Influencing factors of powdering rate of powder anticorrosive coating B

24-02-2021

Increase resin content. Among the components of powder coatings, resin, as a polymer compound, has the highest dielectric constant, while pigments and fillers have lower dielectric constants. If there are more substances in powder coatings with higher dielectric constants, the powdering rate will be increased during spraying, but at the same time it will also increase the cost, requiring coating companies to configure the resin content according to customer needs.

Use pigments and fillers reasonably. The fineness and dispersibility of pigments and fillers have a great relationship with the powdering rate. Pigments and fillers with relatively uniform fineness and good dispersibility can increase the powdering rate once.

An indispensable conductive aid. Conductive additives can make the powder particles carry more charges, so it is necessary to pay attention to the addition of conductive additives during formulation design. Especially for the dead corners of the groove and other parts, due to the weak Faraday effect power line, the powder particles with more electric charge can reach the surface of the workpiece by themselves, thereby improving the powder loading rate of these parts.

Spraying process conditions. Due to the difference in climate between the north and the south, and the different temperature and humidity characteristics in winter and summer, they will more or less affect the powdering rate. Therefore, it is necessary to design a relatively stable temperature and humidity, a cleaner spraying environment, a more stable voltage, and a more suitable spraying. Spacing, proper air pressure, good workpiece grounding, etc.

Suitable spray gun. The powder rate is related to the type of spray gun, process parameters, workpiece shape and spraying method. Many companies only pay attention to the maximum powder output of the spray gun. In fact, the increase in the compressed air output and air pressure can increase the powder output. However, whether the high-voltage electrostatic generator can charge so much powder is a problem. As far as the spray gun is concerned, the dense powder will block each other's way of charging, so that the following powder cannot be charged, or only charged to a small amount of charge. From the point of view of the spraying process, when the coating surface reaches the electrostatic balance, the powder particles and the particles on the coating surface will repel each other, and even fall off due to the opposite movement of the ionization, and be recycled by the recycling equipment. Therefore, the amount of powder should be measured according to the charging ability of the spray gun, and more consideration should be given to whether the powder is fully charged, and it should be determined according to the shape of the sprayed workpiece and repeated experiments.

In addition, if the workpiece has grooves, grooves, sharp corners, small holes, etc., Faraday shielding phenomenon will occur. The sprayed coating will be very thin and leaky. Only the use of artificial large amount of powder spray will reduce the amount of powder recovery. Will increase simultaneously


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