Requirements for Pigment Carbon Black in different inks
(1) Carbon Black Pigment for Letterpress rotary ink (letterplate ink)
The ink is required to have high fluidity when the pigment carbon black content is high. Therefore, the carbon black is required to be easy to disperse, show a blue phase (less blue pigment can be used), less penetrate into the paper, and have low page wear. For this reason, pigment carbon black products with larger granularity (around 27nm) and higher DBP value (100-120ml/100g) without surface oxidation treatment are preferred.
(2) Carbon Black Pigment for Offset ink
Since the ink film is thinner than that of letterpress, the concentration of carbon black in the ink must be high and it must have good rheology. Therefore, the carbon black is required to be easy to disperse, have low page wear, show a blue phase and have low ink color fall-off. Its requirements are similar to those of letterpress rotation. The inks are basically the same, and the recommended varieties are also similar.
Practice shows that the wear of black ink on the layout mainly depends on the ash composition of pigment carbon black (affected by the quality of raw oil) and has little to do with the type of pigment carbon black. When users have outstanding requirements for the rheology and color shedding of the ink, it is recommended to use or combine carbon black varieties with lower structures. (Particle size 27-36nm, DBP60-70ml/100g)
(3) Pigment Carbon Black For Ink for books, periodicals and pictorials
Letterpress and offset offset printing inks are basically the same, that is, carbon black is required to have excellent dispersion ability, low oil absorption value, high blackness and excellent fluidity, so that the printed matter has high blackness and high gloss.
Due to different grades of printed matter, it is recommended to use it. The types of carbon black are also different. For high-end ink pigment carbon black, it is recommended to use long-flow furnace black with finer particle size (24-25nm) and lower oil absorption (55-70ml/100g) with or without oxidation treatment. Medium flow The particle size is the smallest among furnace black and ordinary pigment furnace black. The play introduces the use ratio of carbon black with larger particle size and low structure, which can be increased, resulting in good tinting strength and gloss, blue phase, and low cost.
(4) Carbon Black Powder for Gravure ink
Pigment Carbon black is required to have low viscosity, blue phase, easy wetting, easy dispersion and stable dispersion performance. Therefore, it is appropriate to use carbon black with larger particle size (36-75nm) and low oil absorption (40-70ml/100g). The ink requirements for flexographic plates are similar to those for gravure inks. Perhaps because the prints require higher blackness, it is recommended to use carbon black with finer particle size (25-27nm) and lower oil absorption (50-70ml/100g). Or long flowing carbon black.
