Application of ultrafiltration system in electrophoretic coating
electrophoretic coating is a special film forming method. In order to improve the corrosion resistance of the inner cavity and weld surface of the automobile body, Ford Motor Company of the United States began to study the electrophoretic coating method in 1957, and built a test production line (anodic electrophoretic coating method) for swimming coated wheels in 1961, which was successfully used in the coating of the automobile body in 1963. Electrophoretic coating is highly valued by the coating industry because of its high efficiency, high quality, safety, economy and many other advantages. With the development of new coatings and the progress of coating technology, especially the successful development of cathodic electrophoretic coatings and cathodic electrophoretic coating technology in 1977, electrophoretic coating technology has been rapidly developed and popularized in automotive, household appliances and other industries
the coating of automobile and its parts is one of the links that produce the most three wastes in the process of automobile manufacturing. With the increasing voice of global environmental protection, the corresponding environmental protection laws and regulations have been formulated and issued all over the world. Therefore, reducing the discharge of coating sewage, reducing the coating cost and improving the coating quality have become the main topics of electrophoretic coating technology research and development. The application of membrane technology in electrophoretic coating can effectively solve this problem, and its process flow is shown in the figure
process flow chart of the application of membrane technology in electrophoretic coating
electrophoretic paint process can evenly and flawlessly coat the workpiece with sharp edges, or the workpiece that cannot be touched at this time by pressing the confirm key and cavity. The electrophoretic coating process includes the dispersion of charged paint particles in the water base, the electrophoretic deposition on the conductive metal workpiece, and the excess paint adhered to the workpiece after coating is removed by washing. The water used for flushing is the permeate filtered by the ultrafiltration system integrated with the paint tank, and this flushing medium returns to the paint tank from the downstream flushing area. The volume in the paint tank always remains the same, forming a closed-circuit circulation system of multi-stage flushing. Therefore, no waste water will be produced and little deionized water will be used for flushing
the function of ultrafiltration system of electrophoretic paint is:
1. Maintain the stability of tank solution system and improve the quality of paint film. In the continuous production process, various impurity ions are inevitably brought into the paint solution system, and some impurity ions will also be generated in the electrophoresis film-forming process. The existence of impurity ions will have adverse effects on the electrodeposition, stability and film quality of the paint solution, so its content must be strictly controlled and kept within a certain range. The conductivity of the electrophoresis tank solution and the impurity ions, organic solvents, small molecular resins in it are controlled by the discharge of ultrafiltration dialysate, so as to ensure the continuous and stable operation of production
2. Recover the electrophoretic coating to the greatest extent, improve the utilization rate of the coating, and reduce the amount of clean water after electrophoresis. The ultrafiltration solution of the ultrafiltration system can be used to fully wash and remove the electrophoretic coating adhered to the coating, forming a closed-loop system of multi-stage washing, which will increase the recycling rate of the coating from 70% - 80% to more than 95%
3. Minimize the production of coating wastewater and greatly reduce the amount of deionized water. The waste water treatment cost is saved and the production cost of the production system is reduced. Tower crane performance test gb/t5031 ⑼ 4
the surface and geometry of the workpiece coated by the electrophoretic coating process determine the amount of flushing medium required, which is also the basis for designing the production capacity of the ultrafiltration system. Generally, ultrafiltration can carry out complex data analysis. The system is designed to provide 1.2 ~ 1.5L ultrafiltration dialysate for washing per square meter of coating area, and consider the margin of 3 ~ 5% design coefficient. As the core component of the ultrafiltration system of electrophoretic paint, the ultrafiltration membrane continues to develop with the update of electrophoretic coating technology, which is reflected in the continuous optimization of membrane materials and component design, so as to adapt to the development of new coating technology, and meet the needs of coating manufacturers for long service life and high production capacity of the ultrafiltration system
in the selection of ultrafiltration membrane, Maynard electrophoretic ultrafiltration membrane is made of nadir membrane, which has a wide pH tolerance range and high thermal stability. This membrane is composed of a permanently hydrophilic polymer specially developed for this purpose, which can maintain its hydrophilicity even after a long time of use and frequent cleaning
in terms of membrane module form selection, Maynard chose spira-cel, a spiral wound membrane with high filling density. The capacity of ultrafiltration membrane module is mainly expressed by the ultrafiltration filtrate permeability, which mainly depends on the effective membrane area. In the electrophoretic coating process, coiled ultrafiltration membrane has become the most economical ultrafiltration option with its largest membrane area, smallest component volume and smallest component investment
in terms of ultrafiltration of electrophoretic paint, Maynard company is a professional manufacturer of membranes and coiled membrane components. Its membranes and coiled membrane components are not only used for cathodic electrophoretic painting, but also for anodic electrophoretic painting. In the paint industry, Maynard's customers include Audi, BMW, Porsche, etc. In addition, Maynard established a subsidiary in China in early 2006 to ensure further product and service support for customers in the Asia Pacific region. (end)
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