Poor Coverage Of Pigments? These Factors Affect!

The factors that affect pigment cover are refractive index, ability to absorb light, crystal structure and dispersion.
(1) Refractive Index The pigment's masking force is strong, depending on the size of its refractive index, and the large coverage force of the refractive index is strong. In a coating film containing pigments, the refractive index of the pigment is the same as that of the substrate, and the pigment appears transparent within the film without covering it, which is called a transparent pigment. The greater the difference between the refractive index of the pigment and the refractive index of the substrate, the stronger the pigment's masking force. For example, the refractive index of titanium dioxide is about 2.5, the refractive index of polymer is about 1.3, so titanium dioxide to the polymer is a strong pigment.
(2) The ability to absorb light The masking power of the pigment also depends on the absorption capacity of the pigment to the light shot above it. Carbon black, for example, does not reflect light at all and absorbs all the light fired on it, making it a highly covering pigment.
3 Crystal structure The stronger the crystal structure of the pigment, the stronger the masking force. Pigments with weak or obviously amorphous structures have a lower masking force. Such as gold-redstone titanium white powder and sharp titanium white powder crystal shape is different, the masking force is also different, the former is higher than the latter.
(4) Dispersion Degree When other conditions are the same, the pigment's masking power depends on how dispersed they are. The higher the dispersion, the stronger the masking force. But there is a certain limit to this relationship, when the size of pigment particles become equal to half of the wavelength of light, that is, to reach the limit of the masking force, light will penetrate the particles without being refracted, such particles appear transparent, such as nano-titanium dioxide and so on.