What is matting?
The flat paint film has a more elegant and gorgeous appearance, especially for interior paints, such as furniture paints, where strong gloss can irritate the eyes. Matting requires roughness on the surface, but the roughness observed by the naked eye will affect the appearance of the paint film, so a fine rough surface should be formed.
Roughness can be formed by the shrinkage of the paint film caused by the volatilization (or reaction) of the solvent when the paint film dries, or it can be formed by adjusting the rheology of the paint, increasing the volume concentration of the pigment or selecting the type of pigment, and adding a matting agent to the paint. form. Matting agents mainly include fumed silica and paraffin or polyolefin surface powder.
The particle size of fumed silica is extremely small (average particle size 0.012µm, particle size range 0.004~0.17µm), and the surface is porous, easy to float on the surface. When the paint is just coated, the paint film is glossy. After the solvent evaporates, the paint film becomes thinner, and silicon dioxide floats on the surface of the paint film to form a fine rough surface before it becomes flat. Wax or polyolefin surface powder has low density and is easy to float on the surface of the paint film to achieve a matting effect. If the surface of SiO2 is treated with paraffin, the paint film can have a good feel. Wax floating on the surface of the paint film not only increases the roughness of the paint film, but also has a low molar refractive index.
With a small amount of fumed silica, the paint film can have both low gloss and high transparency. As the solvent evaporates from the paint, the siO2 particles keep moving and reach the surface of the film, making the viscosity higher, and as a result, the concentration of fumed silica on the surface of the paint film is higher than the average concentration in the paint film, at a relatively low PvC Gloss is reduced.
What is flash?
Glitter pigments are effect pigments, and effect pigments are short for angle-dependent effect pigments. This kind of paint is usually called metallic flash paint in our country.
Flash paint consists of film formers, transparent color pigments (or dyes), metallic flash pigments and solvents. After this kind of coating is coated on the substrate, the pigment flakes can be aligned in parallel in the process of solvent volatilization. The metal sheet has a high ability to reflect light. Under the irradiation of incident light, due to the different optical paths of the reflected light at different angles, some of the metal sheets are reflected multiple times before being emitted from the surface, and some are only reflected once. For one thing, the light intensity in different directions is different. When looking down (small incident angle), the reflected light is bright but not saturated, because the optical path is short, the light absorption is low, and the emitted light contains more white light components. When viewed from the side (large incident angle), the reflected light is weak, but the chroma is saturated and bright, because the optical path is long, the light absorption is high, and the emitted light contains low white light components.
When observed perpendicular to the surface of the paint film, the paint film shows a strong complexion; when observed parallel to the paint film, the paint film appears the complementary color of the complexion, that is, colors of different lightness, purity, and hue can appear with different viewing angles The phenomenon is called the angle-dependent effect. This is caused by the different scattering and reflection of incident light by effect pigments.
Effect pigments can be divided into three parts: one is metal flake pigments, such as aluminum powder; The third is ultra-fine transparent metal oxides, such as ultra-fine TiO2, ultra-fine MgO, ultra-fine Sb2O3, ultra-fine barium sulfate, ultra-fine ZnO, etc., among which ultra-fine TiO2 has reached practical use.
