Electrostatic spray is a commonly used spray method. The surface of the workpiece sprayed with electrostatic spray is smooth, the coating is thick, and the defects of particles are not easy to occur. Moreover, the adhesion of the surface coating film is good, and the corrosion resistance and weather resistance are excellent. Electrostatic spray applications are becoming more widespread. In the electrostatic spray process, we sometimes spray some products with corners, and these corners are not easy to powder. How can we improve this situation? Mainly from the following aspects. To improve the overall chargeability of the formulation, it mainly includes the modification and addition of resin, filler and auxiliary agent. The analysis of these two aspects from the powder point is an important factor affecting the powder rate of the sprayed product.
1. Powder coatings are mainly composed of high molecular compounds such as epoxy and polyester resins. These compounds have a high dielectric constant and thus have a strong electric field force in the electric field. If only pure resin is used in the formulation, the powder is applied. The rate is good. However, due to the high cost of the price, this method is generally not used. Powder manufacturers need to add fillers to reduce the cost of materials in order to compete in their own market, and control the appropriate ratio of pigment to base, in which fine fillers are added, in the test, such as ultrafine Barium sulfate can increase the powder rate on the dead angle. 2. Now our factory basically achieves the increase of the powder rate on the dead corner of the powder by adding a charging aid to the powder formulation. Mainly divided into two; power-up agents and antistatic agents. The main component of the electrification agent is an organic amine salt with a charged group, which increases the charge amount of the powder particles during spraying, and leaks the charge on the surface of the workpiece in time, thereby increasing the powder rate on the upper dead angle, thereby overcoming the electrostatic shielding effect.
The antistatic agent is different from the general amine-based charged agent, so that the powder has good triboelectric charging properties. It has its own charged functional group. In the powder coating, it captures the negative electric charge on the negative ion in the ionization field, weakens the Faraday effect power line in the dead angle of the groove, and thus increases the powder rate on the dead angle.
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