Speaking of atmospheric haze, and then first of all to understand what is haze. Haze it is defined in the meteorology definition, it is defined as this: haze weather is defined as a large number of fine dry dust particles evenly floating in the air, so that the level of visibility less than ten kilometers of air generally muddy phenomenon, So that the distant light of the microstrip yellow, red, so that the black microstrip blue, it has become the atmosphere of the golden cloud. But in our environmental protection, the definition of haze is like this, it is said that the air of dust, sulphate, nitrate and other particulate matter composed of aerosol system caused by visual barriers we called haze. Often said fog and haze together, we say that is haze, but the fog and haze is different, the biggest difference is the moisture content, but the moisture content of more than 90%, we called fog, moisture content of less than 80% We called haze, between 80 and 90 is a mixture of haze. Fog and haze have some naked eye to see things, the fog color is milky white, green and white, haze color is yellow gray, fog boundaries are very clear, over the fog may be able to see the blue skies, haze and The surrounding environment border can not see, haze because of urbanization, industrialization, a major factor. When there is haze weather, the sky will show dark gray, visibility is not enough, haze and urban air pollution associated with the haze when the serious, people's production and health and health have a certain impact. We haze in Beijing haze level is divided into three levels, mild haze, moderate haze, heavy haze. Mild hail refers to less than 80% relative humidity, visibility greater than 5 km, less than 10 km, moderate haze air humidity less than 80%, visibility in the 2 km to 5 km view, heavy haze can see less than 2 km. These photos from Beijing in the second half of last year to the beginning of this year, the typical haze weather photos, we all empathy, from the second half of last year, good haze weather in the first half of this year is more frequent.
Speaking of haze, haze and PM2.5 often linked together, in fact, haze days PM2.5 often exceeded, PM2.5 refers to the atmospheric aerodynamics directly less than or equal to 2.5 micron particles, also known as Can be inhaled particles, his diameter does not make a human hair 20 points, respirable particulate matter into the human body system can enter the body after the blood involved in the body cycle, the health of the human body is very serious impact. PM2.5 in the air there are two main sources: First, a direct discharge of a source, he has a natural source, traffic dust, farmland dust, wind disturbance caused by emissions. The other is the human source, we are usually fixed source and mobile source. The source of the fixed source is produced by burning, producing the industrial production process. A mobile source refers to emissions from a motor vehicle. In addition, he is formed twice, by the discharge to the atmosphere which sulfur dioxide, nitrogen oxides and VOC in the air which meet certain conditions to produce a certain chemical reaction, the formation of nitrate, sulfuric acid and secondary organic solvent caused by the rise of 2.5. VOC Now a lot of research shows that VOC is a very important prerequisite for PM2.5, a lot of VOC sources will be introduced later. As the production and use of paint is the most important contributor to VOC. This photo just the Ministry of Environmental Protection, Dr. Zhu has been demonstrated to you, the definition of VOC in different countries and different areas of VOC definition is not exactly the same, Dr. Zhu also referred to our country in the development of our national VOC definition, on our national VOC Definition of the Paint Association Secretary-General Yang many times mentioned, because we do not have a clear definition of this country, different definitions contain VOC category is not the same, so this is now we face a very important issue, as if the Ministry of Environmental Protection has also been With the initial definition, including some VOC species have a guide, I believe that we will soon see some of the content.
