How to improve the efficiency of water-powered car paint construction?

With the increasingly strict national environmental regulations promulgated and implemented, coating requirements are getting higher and higher. Coating not only ensures good corrosion resistance, high decorative performance and high construction performance, but also uses good materials and processes to reduce the emission of volatile organic compounds (VOCs). Water-based paint because of its environmental protection components, gradually become the main force of

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water-powered paint can not only effectively improve the efficiency of maintenance, but also has a strong covering capacity, can reduce the number of spray coatings and the amount of paint used, to reduce spray time and spray costs. And water-resistant paint does not contain benzene, non-toxic and non-irritating odor, harmless to human body, and has water-resistant, wear-resistant, anti-aging characteristics. For automotive applications, the broad role of water-based paint is reflected in the most vivid, bringing about a major change in the situation.
1. The difference between water-like paint and oily paint
1, thinner is different: the difference between water paint and paint is that the "thinner" used in water paint is water, according to the need for different proportions of water from 0 to 100%. The "thinner" used in paints is an organic solvent, and the proportion of paints adding organic solvents is about 80% to 120%.
2, different environmental performance: water paint with water as a thinner, no benzene, toluene, xylene, formaldehyde, free TDI toxic heavy metals and other harmful carcinogens, non-toxic non-irritating odor, no impact on human health safety. The thinners often used in paints are chemicals such as banana water and xylene, which contain large amounts of harmful carcinogens such as benzene. And there is an extremely strong irritating odor, generally after 1-2 months of use, the odor can be dispersed.
3, the function is different: water paint not only does not pollute the environment, but also the paint film is full, the effect on the surface of the object is crystal clear, flexible is excellent and has water resistance, wear resistance, aging resistance, yellowing resistance.
4, the cleaning cost is lower: spray guns using solvent-based paint must be cleaned with organic solvents, and used cleaning agents can no longer be recycled. The spray gun using water-like paint only needs general water to complete the whole cleaning process, and 90% of the cleaning water can also be recycled, not only to save the purchase cost of cleaning agents, but also effectively reduce VOC emissions.
5, in line with national environmental requirements: water-colored paint VOC content in line with the relevant laws and regulations of various countries, to avoid enterprises or individuals may face legal disputes.
2. Technical features of water-based paint spraying
The evaporation of water in water-based paint is mainly controlled by adjusting the temperature and humidity of the paint chamber, while solvent-based paint can adjust the evaporation rate of the thinner to adjust the applied solids. Water-based paint is usually applied solids 20% to 30%, and solvent-based paint is applied solids up to 60% to 70%, so the smoothness of water-based paint is better, but at the same time need to heat the flash dry, otherwise easy to appear hanging, bubbles and other quality problems, so the control technology of paint fluidity is the key to the design of water-based paint.
 1． Technical characteristics of equipment
(1) paint room and drying room
First, because the corrosion of water is greater than solvent, so the paint room's circulating water treatment system needs to be made of stainless steel, and secondly, the air flow of the spray chamber is in good condition, wind speed control at 0.1 Between 2 to 0.6m/s, or air flow reaches 28000m3/h (normal paint room can meet this condition), the same drying room due to the high moisture content in the air will also cause corrosion of the equipment, so drying indoor walls also need to use anti-corrosion materials manufacturing.
(2) automatic spraying system
water-based paint spraying room the best temperature of 20 degrees C to 26 degrees C, the best relative humidity of 60% to 75%. The allowed temperature is 20 to 32 degrees C and the allowed relative humidity is 50% to 80%. Therefore, the paint room must have a suitable temperature control and humidification device. Domestic car paint room in winter can be temperature and humidity, but in summer there are few temperature control wet, because the need for cooling capacity is too large, so there are few cold air. Therefore, in high temperature and high humidity areas, if the use of water-resistant paint, must be installed paint room central air conditioning, summer also need to send cold air, in order to ensure the quality of water-resistant paint construction.
(3) other equipment
water-based paint spray gun: In general, water-based paint spraying will choose a gun with high flow low pressure technology (HVLP). One of the characteristics of HVLP is the high air volume, usually 430 L/min, so it can improve the drying speed of water-based paint. Although the HVLP spray gun air flow is large, but the atomization is low (15 m), in a dry climate, but because the drying speed is too fast and make the water paint level is not good, then only the use of a high atomization (1 μpm) medium pressure medium flow spray gun will have a better overall effect. In fact, for car owners, the drying speed of water-like paint does not make any sense, they see the flatness, gloss and color of the paint. Therefore, when spraying water-like paint must not be quick, but more attention should be paid to the overall performance of water-like paint, so that the owner is satisfied.
water-based paint blower: Some sprayers feel slower to dry than solvent-based paint in practice, especially in summer. This is because solvent-based paints evaporate faster and dry easily in summer, while water-based paints are less sensitive to temperature. From the average flash drying time (5 to 8 min) of water-based paint alone, it is actually less than solvent-based paint. Of course, to do this, a hair dryer is essential. The hair dryer is a tool for artificial drying of water-based paint after it has been sprayed. At present, most of the mainstream water-powered paint hair dryer guns in the market have achieved the effect of increasing air flow through the Venturi effect.
compressed air filtration equipment: unfiltered compressed air contains oil, water, dust and other pollutants, they are very harmful to water-based paint spraying operations, will cause a variety of paint film quality defects, but also may cause compressed air pressure and air fluctuations. Rework due to compressed air quality problems not only increases labor and material costs, but also hinders the smooth running of other work. In order to obtain high-quality compressed air, high-precision filtration equipment must be used. For example, DVFR-8 oil-water separators produced by DEVILBISS come with a total of 3 filter bottles. Section 1 filter bottle built-in spiral centrifugal oil and water separation device, can effectively separate oil and moisture, brass mesh filter can filter more than 5 m particles, and filter element can be cleaned. Section 2 filter bottle fine fiber filter, can filter more than 0.01 m particles, can remove floating matter. The activated carbon filter in the section 3 filter bottle filters the oil vapor in the compressor and removes organic odors, filtering particles above 0.003 pm.2． Spraying of water-based paint and spraying of water-based paint
(1) water-based paint
using a gravity spray gun (SART HVLP1.3 or RP1.3mm) using two spray methods (dry and wet spray).
(2) water-based paint flash drying
Because water-based paint and matte varnish are "wet and wet" construction, so water-based paint has pre-drying problems, that is, the vast majority of the paint coating of water, solvent-assisted evaporation. Experiments show that the solvent content (mainly water) of water-based paint coating should be reduced to less than 10%, and the sprayed hood varnish should not dissolve the paint layer and produce blisters, affecting the appearance quality. If the usual temperature conditions flash dry, water-based paint solvent content can not reach less than 10%. Therefore, proper forced drying must be carried out before the hood varnish is sprayed on the water-color paint. A common forced drying device is a hair dryer, which should be blown out in the same direction as the air flow in the paint room. The hair dryer must not be perpendicular to the paint, as this will cause paint defects. The varnish coating can be sprayed after the paint layer has been fully dried. First, mix varnish (e.g. P190-68505P190-6060 according to varnish: curing agent: diluent 2:1:5% to 10% ratio provisioning). Medium concentration of varnish sprayed two layers, drying time is about 5 to 7 min per layer. A high concentration of varnish sprayed one and a half layers (fog cover spray one layer, wet spray one layer). The drying time is about 10 to 15 min.Three, water-based paint construction matters
(1), because water-based paint organic solvent is very few, there is no reaction with the bottom (popularly speaking, biting paint)

