1. Clean production in the printing industry is the only way to achieve sustainable development
China has 150,000 printing companies of all kinds, more than 3 million employees, and an annual output value of more than 100 billion yuan. It is the fastest-growing country in the world in recent years. In addition, China's printing companies exist: the total amount is surplus, the structure is unreasonable, and the layout lacks the characteristics of planning. Moreover, the traditional printing process has serious environmental pollution, which limits the further development of the printing industry. As new technologies continue to mature, the implementation of cleaner production is the only way to achieve sustainable development of the printing industry.
Cleaner production refers to the continuous application of environmental strategies for overall prevention in production processes, products and services with a view to increasing eco-efficiency and reducing risks to humans and the environment (United Nations Environment Programme 1996). Clean production is a comprehensive measure that aims to save energy, reduce consumption and reduce pollution, and uses management and technology as means to achieve pollution control throughout the entire industrial production process and minimize the generation of pollutants. Relevant printing companies implement cleaner production, including clean raw materials, clean production processes and clean products. First, choose non-toxic, harmless, renewable, and degradable materials, especially paper, ink, and plate materials that consume a large amount; second, require no pollution or reduce pollution in the printing process, such as the use of advanced Printing technology and equipment, less or no chemical agents harmful to the environment in the printing process, etc .; third, require printed products not to cause harm to consumers and the environment.
2. Pollution sources in the printing industry
The traditional printing industry has basically eliminated the lead printing process after the transition from "lead and fire" to "light and electricity", and the degree of pollution of the printing environment has also been greatly reduced. However, there are still quite a few pollution sources in printing enterprises, mainly including air pollution, water pollution, noise pollution and so on. Air pollution is mainly the volatilization and dust of various raw materials and auxiliary materials, such as ink in the printing process, adhesives and paper dust in the binding process, etc .; water pollution is mainly the waste water such as the designated film, developer and cleaning agent Pollution; noise pollution, mainly the noise of printing equipment, generally above 80 decibels.
1. Fountain solution
The fountain solution is a necessary condition to ensure that the blank part of the printing plate forms a hydrophilic salt layer. The alcohol dampening system currently used in offset presses, isopropyl alcohol is one of the additives of dampening solution. Compared with the traditional water dampening system, this dampening method greatly reduces the amount of water, and avoids paper deformation and excessive emulsification of ink caused by excessive water, thereby greatly improving the printing effect. However, the alcohol vapor produced by isopropanol volatilization is toxic and has a bad smell, which will have a harmful effect on human health; moreover, isopropanol is also a photochemical oxidant, which is the same as other trace gases present near the ground , Exposure to sunlight will form ozone and cause the so-called "summer smog" phenomenon. Photochemical smog can irritate people's eyes and respiratory system and endanger people's health and plant growth. Therefore, isopropyl alcohol is a chemical that is harmful to the environment and the human body. It is an inevitable trend to reduce its use in printing .
2. Plate film and waste fixer
At present, offset printing is the most used in printing, and most of the plates used in offset printing are still printed on the machine by making a Ps version from the film produced by Ij2008.2. The film is a silver salt photosensitive material, which contains silver ions, and the waste fixing solution after fixing contains a large amount of silver ions. If these substances directly enter the environment, heavy metal silver ions can pollute natural water bodies and cause harm to the environment. At the same time, The base of the film is a polymer compound that degrades in the environment and pollutes the soil.
3. Ink
The main cause of atmospheric environmental pollution is solvent-based ink, which is composed of pigments, binders, solvents, fillers and auxiliary agents. The solvents used are mainly organic solvents such as aromatic hydrocarbons, esters, ketones and ethers. Most of these solvents are toxic and will contaminate the packaged foods, medicines and cosmetics; they are volatile and have a strong pungent odor, which will pollute the environment and affect the health of workers; in addition, organic solvents are flammable and explosive , There are hidden dangers in production safety.
4. Plastic film
In the book binding, the plastic film is favored by publishers and consumers because of its folding resistance, abrasion resistance, protection of printed matter to increase gloss and low cost. However, the printed paper after the film becomes a paper-plastic product, which is inconvenient to recycle and recycle, and cannot be naturally degraded to cause environmental pollution. In addition, the use of toxic volatile solutions such as toluene cyanide water in the coating process can harm workers' health and pollute the environment.
5. Oily glazing materials
The glazing process is a process for finishing the surface of the printed matter. After glazing, the gloss, smoothness and stiffness of the surface of the printed matter can be increased, which can protect the printed matter and increase the appearance. However, the thinner used for oily glazing materials is mainly toluene, and toluene is a toxic and volatile substance. The human body inhaling a certain amount of toluene will cause respiratory system and blood system lesions. Therefore, the oily glazing process does not comply with green environmental protection. Requirements, especially the packaging of medicines, food and other commodities and children's toys, children's books should not use oily glazing technology.
6. Plastic printing waste
With the rapid development of the printing and packaging industry, printing of organic polymer materials such as plastics is becoming more and more common. The plastic printing waste produced by printing plants is a kind of solid waste that cannot be ignored. Due to their water insolubility and extremely difficult in nature Degradation, if directly into the environment will inevitably cause harm. If incinerated, it will produce a large amount of strong carcinogens such as dioxins with strong toxicity. Therefore, plastic printing waste must be properly processed.
