Various pigment carbon blacks can be used for plastic coloring.
The finest (13-19nm) high-pigment carbon black or medium-pigment carbon black is suitable for plastic products with extremely high blackness requirements. For plastics with obvious qualities such as ABS, the addition amount of carbon black is about 1%-2%, and 0.5%-1.0% of other plastics is enough.
For black plastic products with low blackness and gloss requirements, ordinary pigment carbon black with a medium particle size (20-25 nm) can be used.
When plastics are used for coloration, such as red dates, light browns, grass greens, sky blues, and various darker colors, it is necessary to add trace amounts of carbon black. Since the addition amount is often only a few ten thousandths, the tiny errors that occur when sizing and compounding the carbon black will cause significant color differences. Therefore, it is preferable to use a pigment with a large particle size (greater than 50 nm) and poor coloring power. Carbon black, so that the amount of carbon black can be slightly larger, the weighing error is relatively small, and there are advantages of better dispersion and lower prices.
For gray plastics, the fine particle carbon black is often brownish gray, whereas the coarse particle carbon black can produce a blue phase gray.