(2), water-like paint ratio is 10%: 100 grams of water-like paint only add 10 grams of water-like thinner, water-like paint cover strong!
(3), before painting with oily de-oiling agent de-oiling, and then water-using de-oiling agent and then wipe! This step is very important, do not try to save trouble, because can greatly reduce the risk of problems, water-de-oil remover must also wipe!
(4), filter water-based paint to use a special funnel, in addition to water-based paint dedicated dust cloth, usually also used, but to wipe lightly, it is easy to scratch!
-based paint for the color easier to adjust out, solvent-based paint easy to color, water-based paint is different. Water-like paint for doing the bottom requirements are quite strict, once the problem, it is difficult to deal with, spray can no longer touch water. Compared with traditional oily automotive paint, automotive water-based paint can greatly reduce the emissions of organic solvents in the application, can reduce the amount of paint up to 2/3, but also in the vehicle coating production process to reduce the average heat consumption per car more than 40%, greatly reducing the energy consumption required in the automotive production process. Moreover, water-resistant car paint also has the advantages of good paint leveling, bright paint color, no ripples, strong paint hardness, excellent scratch resistance and excellent weather resistance. Therefore, now Europe, the United States, Japan's mainstream auto companies are mostly using water-based car paint system. In the future, automotive water-based paint is also the main direction of automotive paint development.