Electrophoresis lacquer liquid precipitation treatment.

 1. Electrophoresis lacquer precipitation is not only an important sign of its stability, but also an important factor affecting the quality of product coating and production costs.
Countermeasures for the causes and factors of electrophoresis lacquer precipitation:
(1) to buy qualified coatings, before use, should first go through the relevant tests, including the determination of paint precipitation
(2) improve the process, solve the problem of circulation and mixing of paint liquid
(3) Strict production management
2. The main factors affecting the precipitation of electrophoretic lacquer
2.1 magazine ions
the entry of same-sex or opposite-sex magazine ions is bound to react with the paint charged resin and form some ensents or sediments, the formation of these substances destroyed the original electrophoretic properties and stability of the coating. The sources of impurity ions are as follows:
(1) Impurity ions inherent in the coating itself
(2) Impurities
(3) when equipped with electrophoretic lacquer liquid before treatment of impurities that are not thoroughly brought in
(4) pre-treatment is unclean when flushed with water Impurities
(5) impurity ions
(6) anodes dissolved and impurity ions
from the above analysis, the pre-coating quality should be strictly monitoredThis is not only necessary to improve the quality of the product coating, but also to maintain the stability of electrophoresis lacquer is also very important. At the same time, from the above analysis can also show that the water quality of pure water and phosphate solution selection (matching) is how important
2.2PH value
different electrophoresis coatings on the PH value of the adaptation range is also different. Cation electrophoresis coating, PH value is generally not greater than 7, resulting in electrophoresis liquid PH value is too high is mainly before and after the coating of the last water flushing into and alkali substances mistakenly into the electrophoresis tank.
2.3 solvents
in order to make electrophoresis coatings have good dispersion and water solubility, the original paint often contains a certain proportion of organic solvents. In normal production, the consumption of organic solvents is supplemented in time with the repaint work. However, if the production is abnormal or the temperature is too high caused solvent consumption (volatile) too fast and can not be replenished in time, to reduce its content below the lower limit, the working lacquer liquid will also change, it makes the coating film thin, in severe cases, will also make the resin in the paint liquid condensation or precipitation. Therefore, in the process of tank fluid management, managers should always pay attention to the changes in solvent content in electrophoretic lacquer liquid, if necessary, solvent content analysis, timely replenishment of accelerated amount of related solvents.
3, temperature
a variety of coatings to the temperature also has a range of adaptation. An increase or decrease in temperature can speed up or slow down the electrical deposition process, thickening or thinning the coating film. If the paint temperature rises too high, the solvent evaporates too fast, easy to cause the paint liquid condensation precipitation. In order for the paint temperature to always be in a relative "constant temperature state", a thermostat is required.
4, solid content of the paint liquid not only affects the quality of the product coating, but also affects the stability of the lacquer liquid a factor. If the solid part of the lacquer liquid is too low, its viscosity is reduced, which promotes the precipitation of the lacquer liquid. Of course, too high solid points are not enough to take, because too high, coating after swimming belt increased, loss increased, reduce the utilization rate of paint, so that the cost increased.
5, cycle stirring in the production process, management personnel must always pay attention to the electrophoretic lacquer liquid circulation stirring is good, some instrument pressure (such as filters, ultrafiltration) is normal. Ensure that the lacquer liquid cycles 4-6 times per hour, the bottom lacquer flow rate is about 2 times the flow rate of liquid lacquer liquid, do not make the electrophoresis tank form a stirring dead angle. Do not stop stirring in non-exceptional circumstances.
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