Advantages and disadvantages of powder coating and coating technology

Coating and coating technology as a resource-saving, energy-saving, low pollution and high efficiency of labor production and get the attention of all countries In the 1970s, some people even predicted that the traditional coating would be gradually replaced by powder However, more than 20 years of history has proved that although the powder coating has many advantages and the production growth rate is faster than other types of coating, it also has some disadvantages Up to now, it accounts for less than 5% of the total coating production 1、 The advantages of coating and coating technology (1) powder coating does not contain organic solvent and water, and VOC is equal to zero, which not only saves a lot of resources, but also avoids the atmospheric pollution caused by photochemical reaction and toxicity, as well as the problems of wastewater treatment, etc., so it is an ideal coating variety in line with the requirements of environmental protection (2) It can avoid the harm of organic solvent to the operator's health and the fire hazard in production, storage and transportation (3) In powder coating, powder coating circulates in a closed system, and the overflowing powder can be recycled, which saves resources The utilization rate of the coating is more than 95% If the recovery efficiency of the recovery equipment is good, it can even reach 99% (4) In powder coating, the thickness of coating film is easy to control The thickness of one coating can reach 50-500um (when the coating is cold sprayed, the thickness of coating film is 100um), which is equivalent to the thickness of several to more than ten coats of solvent coating It can reduce the number of coats, improve labor productivity and save energy It also saves the waiting area for the workpiece stacking between each coating (5) The molecular weight of resin for powder coating is larger than that of solvent coating, so the physical and mechanical properties and chemical resistance of the coating are better than that of solvent coating (6) Powder coating does not need very skilled operation technology, easy to master, thick coating film is not easy to produce sagging and other defects, the implementation of automatic assembly line coating (7) The coating is in powder state, so it does not need to adjust the viscosity with seasons like solvent based coating, and it does not need to be placed for a period of time after spraying, so that the solvent evaporates and then enters the oven, which can save the coating time In the construction site, it can greatly reduce the stacking area of workpieces to be baked 2、 The disadvantages of powder coating and coating technology (1) the requirements of manufacturing powder coating equipment are higher, which is much more precise than solvent or water-based coating equipment, and the manufacturing cost is also higher (2) Due to the complexity and precision of the equipment, the powder coating is not suitable for the production of multi varieties and multi colors, so it is difficult to change varieties and colors (3) Powder coating equipment needs to be equipped with powder coating recovery device, which is not as simple as solvent coating construction At the same time, dust explosion prevention and other issues should be considered, so the equipment investment is large (4) The softening point of resin for powder coating is generally above 85 ℃ In the process of manufacturing powder coating, the melting extrusion temperature is 10 ℃ higher than the soft point, and the melting leveling temperature is at least 30-40 ℃ higher than the softening point In this way, the baking temperature of powder coating is mostly above 150 ℃, and the baking temperature is high, which is not suitable for plastics with poor heat resistance The coating of wood, paper and other base materials is not suitable for the coating of solder parts, electronic components and other heat-resistant articles (5) Due to the problems of coating equipment and baking temperature, the coating equipment or coating line originally used for coating solvent based coating or water-based coating cannot be directly used for coating powder coating See table 1-16 for coating characteristics of powder coating and solvent type solvent Table 1-16 coating characteristics of powder coating and solvent coating: powder coating and coating, solvent coating and coating, coating thickness of primary coating / um 50-500 10-30 thin coating is difficult and easy Thick coating is easy, hard to apply, automatic coating line is easy, recovery and reuse of general spray coating are OK or not Project: powder coating and coating; solvent based coating and coating film performance; no air pollution caused by general solvent Fire hazard caused by solvent, no toxicity caused by solvent, no dust pollution, but little self inspection There is dust explosion problem, but it's not big There's no need to check the efficiency of coating labor There's no need for general special coating equipment Proficient in production and operation technology, no need for color change and color mixing of paint, trouble in simple solvent waste, no inspection Convenient transportation and storage of coatings