7. Effects of noise pollution and temperature and humidity
Printing machines and various transmission mechanisms, air compressors and air pumps, drying equipment and various other supporting machinery will generate noise. The noise generated by the cooling tower of the equipment of the binding production line is also very large. The failure rate of electronic components increases with increasing temperature. The increase in temperature from the circuit will deteriorate the circuit performance and cause equipment instability. Electronic equipment has strict thermal design during design and manufacture, and can operate stably for a long time under normal ambient temperature. The impact is from high temperature and high humidity conditions and the workshop environment. [next]
3. The methods and measures of cleaner production in the printing industry
1. CTP technology
CTP technology is a fully automated integrated production system that integrates precision equipment, photoelectric technology, digital imaging technology, computer software technology, and new plate technology. CTP is very beneficial to environmental protection. Regardless of whether there is water or waterless printing, when CTP is adopted, it does not require development processing during the plate-making process, which can be said to be efficient, high-quality and pollution-free. The use of digital photography technology to produce complete digital data does not require the development process of pictures, which is beneficial to the protection of the environment.
2. Waterless offset printing, alcohol-free printing process
Waterless offset printing is an offset printing process without fountain solution. Since there is no fountain solution, there is no series of pollution problems such as volatilization of organic compounds. Alcohol-free printing is to replace the isopropyl alcohol in the alcohol fountain solution with a mixture of ethers, ethylene glycol and other additives. This alcohol substitute has low volatility, high ignition point and no irritation. It is an environmentally friendly printing fountain solution.
3. Inkjet printing
Inkjet printing relies on a computer to control multiple nozzles to eject charged and uncharged ink droplets according to the intelligence instructions in the graphic section. The former is captured in a designated recovery tank, and the latter falls onto the paper for imaging. It is characterized by no printing plate, no pressure, reduced energy consumption of the printing press, no noise, and improved printing working environment. In addition, because it is non-contact printing, it can be used for large-area prints. At the same time, in terms of printing carrier, the range of paper used for printing has become wider, and color patterns can also be printed on textiles. In terms of application, inkjet printers have entered the printing industry with the fifth printing method and are showing their talents. They have been used for the popularization of DDCP for offset printing at the forefront of CTP. Facts prove that it is a green and environmentally friendly process.
4. Waterborne glazing process
Both plastic coating and oil-based glazing will cause greater harm to the environment, and the thinner used in water-based glazing is non-toxic, odorless, and pollution-free water. From the perspective of environmental protection and human health, water-based glazing The process is undoubtedly advantageous.
5. Flexo printing
The flexographic plate is a relief printing plate of a photosensitive rubber plate. In addition to its own advantages and technological progress, flexographic printing is one of the most important factors is that it meets the requirements of environmental protection and green packaging, can be widely used non-toxic, no residual solvent, no environmental pollution ink and UV ink.
6. Use water, ink, UV ink
Water-based inks are recognized as environmentally friendly printing materials. Since water is a polar substance, the water-based ink does not contain or contains a very small amount of organic solvents according to the characteristics of the compatibility of polar substances and polar substances. Therefore, water-based inks The biggest feature is the reduction of UOC emissions, thereby avoiding atmospheric environmental pollution, improving the atmospheric environment of the printing work in the workshop, which is beneficial to the health of workers. It can completely eliminate the harm of certain toxic and harmful substances in the solvent ink to human body and the pollution to the packaging products, and is especially suitable for the items with high hygienic conditions such as food, beverages and medicines in the packaging products. In addition, it can not only reduce the fire hazard caused by static electricity and flammable solvents, but also reduce the residual solvent odor on the surface of printed products.
7. Use advanced scientific methods to timely monitor the atmospheric environment
Take corresponding measures and means to make the printing car company in an optimal temperature, humidity and good ventilation environment, so as to provide a good external environment guarantee for the production process. The moisture content of paper and cardboard when they leave the factory often does not meet the printing requirements (should be 6% -7%), coupled with imperfect packaging, after a long period of transportation or stored in a paper warehouse lacking good conditions for a long time, such When printing paper, there will be serious failures such as poor paper feed, uneven paper collection, wrinkles, inaccurate overprinting, and dirty back, etc., resulting in a large number of waste products. Therefore, we installed air conditioning equipment in the offset printing workshop to keep the temperature and humidity of the workshop within a certain range, and adjusted the humidity of the paper and cardboard sent to print to balance its moisture content with the relative humidity of the workshop. We mainly use the natural hanging method, that is, one week before starting printing, the paper to be printed is cut and placed in the printing workshop, so that it is stored in the printing workshop and under similar conditions of temperature and humidity at startup, so that it is the same as the workshop Temperature and humidity balance. Do not put paper or cardboard on the concrete floor. We lay it flat on a wooden paper table. The above measures have achieved very good results. In addition, the humidity adjustment method of the paper drying machine can be used, the temperature of the paper can be raised and lowered to achieve uniform moisture content of the paper stack, and infrared radiation can be used to eliminate the phenomenon of the lotus leaf edge of the paper stack. Because the humidity of the workshop has a certain tolerance, it is possible to choose a dry and wet bulb thermometer with a simple structure, a low price, and different measurement accuracy to monitor the temperature and humidity of the workshop. According to the readings of the wet and dry bulbs, the relative humidity can be found. If you need to know the daily humidity changes, you can use a self-recording hygrometer to record 24 hours. According to the law of daily change in order to carry out humidification and dehumidification treatment in time. The impact of meteorological conditions on printing varies from place to place, and the scale of college printing plants is not large. New factors may appear at any time. Special influencing factors require special attention and research.
China's printing industry has been developing extensively for a long time under high consumption and high pollution. However, with the deteriorating environmental quality and the shortage of resources, we must change the traditional development model, use the first deletion technology, promote cleaner production, and vigorously develop green planing printing is the most ideal choice. Only in this way can our printing industry change from big to strong and achieve sustainable development.
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