There are three commonly used production methods for metal powder coatings, namely extrusion, dry mixing and bonding.
Extrusion method The extrusion method is to mix the metal pigment and other ingredients in the formula, extrude together, and then crush and sieve to obtain the finished product. This method can uniformly coat the metal pigment particles in the resin powder. The metal powder produced by this method can be sprayed with a corona electrostatic gun or a friction gun, has almost no window frame effect, can be sprayed into grooves, and can be recycled. But usually the metal powder produced by this method tends to be black or gray, and the shiny metallic effect cannot be obtained.
Dry mixing method The dry mixing method is to mix the base powder (ordinary powder) and metallic pigments under slow and low shear conditions. The dry blending method is simple and low in cost. At present, most metal powder coatings in the Chinese powder coatings market are produced by dry blending. The most prominent problem in the production of metal powder coatings by dry mixing is the instability of color. Secondly, the use of recycled powder will cause the loss of metal effects, and it is difficult to spray workpieces with complex shapes. In the production of metal powder coatings by dry mixing method, the addition of metal pigments is limited by the sprayability, generally at 1.5-6%, if it is too much, it will not be easy to spray. Bonding method (Bonding) is to stick the metal pigment particles to the surface of the powder particles. It is desirable that all metal particles adhere to the surface of the foundation particles and do not separate during application. But in fact, some metal particles do not stick well or do not stick to the surface of the powder particles, and these metal particles can cause problems.
Generally, metal powder produced by bonding method contains less ultrafine powder than metal powder produced by dry mixing method, which is better for recycling, and the color is more stable after recycling. Less window frame effect, easier to spray into grooves.
Bonding is a new technology for producing metallic powder coatings. Through the bonding technology, the metal pigment and the base powder particles are tightly bonded together, so that the metal pigment will not be separated from the base powder during spraying, avoiding the blooming and unevenness caused by the general dry mixing method.
The main advantages of metal powder coatings produced by the bonding method are: good color stability, good sprayability, and can be recycled. In addition, Bongding technology can make the addition of metallic pigments higher (1%-20%), and get more and better metallic glitter effects. Quality control Quality control is a very critical step. Whether it is used smoothly and stably at the customer's site needs to be controlled before leaving the factory. Through continuous experience summarization, a complete set of quality control methods has been formulated.