Matting powder is a kind of coating additive, easy to disperse, powdery. Common matting powders include white carbon black and talc. The matting powder has the characteristics of “direct application” and is easy to use. Its extinction principle is not limited to one:
In order to reduce the gloss of the coating film, conventional matting agents include ultrafine silica, talc, aluminum stearate, calcium stearate, and low molecular weight thermoplastic resins. To get the matting effect, you can use the following methods:
1. The powder coatings with different curing speeds are mixed by the dry mixing method, and the gloss of the obtained coating film is obviously lowered to play a matting effect. Due to the rapid curing of the highly reactive powder coating, the slower curing of the continuous phase of the resin and the reaction are hindered, and the final cured coating loses its luster. Although this method is effective, it increases the manufacturing process and costs.
2. Add thermoplastic resin. A cellulose powder is added to the epoxy powder coating, and a fine powdery low molecular weight polyethylene or a polypropylene resin is added to the polyester powder coating to obtain a matte powder coating. The gloss of the coating film is affected by the manufacturing conditions. Since the addition of the thermoplastic resin will affect the storage stability of the powder coating, the amount of addition is limited to 23% of the amount of the resin.
3. Use a special curing agent with matting effect.
4. Add filler with matting effect. The addition of fillers such as ultrafine silica and talc causes a significant decrease in gloss. In particular, the particle size of the filler has a great influence on the gloss of the coating film. The larger the particle size, the lower the gloss. It is to be noted that increasing the amount of the filler causes a decrease in the flatness and mechanical strength of the coating film. In the epoxy powder coating, the effect of calcium carbonate particle size on the gloss of the coating film is shown in the table. The addition of ultrafine silica and kaolin to acrylic, polyester powder coatings gives matt coatings.
In addition to this, a matte coating can be obtained by adding a wax such as polyethylene paraffin or hydrogenated castor oil.
Anticorrosion Pigments, Inkjet Receptive Coating, Matting Agent