On the classification and characteristics of volatile organic compounds to give you a brief introduction. Volatile organic compounds are collectively referred to as volatile compounds. There are thousands of species. Its characteristic molecular weight is very small, in the general conditions are relatively easy to gasification, the formation of organic matter in the process can also be generated in the chemical decomposition of organic matter or biodegradation process, the emission into the atmospheric environment. Volatile organic compounds and species are often determined by different methods. There are no special systems and special monitoring methods for the emissions and methods of measurement of volatile organic compounds, especially those of pollution sources, and now the Department of Environmental Protection is organizing experts in the preparation of these methods. VOC characteristics of a very strong activity, is a more lively character in the atmosphere, which in the atmosphere to a one-time volatile gaseous presence in the ultraviolet radiation under certain environmental conditions change to produce solid, liquid or secondary coexistence of particulate matter. With the drift of the weather drifting into the water and suddenly, polluting to our environment. VOC types are very many, VOC sources are also divided into human and natural sources, natural sources are relatively simple, we will usually discharge VOC plants, VOC emissions are relatively high activity. Volcanic eruptions will also discharge VOC. The anthropogenic sources mainly include fixed combustion sources, such as electric fields, and VOC emissions during boiler fuel combustion. There are emissions compared to refining, petrochemical this one, as well as industrial activities of the solvent use device activities, such as solvent use device with our furniture production, as well as mobile sources, mobile source is 2.5 the most important source, Beijing accounted for About 30%. There are oil storage and sales, as well as the source of life, the source of life is mainly from last year we began to speculation hot food fumes, dry cleaning industry dry cleaning process caused by emissions, as well as auto repair, Beijing Auto repair classified as a source of life. There are agricultural sources, the use of chemical fertilizers, pesticides caused by emissions.
We all know that the production of VOC coating toxicity, toxic VOC category accounted for about 30%, not only is relatively light on the skin, eyes, respiratory irritation or corrosive. Heavy on our nervous system, affecting our nervous system, liver, kidney, stomach these organs. The most serious is the carcinogenicity of the VOC atmosphere and other reactions that occur to form photochemical smog. VOC emissions of methane can increase the greenhouse effect, as well as VOC in the atmosphere and nitrogen oxides, sulfur dioxide, ammonium salts and the like to reflect the formation of secondary organic solvent, PM2.5 contribution is very large. VOC emissions to high altitude and ozone are reflected, the formation of ozone holes, can increase the radiation of ultraviolet radiation. VOC emissions in near-surface emissions are likely to form ozone, near-surface ozone on human health, in the high altitude can exacerbate the consumption of ozone, VOC emissions, whether in the ground or high altitude is a very bad thing. This is the VOC in the atmosphere which reflects the map, VOC to enhance atmospheric oxidation activity, strengthen the formation of PM2.5, in the process of reflecting the formation of ozone, but also and sulfur dioxide, nitrogen oxides reflect the formation of secondary organic solvent. According to our research and development in Beijing, the secondary organic solvent in the PM2.5 component accounted for about 20% of the proportion. VOC is now in Beijing is our PM2.5 and ozone these two air quality problems which play a very important role, and many types of VOC is toxic, directly harm the health of the human body.
"13th Five-Year Plan" period, China to complete the 2020 unit carbon emissions per unit than in 2005 decreased by 40% to 45% of the international commitment to low-carbon goals, and to complete the "Sino-US Joint Declaration on Climate Change" in China In 2030 or so to achieve the peak of carbon emissions in the long-term low-carbon development goals lay the foundation, while in the air pollution control and other environmental indicators have achieved remarkable results. To this end, the relevant state departments promulgated a series of environmental regulations, as mentioned above. According to China's "thirteen five" planning directory of environmental protection, resource planning related information, paint, paint additives, paint pigments industry should also be targeted to develop "thirteen" energy saving and environmental protection development plan. Mainly related to the following:
(1) to deepen the industry access mechanism research;
(2) energy saving and emission reduction;
(3) to promote the development of resource recycling technology, saving resources;
(4) improve the environmental incentive mechanism and punishment mechanism;
(5) improve the safety emergency system.
Paint and related industries in the development process of environmental issues are: VOC emissions, excessive waste emissions, heavy metal pollution.
In recent years, China's atmospheric environment by the foggy weather is increasing, causing the relevant state departments of great concern. The State Council General Office of the Ministry of Environmental Protection and other departments on the "promotion of air pollution prevention and control work to improve regional air quality guidance on the notice" (State Council issued 〔2010〕 33) as a symbol from the national level of formal pollution control work On the agenda; in September 2012 the State Council approved the implementation of the "key regional air pollution control" second five "plan", the VOC and sulfur dioxide, nitrogen oxides, industrial smoke dust together as the three districts and ten groups of prevention and control focus, The implementation of VOC pollution prevention and control work into the key prevention and control tasks; February 1, 2015 will be included in the scope of consumption tax levy, the construction of the VOC content of less than 420g / L (inclusive) of the paint exemption from consumption tax.
