| 摘要 |
<p>Iron blue characterized by an ammonium content of +/-5.5 weight %, a potassium content of <0.1 weight %, a sodium content of <0.1 weight %, a color strength in a toluene intaglio printing ink up to 15% greater than the standard Vossen blue 705/80 (calculated in accordance with DIN 53 234) and the color spacings (determined in accordance with DIN 6174 relative to Vossen blue 705/80 as standard) of DELTA a*:6.5+/-0.5 DELTA b*:1.3+/-0.3 DELTA c*:-1.5+/-0.5 It is prepared by placing an aqueous solution of sodium hexacyanoferrate (II) in a reaction vessel at a pH of 7.0 and a concentration of 45+/-5 g/l, calculated as Fe(CN)6 together with ammonium sulfate having a concentration of 14+/-1 g/l at a temperature of 22 DEG -23 DEG C., adding an aqueous iron-II sulfate solution at a pH of 2.0, a concentration of 100+/-10 g/l, and a temperature of 22 DEG -23 DEG C., and precipitating the white dough until an excess of iron up to 1.4-1.7/1, calculated as Fe, is attained in the filtrate, then washing the white dough by decantation until the filtrate indicates a conductivity of 5000 to 5500 mu S and has an excess of iron of 0.1-0.2 g/l, calculated as Fe in the filtrate, then stirring in 58+/-6 g ammonium sulfate and boiling the white dough for a period of >/=2 hours, thereupon adding, at a temperature of 70 DEG +/-5 DEG C., first >/=90 g HCl as a 10-15% aqueous solution, then >/=51 g sodium chlorate as an aqueous solution having a concentration 270+/-30 g/l. The iron blue pigment can be used in printing inks.</p> |
