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What is Silica Matting Agent?

Silica Matting Agent has good optical properties because its refractive index is close to that of most resins used in the coating industry (1.46).

It is currently widely used in coatings and has become the first choice for high-end coating matting agents. 

The matting agent used in coatings, paints, inks, etc. in the early days was Fumed Silica, which has been gradually replaced by precipitated

silica due to its high price. For a silica matting agent with a given particle size, its matting efficiency increases with the increase of pore volume.

For a given coating and coating film thickness, the matting effect is best when the matting agent particle size corresponds to the coating dry

film thickness. The narrower the frequency band of the particle size distribution, the higher the matting efficiency. In this paper, the precipitation

method was used to prepare the silica matting agent. 

On the basis of previous studies, the approximate range of operating parameters such as reaction temperature, feeding time, holding time,

stirring speed and sulfuric acid acidification amount for obtaining the silica matting agent with appropriate oil absorption value, particle size

and large pore volume was determined. The ideal reaction conditions were determined through orthogonal experiments, and the influence

of various factors on the median diameter and oil absorption value of the generated silica was studied. The structure and properties of the

prepared silica were characterized. The purpose was to synthesize a silica matting agent with large pore volume, suitable particle size and

oil absorption value, and good compatibility with coatings.

What does the dispersion quality of matting agent depend on?

When using matting agent, it is necessary to measure the fineness or Hegman value of the coating to obtain dispersion information. Since there

is no rule for comparison with commonly used matting agent coating systems, the particle size value can sometimes be defined as an acceptable

method. The fineness is usually greater than 25 microns, such as silica matting agent. Reducing the particle size value reduces the matting effect

and increases the gloss.

There are many benefits to painting with matting agent added.

After the paint is applied to the surface of the object, it is cured into a film by the volatilization of the matting agent solvent (for solvent coating).

The coating formation process is very important for the surface roughness and gloss of the coating. In the wet film stage, the evaporation rate of

the solvent is controlled by the diffusion of the solvent on the coating surface. When the evaporation rates of the various components of the solvent

are not very different, a high gloss surface can be obtained.

On the contrary, when the evaporation rates of the various components of the solvent in the wet film stage are different, the polymer molecules

tend to curl or even precipitate into particles or agglomerates of different sizes, and the coating surface is uneven. In the dry film stage, the solvent

volatilization rate is mainly controlled by the diffusion of the solvent in the overall application, and it also affects the roughness of the coating surface.

In addition, when the matting powder coating is formed, as the solvent evaporates, the coating will become thinner and shrink, and some

suspended heavy particles in the coating will be rearranged on the coating surface, resulting in an uneven coating surface.

Highly dispersible matting powder has a lot to do with its surface area

Like traditional matting powder, when the surface area of ​​high-dispersion matting powder is higher, the reinforcement performance is also better.

When the surface area is larger, the reinforcement performance is better, but the processing performance is poor. The reinforcement performance

of high-dispersion matting powder with the same surface area is better than that of traditional matting powder.

When the structure of the matting powder is higher, the dispersibility is good and the vulcanization rate is also higher. The phenomenon of good dispersibility when the structure is higher can explain that the high-structured matting powder has more pores, and the polymer will penetrate into

the pores at the beginning of mixing. Then, when the attachments are broken into polymers by the mixing shear force, they will be better dispersed

in the polymer. The low-structured traditional matting powder is compacted at the beginning of mixing and difficult to disperse.

Anticorrosion Pigments, Inkjet Receptive Coating, Matting Agent