At present, China's total paint production, solvent-based paint accounted for about 49%, the rest of the water, powder, light curing and other environmentally friendly coatings. Compared with the developed countries, China's solvent-based paint ratio (US solvent-based paint accounted for about 30%, Japan is 35% to 40%, Germany is 20%), resulting in high VOC ratio, the majority of domestic paint lack of VOC limit Value standards, the standard has been compared with the developed countries more relaxed.
Since the reform and opening up 36 years (1978 - 2014), the proportion of environmentally friendly coatings increased by about 1.2% per year, "13th Five-Year" period, China's environment-friendly coatings accounted for 1% growth rate, by 2020 environmentally friendly Type paint accounted for from the current 51% for 57%.
For supporting products to upgrade the task and the old line transformation, do the following planning recommendations:
(1) out of a number of restrictions on a group to encourage a group. Phase-out of high-VOC low-solvent solvent-based automotive original paint, limited high-VOC low-solids car repair paint applications, to encourage water-based, high solids and other alternative environment-friendly coating applications New car line must be low VOC coating line The
(2) alteration. For the use of water-based paint has been reserved for the coating line, should be completed on the old line transformation, and according to the actual situation, do the end of governance, to achieve the purpose of VOC emission reduction and energy saving parallel; not reserved for water-based 3C2B coating Line, should be done step by step reconstruction planning, on the one hand can be converted into a high solid solvent-based 3C1B process, reduce construction costs, to achieve energy-saving emission reduction purposes; the other hand, as appropriate, the construction of more environmentally friendly water-based coating line.
(3) supporting product recommendations. Passenger car business, primer all the use of cathodic electrophoresis, in the coating and the basic paint all water-based; truck, box-type truck business primer all the use of cathodic electrophoretic paint, in the coating to achieve water-based or high solids, UV light curing And other environmentally friendly coatings.
(4) coating process improvement. Prohibit the use of paint utilization rate of less than 60% of the coating process to promote the robot automatically spray.
(5) VOC removal rate of more than 90% (inclusive) (non-key areas of more than 80%).
In 2014 the national ship coating supply is about 250 million L, about 325,000 tons, the annual VOC emissions of about 200,000 tons. In view of the particularity and functional requirements of ship painting, the most direct and effective means to reduce VOC emissions is to reduce the VOC content from the source.
(1) source control. The solids content increased from 72% to 80%, VOC decreased by 17.7%, construction equivalent film thickness, the amount of paint can be reduced by 11%, total VOC emissions by 26%; solvent-free products are basically free of VOC; Products compared to solvent-based products, VOC content can be reduced by more than 80% (Table 2-1). The control technology faces two problems: on the one hand, it takes time to develop new formulations, overcome technical barriers, and pass tests; on the other hand, the cost of paint is generally increased.
(2) improve the environment-friendly products supporting system. Some water-based marine coatings, high-solids solvent-based ship coatings, powder coatings and other related products have entered the application test phase, but the lack of supporting products restricts the development of product applications, therefore, product development at the same time, response to product development to pay more attention The
(3) water-based paint product technology breakthrough: to enhance the performance of water-based paint, such as water-based anti-corrosion primer used in water-based epoxy primer, water-based primer in the lack of reliability, consider the water-based coating and surface coating to do more technical research , Make up the undercoat performance.
(4) limit the production of high VOC low solids solvent-based marine coatings, VOC more than 500g / L or diluted VOC content of more than 600g / L paint should be restricted production or phasing out.
Steel coating is currently the main way to artificial spraying, large steel components to high pressure airless spray as the main construction methods, small components to air spraying as the main construction methods. Painting production line in the workshop or open-air construction methods are, no matter what kind of construction methods, the current VOC are unorganized emissions.
1, the development of low VOC steel structure anti-corrosion coating, reduce the volatile organic matter
(1) to promote a number of high solids coatings, such as high solids epoxy coatings, acrylic polyurethane coatings, aliphatic polyurea coatings, polysiloxane coatings have been launched with high solids products, and has been successfully applied at home and abroad.
