Powder coatings have the tendency to caking at a certain temperature, which is mainly due to the softening of the resin and leveling agent and other materials in the coating when they encounter heat. Thermosetting powder coatings are organic polymers with low molecular weight of resin.
This kind of resin itself has a physical property, at a lower temperature, it will appear hard and brittle glass state, when the temperature rises to a certain degree, the resin will turn into a certain elasticity, and produce a state of adhesion, below this temperature, the resin and return to the glass state, the resin of the glass state and viscoelastic state of the mutual transformation of the temperature is called the resin glass transition temperature.
Powder coating powder input air pressure should not be too large, generally controlled at 0.5-1.5kg/cm2 is good. Too much air pressure will cause poor pattern clarity or produce some pockmarks. Electrostatic voltage should not be too high, generally controlled at about 60-70Kv. The voltage is too high, will make the powder attached to the surface of the workpiece rebound phenomenon of pockmarks. Defects such as poor leveling.
Powder spraying should pay attention to ensure the thickness of the coating film, generally control between 70-100μm can be conducive to the formation of obvious patterns and larger patterns, thin coating film is not obvious patterns, and patterns are also small, at the same time will appear pockmarked bottom and other defects.
Our powder coatings are sold all over the country, and some of our products are exported to overseas. The heavy metal content of our powder coatings is much lower than the testing standards of developed countries in Europe and America, and we have won praise from customers at home and abroad.