Low Cost Silicon And Silicon Dioxide Powder

QX-20 Matting Agent For Economic Coating

What is silica matting agent that is added into coating?

Pigments or fillers are added to the paint, evenly distributed in the paint film and form a micro-rough surface. The larger the surface particles,

the greater the degree of micro-roughness, and the lower the gloss. Sometimes light calcium carbonate or talcum powder is used in the production

of matte paint, and the amount is large, which often exceeds the critical pigment volume concentration of the paint and deteriorates the physical

properties of the film, such as stratification and hard precipitation. The use of matting agents can avoid this phenomenon. Commonly used matting

agents are divided into two categories: organic and inorganic. Inorganic matting agents are mainly white carbon black matting agents, whose

chemical composition is silicon dioxide, and are divided into two types: surface treated with organic matter and untreated. Now we focus on the

application of white carbon black matting agents in paints.

1. White carbon black matting agent: Natural silicon dioxide is ground to produce quartz sand (powder), which has a high impurity content and is

mainly composed of silicon dioxide. It cannot be called white carbon black and has no matting properties. It can only be used as a filler in coatings

and has no matting effect. The white carbon black matting agent used in coatings is mainly synthetic silicon dioxide, which is divided into two

categories: gas phase white carbon black and precipitated white carbon black. Its microstructure is amorphous or glassy.

Precipitation method synthetic white carbon black uses quartz sand as the main raw material, which is melted with sodium hydroxide or sodium

carbonate in a kiln at high temperature and then post-treated. Gas phase white carbon black is produced by hydrolysis of silicon tetrachloride vapor

in a hydrogen-oxygen flame. Compared with natural silicon dioxide, the silicon dioxide of white carbon black is of high purity, high inertness, and

UV resistance. The refractive index of amorphous silicon dioxide is 1.46, which is similar to the refractive index of many resins in the coating industry.

Therefore, amorphous white carbon black can be used as a matting agent in coatings and has good optical properties.

2. Matting mechanism of white carbon black matting agent: The varnish film without matting agent is in a mirror film leveling state. When light reaches

the mirror film surface, part of the incident light is absorbed and part is reflected. The reflected part makes the film glossy. The paint film containing white

carbon black matting agent, the white carbon black particles evenly distributed in the paint film form a micro-rough surface.

From the scanning electron microscope photo of the coating cross section, it can be clearly seen that the matting agent particles are evenly distributed in

the coating film. When the incident light reaches the uneven surface of the paint film, diffuse reflection occurs, that is, scattering occurs to produce low-gloss

matte and matte appearance. The best matting effect can be obtained by using a white carbon black matting agent with high porosity, optimal particle size

distribution and suitable surface treatment.

The following specification parameters will be stated on our Certificate of Analysis.

Anticorrosion Pigments, Inkjet Receptive Coating, Matting Agent