(2) the application of a number of mature water-based paint, such as water-based acrylic paint, water-based epoxy paint, water-based polyurethane coatings, water-based inorganic zinc-rich paint. Although there are product application cases, but limited by the construction factors (winter low temperature construction) and the impact of product costs and not large-scale application, through product technology research and standardize the construction of the combination of ways to improve the product market share The
(3) to limit and eliminate a number of coatings. Solvent-based thermoplastic acrylic, perchlorethylene, chlorinated polyethylene, chlorosulfonated polyethylene and other coatings in the construction of more VOC, while the performance of these coatings can be completely replaced with other high-solid paint , Recommended to give restrictions or eliminated.
2, to improve the quality of coating corrosion to reduce the number of coating maintenance
The life cycle of steel products is often longer than the life of the coating, so throughout the steel product life cycle, the coating should be regularly maintenance and maintenance, and more than once the coating maintenance will produce a VOC release, so according to corrosion time requirements Targeted use of long-term anti-corrosion coatings, can effectively reduce the use of the entire steel structure of VOC emissions.
3, clean, standard construction
Promote the use of high-pressure airless spray, air-assisted airless spray, high pressure airless electrostatic spraying, thermal spraying and other high construction efficiency, low pollution coating technology, prohibit the use of high-pressure air spray in the open environment, reducing paint mist, VOC emissions; standardize the construction, improve the adhesion of grass-roots coatings to prevent the coating caused by the degradation of the coating layer, thereby reducing VOC emissions.
In the conditional workshop environment, it should urge to encourage the installation of back-end processing device, through the combustion, adsorption, absorption and other methods of the organic solvent generated during the recycling process after discharge and reduce pollution.
(1) break through water-based wood coating technology bottlenecks. Part of the product performance can not meet the requirements of solvent-based products, such as poor fullness, surface tension, single-component coating strength is low, poor sealing, surface repair difficult, absorbent tendons and other issues. Part of the shortcomings through the polymerization process improvement, molecular structure design, inorganic organic compound modification, nanotechnology and other means have been improved, but in the fullness, surface repair and other issues there are still large deficiencies.
(2) government procurement should give priority to the selection of water-based paint coated furniture. In the major government procurement projects, the proposed purchase of water-based wood coating paint furniture, to the people play a leading role.
(3) out of a number of restrictions on a group to encourage a group. Eliminate high-VOC solvent-based nitro wood coatings and other high-polluting products; limit other high-VOC solvent-based paint the new line of construction and production scale, and phase out; encourage water-based paint technology research and development and application.
(4) to urge and encourage the installation of wood furniture manufacturers to install waste gas process equipment and end processing equipment.
Develop low VOC environmentally friendly coatings, break through technical bottlenecks, reduce costs and improve quality. Water-based paint and high-solids solvent-based container coating full application still need time, need to constantly improve the supporting system, reduce costs, further reduce product VOC content, enhance corrosion resistance and coating strength, but also must solve the water-based paint winter repair problems , Making it more widely applicable.
(1) water-based paint in the container manufacturing industry has a certain application, such as water-based PVDC primer, water-based acrylic interior and exterior paint double supporting system, or water-based epoxy zinc-rich primer, water-based epoxy paint, Water-based acrylic paint three-layer supporting system, which can effectively reduce VOC emissions by 85%.
Development of bottlenecks The corrosion resistance of waterborne container coatings is still different from that of existing solvent-borne coatings, and there is a problem of winter repair due to temperature and humidity, which restricts its application. Lack of zinc-rich primer protection of the double protective system, anti-corrosion ability can not be compared with the three-tier system, although there are water-based epoxy zinc-rich primer research and development, and to achieve a three-layer water-based protection system, but the cost is too high, And anti-corrosion performance has also been questioned by the industry, so in the water-based anti-corrosion coatings and ancillary products and technology research there is still a long way to go.
