Spray powder coating is a surface treatment method that involves spraying plastic powder onto parts. It is also commonly referred to as electrostatic powder coating, and its processing technology has been widely adopted internationally as a decorative technique for metal surface treatment since the 1980s. Compared to ordinary paint surface treatment, this technology offers advantages such as advanced process, energy efficiency, safety, reliability, and vibrant colors. Therefore, it is often applied in the fields of light industry and household decoration. Its working principle involves charging plastic powder through high-voltage electrostatic equipment. Under the influence of an electric field, the paint is sprayed onto the surface of the workpiece, and the powder is evenly adsorbed onto the surface, forming a powder coating. The powder coating is then leveled and cured after high-temperature baking, and the plastic particles melt into a dense final protective coating with various effects, firmly adhering to the surface of the workpiece. Spray powder coating products are mostly used for indoor cabinets, with a flat or matte finish. Spray powder coatings mainly include acrylic powder and polyester powder.
Spray powder coating refers to a treatment process for industrial metal surfaces. Powder coating, a new type of solvent-free 100% solid powder coating, is divided into two major categories: thermoplastic powder coating and thermosetting powder coating. The coating is prepared by mixing specially formulated resins, fillers, curing agents, and other additives in a certain proportion, and then through processes such as hot extrusion and crushing and screening. They are stable in storage at room temperature, and after electrostatic spraying or fluidized bed dip coating, they are heated and baked to melt and solidify, forming a flat, glossy, permanent coating film for decoration and corrosion protection purposes. It is commonly used in clothing display props, shelves, cabinets, workbenches, logistics storage and transportation equipment, etc.
The difficulty and technical key to achieving ultrafine powdering of powder coatings lies in solving the fluidization problem of ultrafine powder particles. The average particle size of conventional powder coatings is 30-50 microns, and powder particles of this size have good fluidization properties, which means they can be uniformly dispersed and suspended under airflow, enabling smooth electrostatic powder coating. However, when the particle size becomes smaller and turns into ultrafine powder (with an average particle size less than 25 microns), the mass of the powder decreases significantly while the surface area increases exponentially, greatly increasing the actual adsorption force between powder particles. This leads to the tendency of ultrafine powder particles to clump and agglomerate, resulting in poor fluidization performance. These are the natural properties of ultrafine powder.
