Quality control and cost control of waterborne coatings in the steel drum industry Wen/Wang Gaofeng Xi'an Xinyida Petrochemical Co., Ltd. Wang Gaofeng There are many factors in the use of water-based paints that increase the cost of use, reduce the quality or cause large quality accidents, so there must be a systematic solution to obtain safe and quality production. First, the substrate processing (pre-treatment of the sheet to the sprayed image) 1. Degreasing and phosphating The untreated surface of the oil on the surface of the sheet and the rusted and ash particles on the treated substrate will affect the quality of subsequent spraying. 1 The oil is not cleaned and oily (because the oil shrinkage is the oil spot that is removed by the oil, the phosphating is not on, causing oil shrinkage.) 2 The oil is not treated cleanly, not obvious, and the keyhole cannot be formed. The color of the treated workpiece is different, which affects the adhesion and water resistance. 2, after the substrate treatment with rust, with ash particles (alkaline) These two kinds of particles are highly invasive particles. Because of the shortcomings of water-based baking varnish being swollen in water after film formation, the paint film will invade water for a long time, while rust spots and alkaline particles will absorb water and invade water. Destroy the paint film. 3, plate oil Our company's coatings are inherently oil-repellent and do not have any effect on the appearance of the coating. Not cleaned, too much oil can increase the oil-resistant additives to improve, but the increase in coating cost has limited improvement in coating depth quality, but the appearance is improved. 4. Some plates have oil in the gap during processing. After oil removal and phosphating, they ooze again, which affects the quality of the coating. When the oil quantity is small, the adhesion is reduced. When the oil quantity is large, there are shrinkage holes. The quality has a great impact and is not well resolved in the later period. 5, drying after degreasing and phosphating 1 To dry the water, before the steel drum runs to the spraying line, the temperature is too high, the flow level is poor, the coating will be thickened, and the adhesion will be reduced. 2 The solution should be cooled by multiple times, the drying temperature is lowered, and the steel barrel is cooled to below 100 degrees when it is baked. Because water-based paints are diluted with water, water will instantly vaporize and not level out at temperatures above 100 degrees, so doing this work can reduce costs and improve quality, but it is also difficult. Second, the spraying line: 1, viscosity The water-based paint is sprayed at 25 seconds to 45 seconds (25 °C). The viscosity of the coating is determined by the speed, workpiece temperature and coating thickness. The number of seconds of spraying directly affects the cost of use. (Thickness 25μm±5μm) The coating is too thick. Or too thin has an impact on quality. 2, pressure According to the number of nozzles, distance, viscosity, room temperature, fine adjustment. 3, flow and speed Infinitely variable speed: 60 rpm ± 10 rpm (speed, viscosity, pressure) changes affect flow (increasing or reducing costs). 4, water vapor backflow In the process of spraying, a large amount of water vapor is generated during the spraying process. When the exhaust of the spray booth is discharged to the outside, a large amount of water vapor is condensed through the exhaust pipe and then flows back to the induced draft fan. Therefore, it is recommended that you make a diversion tank next to the induced draft fan to introduce the condensed water into the circulating pool of the air curtain. The flocculant separates the water from the aqueous coating so that the recycled water can be reused. Third, the baking line As early as ten years ago, our company was equipped with Beijing aviation air equipment regardless of electricity, coal, gas, oil, etc. In 2000, Baoji Co., Ltd. proposed that the front end of the baking line is low, the rear end is high, and the level is good. Save energy, reduce investment costs and product costs, and quickly promote it in the industry. Because each baking equipment is different, the chain running speed is fast and the baking temperature is high, and the slow temperature is low. If the chain speed is not increased, the coating will not dry and form an effective protective layer, which will result in poor water resistance, poor UV resistance, mechanical damage during transportation, and incalculable loss. There are still many barrel factories that are still aiming to reduce costs and are on the verge of causing major quality accidents. ã€Relevant information】 Problems in the application of water-based paint in chemical barrels First, the main reasons for the flow adjustment: 1. The temperature of the barrel of the spraying station is too high; the recommended temperature should not exceed 50 °C; 2, the thickness of the spray paint film does not meet the requirements; 3. The leveling time is too short after spraying. Second, the main reason for sag 1. The barrel has no temperature or the temperature is too low; 2, the pressure is too large; 3, the barrel speed is low; 4. Nozzle atomization is not good; 5. The viscosity of the water-based paint is too low; Third, the main reason for low gloss 1. The paint film is too thin; 2. The baking temperature is too high; 3. Flow adjustment; Fourth, the main reason for flash rust 1. The dry film thickness is too low; 2, leakage spray; 3. Poor water resistance; 4, the substrate processing is not thorough; Fifth, the main reason for shrinkage 1. The coated object itself is not cleaned; 2. The barrel body water is not dried; 3. Compressed air contains oil and water; 4. The oil-based paint exchange water-based paint pipe is not cleaned; 5, the paint itself problem; Special steel drum painting problem First, some problems in the application process of two-color barrel 1. The spray layout is unreasonable; 2. The pressure and nozzle do not match; 3. The nozzle model is not suitable; 4, the barrel temperature is low; 5, the viscosity is too low; Second, the internal coating (honey barrel and juice barrel inner wall coating) application of sagging and leakage problems: 1. The nozzle is not suitable for use; 2. The position of the gun body and the angle of spraying are not suitable; 3. The barrel temperature is low; 4. The viscosity of the coating is not suitable; Paint drop phenomenon during storage and transportation When the water-based steel drum coating is placed in the cold storage, water droplets will be generated in the cold storage, and the paint film will fall off during the long-term intrusion. Many end-users, after the steel drum is packaged, must be transported by car, transported by ship, and friction will be generated during the transportation of the car. When the ship is transported, it will encounter corrosion caused by the marine climate and produce paint. Combine the above questions, sum up the points to control 1. Pretreatment of the substrate 2, the thickness of the paint film 3, baking temperature and time 4, leveling (leakage) ã€Company Profile】 The water-based chemical barrel coatings and juice barrels produced by our company have been used in large quantities for 6 years. They have solved the problem of falling paint during automobile transportation and ship transportation, and have better resistance to UV and chemical resistance than oil-based coatings. Our company was established in 1998 and covers an area of ​​about 20,000 square meters. It is a professional water-based paint production enterprise integrating research, production and sales. Our company mainly researches the inner and outer wall coatings of steel drums, amino baking varnish, and is in process. The barrel industry has been well received by everyone. The main customers of the company's products are CNPC, Sinopec and domestic and foreign well-known juice packaging steel drums supporting enterprises. Since 2010, our company has decided to upgrade the products to develop water-based paints for monochrome and two-color barrels, water-based chemical barrel inner wall coatings, water-based honey barrel inner wall coatings and water-based juice barrel inner wall coatings. And for the previous supply of Shaanxi, Shanxi, Henan, Ningxia and other major barrel companies successfully upgraded products. After the product upgrade, the company solved the environmental problems such as VOC emissions, improved the pungent and astringent smell of the previous oil paint, and improved the working environment of the workshop staff. Our company has perfected the difficulties in the construction process of water-based paints. The water-based paints developed have surpassed the chemical resistance of oil-based paints on steel drums, improving the paint-off phenomenon caused by frictional collision during transportation, making each performance superior to oil. coating. It is new latest design 1800W Hair Dryer. it comes with hot and cool function and also comes with hi and low function . so it have dual switch control. that is not comes with other.in today's day and age, it comes with good quality and low price. so all can afford it. 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