Cost in 2012, subject to cost constraints, water-based paint system single-box cost of solvent-based paint 80 to 100 US dollars higher, if no major technological breakthroughs to reduce product costs, the cost will become the biggest obstacle to the promotion of water-based paint.
(2) high solids solvent-based coating. Has developed a high solid epoxy intermediate paint and high solids epoxy interior paint, high solids epoxy zinc-rich paint only to complete the test work, the system is not perfect.
(3) coating process upgrade. The use of workshop primer automatic roller coating, Zhengxiang drainage technology, in ensuring the quality of the premise, not only energy saving, and effectively reduce the amount of paint to achieve the purpose of VOC emission reduction.
(1) down the quality. Engineering machinery industry is highly competitive, down the quality of the benefits of the drive, the coating naturally requires inexpensive, but the water-based paint and high solids solvent-based paint materials and construction costs are high, therefore, the need for technical A breakthrough, reduce the environment-friendly coatings in the construction machinery industry on the application costs, to break its passive promotion model.
(2) to enhance surface adaptability. Engineering machinery steel plate is thick, the surface treatment without the ship, the automobile manufacturing request is high, therefore the surface treatment in the degreasing, phosphating, chemical residue, water film and so almost did not do the effective disposal, therefore need the paint has the high surface adaptability ( Such as low surface treatment coatings), which can reduce production costs.
(3) breakthrough product versatility. Engineering machinery parts more coating needs more types of paint, in ensuring the quality of the premise, the design of general-purpose anti-corrosion products, can effectively reduce the cost of painting and painting difficult.
(4) quick problem. Water-based paint is usually a slow drying rate, improve the drying rate of water-based paint can effectively open the water-based paint in the construction machinery coating to promote passive situation.
(5) the development of special coating repair. The original paint repair inconvenience, the development of low-VOC environmentally friendly repair special paint, fill the construction machinery repair market a huge gap.
(6) clean construction, efficient spraying. The use of robot spraying, electrostatic spraying advanced coating to improve paint utilization, reduce VOC emissions; reduce the amount of solvent used to recover cleaning solvent.
(7) to urge the installation of the end of the coating equipment, to do the collection of waste gas, discharge standards.
More than 80% of the domestic architectural coatings are water-based latex paint, VOC content is not high. However, the remaining 20% is still solvent-based architectural coatings, the VOC emission reduction task is still heavy. Therefore, the Ministry of Environmental Protection approved the national environmental protection project "architectural coatings VOC content limits and control of the way", China Paint Industry Association as a project collaboration unit to participate in this project, will focus on this part of the work.
(1) to carry out the domestic use of architectural coatings and the use of the type of industry research and market research, to master the different types of architectural coatings pollution characteristics;
(2) the establishment of VOC content detection and analysis methods, the domestic use of the main types of architectural coatings organization to implement VOC content analysis and analysis;
(3) screening for China's management level of VOC pollution prevention and control technology, the preparation of architectural coatings VOC pollution control technology guide;
(4) research abroad in the volatile organic products with the management of the policies, regulations and standards, put forward various types of building coatings volatile organic matter control system.
(5) Alternative targets for lead and heavy metal coatings. The current coating of lead and other heavy metals from the main source of the following four aspects:
① use lead and other heavy metal impurities in raw materials, such as aluminum, zinc powder, talc, kaolin, diatomaceous earth and other fillers with a certain amount of lead and other heavy metal impurities.
② the use of lead additives, such as the past, the use of lead carboxylate driers, vegetable oil alkyd resin alcohol catalyst Huang Dan and so on.
③ the use of lead and other heavy metal pigments and fillers, such as the previous use of red, yellow, alkaline lead silicate white, etc., is still using lead chrome yellow.
④ use of chromium surface passivation agent.
Among them, ① and ② in the technical and economic aspects is basically no problem, just to improve the coating limit and heavy metal related to the policy standards, strict supervision, can be fully consistent with lead and other heavy metal standards; ③ in the red Dan, Huang Dan completely To replace the technical and economic aspects of the problem, only need to strictly supervise; only lead chrome yellow alternative, both in technical and economic have some difficulty, "thirteen" period to replace lead chromium pigments to achieve the degree of industrialization promotion, The introduction of incentive policy mechanism for the replacement of lead paint project to complete the outstanding units, the state can give some incentives and subsidies to promote the progress of the work to eliminate lead paint; ④ in the metal coating surface treatment to replace the chromium treatment Agents in the technology has made great progress, the key in strict requirements and actively promote.
