Common knowledge of coating: depth analysis of four factors affecting the quality of electrophoretic coating film

Core tip: in recent years, due to the advantages of high corrosion resistance, weather resistance and decoration, the electrophoretic coating technology has made rapid development in the automotive paint industry However, China's electrophoretic coating industry started late, and the spraying related technology is not mature, which often leads to quality problems The following new coating mesh small series on the impact of electrophoretic coating four basic factors and you to discuss Electrophoretic coating is a kind of coating developed for electrophoretic coating process It is a kind of water-soluble or water emulsion coating It can be dissociated into charged macromolecular ions in water Under the action of DC electric field, it moves to the opposite polarity of itself Shenyang steel structure fireproof coating construction expert punde Building Fire Engineering Co., Ltd Recommended introduction: since its establishment, Shenyang punde Construction Fire Engineering Co., Ltd has cultivated a group of professional construction teams with excellent equipment, rich experience and serious responsibility with advanced and scientific management methods and strict engineering quality assurance and after-sales service system It has undertaken a number of fire system installation projects, which has been praised by customers Every idea and special requirement of you will be fully considered by us and fully realized in the construction technology, which will become the cornerstone of our successful long-term development We are looking forward to your invitation, to provide you with quality services and high-quality technical support! All construction coatings have passed ISO9001 Home of coatings: in recent years, due to the advantages of electrophoretic coating, such as high corrosion resistance, weather resistance, decorative properties, etc., electrophoretic coating technology has made rapid development in the automotive paint industry However, China's electrophoretic coating industry started late, and the spraying related technology is not mature, which often leads to quality problems The following new coating mesh small series on the impact of electrophoretic coating four basic factors and you to discuss Electrophoretic coating is a kind of coating developed for electrophoretic coating process It is a kind of water-soluble or water emulsion coating It can be dissociated into charged macromolecular ions in water Under the action of DC electric field, it moves to the polar plate (coated object) opposite to its polarity, and precipitates on its surface In the process of electrophoretic coating, the factors affecting the surface quality of the film are the solid content of the bath solution, the electrophoretic voltage, the electrophoretic time and the pH of the bath solution First, the influence of the solid content of the bath solution on the film thickness and appearance the solid content of the bath solution should be kept to a certain extent, not too high or too low If the solid content of the bath solution is too low, the penetration is reduced, the paint film is thin, the covering power is poor, and the anticorrosion performance is poor When the solid content of bath liquid is too high, the speed of electrodeposition is accelerated, orange peel is easy to be produced on the surface of paint film, and the smoothness is reduced When it is too high, the paint will be taken away by the coating, causing serious loss of paint After a long-term test, it is the best to control the solid content of electrophoresis bath liquid at 5% - 6% Secondly, the effect of electrophoresis voltage on the thickness and appearance of paint film in the process of electrophoresis, when the voltage is low, the amount of electrodeposition is small, and the paint film is thin; when the voltage is increased, the electric field force is strong, the swimming force is high, the amount of electrodeposition increases quickly, and the thickness of paint film increases However, if the voltage is too high, the spot decomposition reaction will be intensified, a large amount of gas will be produced on the electrode surface, the thickness of the paint film is too large, the film is rough, there are many bubbles and pinholes, on the contrary, the hardness of the paint film will be reduced, and the paint film will fall off after baking Generally, the selected voltage is about 120V Third, the effect of electrophoresis time on the film thickness and appearance During the electrifying process of electrophoretic coating, with the extension of electrophoretic time, the paint film gradually thickens, because the coated workpiece is exposed at this time, the electric field strength is large, and the resin particles have strong electrophoretic penetration However, due to the non conductivity of the paint film formed, when the film thickness increases to a certain value, further prolonging the electrophoretic time, the film thickness decreases instead, resulting in the phenomenon of back dissolution, and the appearance of the paint film changes Poor, a little orange peel Generally, electrophoresis time is best controlled between 80-100 seconds Fourth, the influence of bath pH on the appearance of the paint film in the process of electrophoresis, the ammonia ion produced in the bath will increase the pH value, when the pH is about 7.8, the appearance of the paint film is better, and there are few pinholes; when the pH is more than 8.4, there are more pinholes When the pH value is too low, the dispersion of resin is reduced, the electrophoretic paint film is rough, and orange peel appears in serious cases Usually, ultrafiltration system is adopted in the factory to make small molecules discharged through the ultrafiltration membrane, while large molecules return to the electrophoresis tank, so as to control the pH value Generally, it is best to control pH value at 7.6-8.1 Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,