol substitute called substitutixhd has been developed abroad. Extensive tests have confirmed that it is a substance that has no bad smell, does not harm health, and will not pollute the environment. At the same time, the time when ink emulsification begins to occur is slower than using isopropanol, no ink will penetrate the fountain system, and the printing speed is no less than alcohol printing. It is an economic and environmentally safe product

fourth, develop direct plate making technology without film (dry film imaging). Dry film imaging does not need to go through the exposure and development process of traditional film, nor does it need a developer. Naturally, it does not need relevant equipment and operation process. In particular, it can be imaged without using any chemical agents, which is extremely beneficial to environmental protection and is called "green" imaging technology

fifth, develop water-based glazing technology. Plastic coating and oily glazing will cause great harm to the environment, while the diluent used in water-based glazing is non-toxic, tasteless and pollution-free water. From the perspective of environmental protection and human health, water-based glazing process undoubtedly has advantages

sixth, use environmental protection technology to treat waste gas and waste. All kinds of wastes generated in the printing process are collected specially, and valuable articles such as paper are recycled. Materials that are difficult to degrade and harm the environment, such as film and plastic film, are recycled by the garbage recycling station for resource treatment or sanitary landfill. At this stage, due to process and other reasons, we have to use all kinds of polluting printing materials, such as oily ink, oily film coating, oily glazing, etc. the harmful and toxic gases produced in the process of their use can be treated by means of suction adsorption, absorption, catalytic combustion and other methods, so as to reduce the concentration of harmful gases in the working environment, reduce the harm to workers, and reduce the pollution of harmful gases to the environment

with the improvement of environmental protection requirements and the strengthening of people's awareness of environmental protection, vigorously developing and developing environmental friendly printing materials, improving printing technology, developing and promoting environmental friendly printing technology has become an important topic for Industry Research in the 21st century. At present, there is still a big gap between China's printing industry and developed countries in terms of environmental protection technology. Therefore, we should increase investment in the research and development of environmental protection products and processes for connector printing used in EV, and do a good job in promoting science and technology. The author believes that as long as we continue to study and practice, green printing will be popularized in China in the near future, and green printing products will go hand in hand with our lives

the company also continues to dig deep into customers in subdivided industries

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