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Talking about the hiding power and transparency of organic pigments


  The hiding power and transparency of pigments are determined by optical properties. When the refractive index of the pigment is equal to its surrounding medium, it will be clear. When the refractive index of the pigment is greater than the refractive index of the medium, the hiding power will be generated. The greater the difference between the two, the stronger the hiding power.
  The hiding power and transparency of pigments are also related to the scattering and absorption rate of light by the pigment. The color with a large scattering rate or a high absorption capacity has a strong covering power.
  The hiding power or transparency of the pigment is related to the particle size of the pigment. Generally, the particle size of the inorganic pigment is large, and the hiding power is usually high; the dye is transparent because it is dissolved in the resin. It also depends on the application concentration of the pigment, the coloring material and the thickness. Transparency and hiding power are indicators that correspond to each other. For example, the higher the transparency of a pigment, the lower the hiding power, and vice versa. There is currently no unified standard for judging the transparency/hiding performance of pigments in plastic coloring. Generally, a coloring plastic sample should be made first, and then the sample should be placed on a black and white cardboard, and the black grid and white of the substrate should be observed. The grid part judges the degree of transparency through the degree of difference shown by the coloring sample. You can also use a colorimeter to test and compare the color difference between the whiteboard and the blackboard through the color sample. The larger the color difference, the higher the transparency.
  For the transparency/hiding power index, the following points should be paid attention to in the color matching of plastics:
  (1) The better the transparency of the colorant used for chemical fiber spinning products, the better the brightness and gloss of the spinning products.
  (2) Film products require good covering power of colorants. As we all know, in order to improve the hiding power of products, the method of adding titanium dioxide is usually used. However, after adding titanium dioxide to many colorants, not only the color light changes greatly, the tinting strength decreases, but also the application properties such as heat resistance and light resistance are also reduced.
  Pigments with high hiding power usually have high application value. If a pigment has high saturation, high hiding power and high holding power, it will be a product with extremely high commercial value.