carbon black Carbon black is the initial use of nano black pigment, and carbon black is cheap and widely used, but carbon black is also an inorganic pigment that is difficult to disperse in all pigments. We often hear that carbon black is not black enough. But what is the black of this carbon black? How to increase the black of carbon black?
1. The blackness of carbon black is closely related to the properties of carbon black. The primary particle size of carbon black is very small, ranging from several nanometers to hundreds of nanometers. The smaller the primary particle size of carbon black is, the larger the specific surface area of carbon black particles is, and the greater the light absorption performance is, the blacker it will be. Therefore, it can be simply said that, The smaller the primary particle size of carbon black, the higher the blackness.
2. The blackness of carbon black is closely related to the dispersion of carbon black. The use of carbon black needs to evenly disperse carbon black into the medium. The medium is various resins in the production process. Only when carbon black is evenly dispersed in the medium, can the performance of carbon black be reflected, including blackness and coloring.
3. How to disperse carbon black. His blackness dispersion generally includes the following steps: crushing, wetting, dispersing and maintaining. Crushing refers to the use of grinding equipment to crush and disperse carbon black aggregates. Wetting refers to the mixing and wrapping of medium and carbon black particles. Dispersion refers to the uniform dispersion of carbon black particles into the medium. Maintaining refers to the long-term stability of carbon black particles and uniform dispersion in the medium.
4. How to improve the blackness of carbon black. One is to change the particle size of carbon black, because the smaller the particle size, the blacker the carbon black, but to increase the oxygen-containing functional groups on the surface of carbon black and increase the adsorption of carbon black and medium; the third is to change the grinding equipment.
The coloring power is very important to carbon black. The stronger the coloring power is, the less the dosage is. The coloring power of carbon black is basically proportional to the particle size of carbon black, and has a certain relationship with the structure of carbon black. However, this relationship is not a simple relationship, because the coloring force of carbon black depends not only on the size of particle size, but also on its surface characteristics. Therefore, the relationship between blackness and coloring force is not proportional, so how to fully dye carbon black?
In the design of color paint formula, it is necessary to increase the amount of drying agent. If the carbon black with high specific surface area can not be well dispersed, the effect will be very poor. However, no matter how hard the medium pigment carbon black tries, no matter how much oil absorption of carbon black is, and how the viscosity of the system is, the effect of high pigment will not be made. Therefore, in most cases, the factor of color blackness should be considered first. So like pure black high-grade car paint, the first requirement for carbon black is blackness, according to this condition to choose different carbon black Products.
If the pigment is evenly dispersed in the base material, the particle size will be small, the specific surface area will be increased, and the covering capacity will be increased. However, if the particle size of pigment is equal to half of the wavelength of light, the light will pass through the particles without refraction. In fact, the covering power of most mixed pigments is larger than the calculated value. Therefore, the mixture of pigment and filler in proper proportion will not affect the covering power and reduce the cost.