The Role of Oxidized Wax in Powder Coatings

 Powder coatings, as the name implies, are powdery coatings. According to different film-forming substances, they are mainly divided into thermoplastic powder coatings and thermosetting powder coatings. The former has limited application fields due to poor coating gloss, leveling properties, and adhesion to metals. The latter is mainly used in coating and finishing fields such as automobiles and electrical appliances.

    Next, I will mainly explain the role of oxidized wax in powder coatings:

    Conventional powder coatings contain 50-60% binders (resins and hardeners), 40-50% pigments and fillers, and 1-2% additives. These components are mixed in a mixer of appropriate size to obtain the so-called base compound, which is then extruded. During this process, the raw materials melt and fuse into a uniform mass. After a few seconds, the material passes through the extruder at a temperature of approximately 100°C. During extrusion, oxidized wax acts as a lubricant to reduce pressure and increase output.

    Oxidized wax also helps improve the wetting ability of the resin mixture on pigments and fillers.

    The paste is pressed by a pair of cooled rollers and cooled on a cooling belt. After cooling and crushing, the material is ground to the particle size desired by the customer. Since oxidized wax is crystalline, it increases the efficiency of the grinding stage.

    Powder coatings are fluidized or mixed with compressed air so that they can be pumped into the spray gun and then charged with electricity. During application, oxidized wax reduces the risk of caking and prevents rapid wear of the nozzle.

    During heating, the powdered wax particles cure and fuse into a hard solid coating, which improves the surface hardness, scratch resistance, abrasion resistance, and gloss of the final film.

    Oxidized wax powder also acts as a flow aid. It reduces the viscosity of the system, thereby adjusting the resin flowability to achieve a more uniform surface and higher gloss.

    The addition amount of oxidized wax in powder coatings varies between 0.2% and 1.5%.