Extinction powder Matte powder DongCao E-1011 Extinction powder for UV

Extinction powder, also known as matte powder, is mainly used in paint, ink to change the brightness of the powder. The powder's color is white. Optional products are 25#, OK520, OK607, Dongcao E-1011 (special for UV). Packing for 10KG/bag.
Extinction powder, also known as matte powder, is mainly used in paint, ink to change the brightness of the powder. The powder's color is white. Optional products are 25#, OK520, OK607, Dongcao E-1011 (special for UV). Packing for 10KG/bag.
1, Extinction principle
The gloss of the object surface is closely related to the roughness of the object surface. When light strikes the surface of an object, some of it will be absorbed, some will be reflected and scattered, and some will be refracted. The smaller the surface roughness is, the more light is reflected and the higher the glossiness is. On the contrary, if the surface of the object is uneven and the scattered light increases, the glossiness decreases, and the surface roughness (h) of the bright object can be sensed by human vision, the theoretical knowledge of micro-surface can be used to calculate the wavelength of human light according to the formula: h = λ/cosα; α is the incident angle. For example, when the angle of fire is 60 degrees, h = 1.1μm can be calculated. When the surface roughness h is greater than 1.1μm, it will be uneven and gloss will be reduced.
2, Film Formation Process of Coatings
After coating on the surface of the object, the film is solidified by volatilization of solvent (for solvent-based coatings). The formation process of coating film is very important to the roughness and gloss of coating surface. In the wet film stage, the volatilization rate of solvents is controlled by the diffusion of solvents on the film surface. When the volatilization rates of solvents are not different, it is possible to obtain a glossy surface. On the contrary, when the volatilization rates of solvents are different in the wet film stage, it will make polymer molecules tend to curl or even precipitate into particles or clusters of different sizes. The surface of the coating is uneven. In the dry film stage, the volatilization rate of solvents is mainly controlled by the diffusion of solvents in the whole coating, and also affects the roughness of the coating surface. In addition, in the process of film formation, with the volatilization of solvent, the film will become thinner and shrink, and some suspended heavy particles will rearrange on the surface of the film, resulting in uneven surface of the film.
3, Particle Size and Distribution of Pigments and Fines
The particle size and particle size distribution of pigments (fillers) in coatings are one of the important factors affecting the gloss of coatings. It has been found that a high gloss coating can be obtained when the diameter of the pigment particles is less than 0.3 um. The reason is that the pigment particles dispersed in the coating are formed into a film with a certain thickness, and after drying, only the upper layer of the pigment particles are protruded locally. The surface roughness of the coating caused by the pigment ions whose particle diameter is less than 0.3 micron will not exceed 0.1 micron. When the average particle diameter of pigments is between 3 and 5 microns, a better extinction coating can be obtained.
In addition to the above three factors can affect the coating surface gloss, pigment volume concentration (PVC), pigment dispersion and coating surface structure and surface reflection characteristics and other factors can also affect the coating surface gloss.Among them, with the increase of PVC of pigment, the glossiness of coating film surface first decreases, and the minimum value appears at the limit volume concentration of pigment (CPVC), and then with the increase of PVC, the glossiness also increases.When the type and amount of pigment is determined, the better the dispersion, the higher the gloss of the coating surface.