The film is wrinkled or cracked: the cause of the problem is the thick coating of water-based paint film at high temperatures, the film surface quickly dry film and thick inner layer is dry and slow, in the drying process of the flow of paint produced a poor tension , Resulting in the final film surface uneven, that is wrinkled; or directly lead to primer paint cracking phenomenon. So the construction, not a thick coating, should be taken thin coating, many times; while maintaining the furniture at temperatures above 15 degrees, humidity below 70%, well ventilated environment, so that the film is dry.
Poor adhesion between lacquers: the direct cause of poor adhesion between the paint interlayer is the construction, the substrate or coating between the no grinding, resulting in poor adhesion (because the water-based paint is a physical film, by the surface of the friction To improve the adhesion); indirect reason is the high temperature in summer, wet paint film and dry film interface to form a solid layer of the lack of time, so that the impact of adhesion. Therefore, the construction workers require construction, each layer to be fully polished, enhance the adhesion, while the construction arrangements in the morning and evening is appropriate to ensure that the inherent quality of the product can be reflected.
Paint white: the main construction environment is too much humidity, the coating process is too thick and other causes caused by the film. Because the summer temperature is high, some areas of air humidity. The dryness of the paint layer is accelerated with the increase of the temperature, but the working time is relatively slow. The painter may neglect the working time during the construction process, and immediately after the paint is dry, Resulting in the bottom of the paint layer is not fully dry, resulting in paint whitening phenomenon. So to master the construction of the intermittent time, a certain situation in the paint layer under the dry, and then the next process construction.
Lacquered sag: the main cause of the problem Paint more water, too thin, brush too thick, or too much air humidity, dry paint slowly, resulting in sagging. Therefore, the construction time to note that the amount of water diluted, thin coated many times, select the low humidity weather construction.
Stains: There are many reasons for the stains on the paint surface. For example: the moisture in the latex paint to dissolve the material on the walls and rust paint, with steel velvet rubbed the wall will produce rust, the wall of the dark tube leakage and other stains. To prevent stains, you can brush a layer of aluminum powder primer, if there have been stains, you can remove the stain at the latex paint, brush layer with aluminum powder primer, and then re-paint.
Loss of luster: the reason is not on the primer, or primer and the inner paint is dry on the direct light paint, the results of light paint is absorbed by the wood and lose luster. The poor quality of light paint is also a reason. With dry and wet sandpaper to wear the old paint, brush to polish the dust, with a clean damp cloth to wipe the surface, to be dry through, and then re-brush the top paint. It is important to note that in the low temperature environment painted, paint dry, it may lose luster.
Lacquered rough: the new painted surface rough, usually used in the paint is not clean or by the surrounding environment pollution. It is also possible that the paint is mixed with patent leather, which is dusted before it is precipitated and filtered, or when the paint is dry. To prevent this problem, clean paint and paint bucket must be used. Before using the old paint, must use paint filter paper or clean nylon stockings filter. In addition, the painted surface in the paint is dry when covered with a cover or cardboard to prevent dust. If the paint is rough, until it is dry, with wet and dry sandpaper polished smooth, wipe, and then re-brush on the paint. Pay special attention to the paint brush must be clean.
Paint dry: poor indoor ventilation or temperature is too low, the paint is dry slowly. It is possible to open all doors and windows to promote ventilation, or put a heater in the room to increase the room temperature. If it still fails to solve the problem, it may be painted on the surface greasy. This can be used to remove the paint by chemical paint removal or heating, thoroughly wipe the surface, and then re-paint.
Paint sticky insects: try to take advantage of the paint is dry when the bug ticked, and then stained with a little oil to repair the surface of light. If the paint has begun to dry, will have to wait for the film completely hardened, then the insects wipe, so do not make the surface confused mess.