What factors are related to the covering rate of masterbatch pigments?

Technical Information, 09-28-2018

1. Light absorption characteristics of pigment itself

Generally, pigments with strong light absorbing ability have large hiding power, such as carbon black, which can absorb almost all incident light. It is a pigment with very good hiding power.
2. Refractive index difference with matrix resin
The greater the difference between the refractive index of the pigment crystal and that of the resin, the stronger the hiding power of the pigment to the resin.
3. Particle size of pigment particles
The particle size of pigment is inversely proportional to the hiding power, that is, the larger the particle size of pigment, the smaller the hiding power, and the greater the hiding power, but there is a certain limit. When the diameter of the pigment particle is smaller than the wavelength of the light wave, the light will no longer be reflected by the pigment particle. At this time, the covering power drops rapidly. Generally, when the diameter of the pigment particle is 0.5 μ m, the covering power is strong:
4. Crystal form of pigment
The symmetry of pigment molecular structure crystal form is inversely proportional to the hiding power; The covering power of pigment type with large surface area is stronger than that with small surface area, for example, the covering power of flake crystal type pigment is greater than that of needle type pigment; Pigments with high crystallinity have greater hiding power than those with low crystallinity.